diff --git a/toolchain/check/testdata/alias/no_prelude/local.carbon b/toolchain/check/testdata/alias/min_prelude/local.carbon
similarity index 53%
rename from toolchain/check/testdata/alias/no_prelude/local.carbon
rename to toolchain/check/testdata/alias/min_prelude/local.carbon
index 215c109be6bf..00e148f938ac 100644
--- a/toolchain/check/testdata/alias/no_prelude/local.carbon
+++ b/toolchain/check/testdata/alias/min_prelude/local.carbon
@@ -2,11 +2,18 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/alias/no_prelude/local.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/alias/min_prelude/local.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/alias/no_prelude/local.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/alias/min_prelude/local.carbon
+
+// --- local.carbon
+
+library "[[@TEST_NAME]]";
 
 fn F() -> () {
   var a: () = ();
@@ -23,16 +30,24 @@ fn F() -> () {
 // CHECK:STDOUT:   %empty_tuple: %empty_tuple.type = tuple_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {
 // CHECK:STDOUT:     %return.patt: %empty_tuple.type = return_slot_pattern
 // CHECK:STDOUT:     %return.param_patt: %empty_tuple.type = out_param_pattern %return.patt, call_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %.loc11_12.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc11_12.2: type = converted %.loc11_12.1, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:     %.loc4_12.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc4_12.2: type = converted %.loc4_12.1, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
 // CHECK:STDOUT:     %return.param: ref %empty_tuple.type = out_param call_param0
 // CHECK:STDOUT:     %return: ref %empty_tuple.type = return_slot %return.param
 // CHECK:STDOUT:   }
@@ -42,23 +57,29 @@ fn F() -> () {
 // CHECK:STDOUT: !entry:
 // CHECK:STDOUT:   name_binding_decl {
 // CHECK:STDOUT:     %a.patt: %empty_tuple.type = binding_pattern a
-// CHECK:STDOUT:     %.loc12_3.1: %empty_tuple.type = var_pattern %a.patt
+// CHECK:STDOUT:     %.loc5_3.1: %empty_tuple.type = var_pattern %a.patt
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %a.var: ref %empty_tuple.type = var a
-// CHECK:STDOUT:   %.loc12_16.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc12_16.2: init %empty_tuple.type = tuple_init () to %a.var [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   %.loc12_3.2: init %empty_tuple.type = converted %.loc12_16.1, %.loc12_16.2 [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   assign %a.var, %.loc12_3.2
-// CHECK:STDOUT:   %.loc12_11.1: type = splice_block %.loc12_11.3 [concrete = constants.%empty_tuple.type] {
-// CHECK:STDOUT:     %.loc12_11.2: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc12_11.3: type = converted %.loc12_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:   %.loc5_16.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:   %.loc5_16.2: init %empty_tuple.type = tuple_init () to %a.var [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   %.loc5_3.2: init %empty_tuple.type = converted %.loc5_16.1, %.loc5_16.2 [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   assign %a.var, %.loc5_3.2
+// CHECK:STDOUT:   %.loc5_11.1: type = splice_block %.loc5_11.3 [concrete = constants.%empty_tuple.type] {
+// CHECK:STDOUT:     %.loc5_11.2: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc5_11.3: type = converted %.loc5_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %a: ref %empty_tuple.type = bind_name a, %a.var
 // CHECK:STDOUT:   %a.ref: ref %empty_tuple.type = name_ref a, %a
 // CHECK:STDOUT:   %b: ref %empty_tuple.type = bind_alias b, %a
 // CHECK:STDOUT:   %b.ref: ref %empty_tuple.type = name_ref b, %b
 // CHECK:STDOUT:   %tuple: %empty_tuple.type = tuple_value () [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   %.loc14: %empty_tuple.type = converted %b.ref, %tuple [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   return %.loc14
+// CHECK:STDOUT:   %.loc7: %empty_tuple.type = converted %b.ref, %tuple [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   return %.loc7
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
diff --git a/toolchain/check/testdata/alias/no_prelude/fail_not_constant.carbon b/toolchain/check/testdata/alias/no_prelude/fail_not_constant.carbon
index 7e194365f217..4e09914f37bf 100644
--- a/toolchain/check/testdata/alias/no_prelude/fail_not_constant.carbon
+++ b/toolchain/check/testdata/alias/no_prelude/fail_not_constant.carbon
@@ -8,67 +8,65 @@
 // TIP: To dump output, run:
 // TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/alias/no_prelude/fail_not_constant.carbon
 
-fn F() {
-  var a: () = ();
-  var b: ()* = &a;
-  // CHECK:STDERR: fail_not_constant.carbon:[[@LINE+4]]:13: error: alias initializer must be a name reference [AliasRequiresNameRef]
-  // CHECK:STDERR:   alias c = *b;
-  // CHECK:STDERR:             ^~
-  // CHECK:STDERR:
-  alias c = *b;
-}
+var a: () = ();
+var b: ()* = &a;
+
+// CHECK:STDERR: fail_not_constant.carbon:[[@LINE+4]]:11: error: alias initializer must be a name reference [AliasRequiresNameRef]
+// CHECK:STDERR: alias c = *b;
+// CHECK:STDERR:           ^~
+// CHECK:STDERR:
+alias c = *b;
 
 // CHECK:STDOUT: --- fail_not_constant.carbon
 // CHECK:STDOUT:
 // CHECK:STDOUT: constants {
-// CHECK:STDOUT:   %F.type: type = fn_type @F [concrete]
 // CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
-// CHECK:STDOUT:   %F: %F.type = struct_value () [concrete]
 // CHECK:STDOUT:   %empty_tuple: %empty_tuple.type = tuple_value () [concrete]
 // CHECK:STDOUT:   %ptr: type = ptr_type %empty_tuple.type [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
-// CHECK:STDOUT:     .F = %F.decl
+// CHECK:STDOUT:     .a = %a
+// CHECK:STDOUT:     .b = %b
+// CHECK:STDOUT:     .c = %c
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: fn @F() {
-// CHECK:STDOUT: !entry:
 // CHECK:STDOUT:   name_binding_decl {
 // CHECK:STDOUT:     %a.patt: %empty_tuple.type = binding_pattern a
-// CHECK:STDOUT:     %.loc12_3.1: %empty_tuple.type = var_pattern %a.patt
+// CHECK:STDOUT:     %.loc11_1: %empty_tuple.type = var_pattern %a.patt
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %a.var: ref %empty_tuple.type = var a
-// CHECK:STDOUT:   %.loc12_16.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc12_16.2: init %empty_tuple.type = tuple_init () to %a.var [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   %.loc12_3.2: init %empty_tuple.type = converted %.loc12_16.1, %.loc12_16.2 [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   assign %a.var, %.loc12_3.2
-// CHECK:STDOUT:   %.loc12_11.1: type = splice_block %.loc12_11.3 [concrete = constants.%empty_tuple.type] {
-// CHECK:STDOUT:     %.loc12_11.2: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc12_11.3: type = converted %.loc12_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:   %.loc11_9.1: type = splice_block %.loc11_9.3 [concrete = constants.%empty_tuple.type] {
+// CHECK:STDOUT:     %.loc11_9.2: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc11_9.3: type = converted %.loc11_9.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %a: ref %empty_tuple.type = bind_name a, %a.var
 // CHECK:STDOUT:   name_binding_decl {
 // CHECK:STDOUT:     %b.patt: %ptr = binding_pattern b
-// CHECK:STDOUT:     %.loc13_3: %ptr = var_pattern %b.patt
+// CHECK:STDOUT:     %.loc12_1: %ptr = var_pattern %b.patt
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %b.var: ref %ptr = var b
-// CHECK:STDOUT:   %a.ref: ref %empty_tuple.type = name_ref a, %a
-// CHECK:STDOUT:   %addr: %ptr = addr_of %a.ref
-// CHECK:STDOUT:   assign %b.var, %addr
-// CHECK:STDOUT:   %.loc13_12.1: type = splice_block %ptr [concrete = constants.%ptr] {
-// CHECK:STDOUT:     %.loc13_11: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc13_12.2: type = converted %.loc13_11, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
-// CHECK:STDOUT:     %ptr: type = ptr_type %.loc13_12.2 [concrete = constants.%ptr]
+// CHECK:STDOUT:   %.loc12_10.1: type = splice_block %ptr [concrete = constants.%ptr] {
+// CHECK:STDOUT:     %.loc12_9: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc12_10.2: type = converted %.loc12_9, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:     %ptr: type = ptr_type %.loc12_10.2 [concrete = constants.%ptr]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %b: ref %ptr = bind_name b, %b.var
 // CHECK:STDOUT:   %b.ref: ref %ptr = name_ref b, %b
-// CHECK:STDOUT:   %.loc18_14: %ptr = bind_value %b.ref
-// CHECK:STDOUT:   %.loc18_13: ref %empty_tuple.type = deref %.loc18_14
+// CHECK:STDOUT:   %.loc18_12: %ptr = bind_value %b.ref
+// CHECK:STDOUT:   %.loc18_11: ref %empty_tuple.type = deref %.loc18_12
 // CHECK:STDOUT:   %c: <error> = bind_alias c, <error> [concrete = <error>]
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: fn @__global_init() {
+// CHECK:STDOUT: !entry:
+// CHECK:STDOUT:   %.loc11_14.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:   %.loc11_14.2: init %empty_tuple.type = tuple_init () to file.%a.var [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   %.loc11_1: init %empty_tuple.type = converted %.loc11_14.1, %.loc11_14.2 [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   assign file.%a.var, %.loc11_1
+// CHECK:STDOUT:   %a.ref: ref %empty_tuple.type = name_ref a, file.%a
+// CHECK:STDOUT:   %addr: %ptr = addr_of %a.ref
+// CHECK:STDOUT:   assign file.%b.var, %addr
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
diff --git a/toolchain/check/testdata/as/no_prelude/tuple.carbon b/toolchain/check/testdata/as/min_prelude/tuple.carbon
similarity index 55%
rename from toolchain/check/testdata/as/no_prelude/tuple.carbon
rename to toolchain/check/testdata/as/min_prelude/tuple.carbon
index 3e40016fb506..b32fabffc2e2 100644
--- a/toolchain/check/testdata/as/no_prelude/tuple.carbon
+++ b/toolchain/check/testdata/as/min_prelude/tuple.carbon
@@ -2,11 +2,18 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/as/no_prelude/tuple.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/as/min_prelude/tuple.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/as/no_prelude/tuple.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/as/min_prelude/tuple.carbon
+
+// --- test.carbon
+
+library "[[@TEST_NAME]]";
 
 class X {
   // ...
@@ -24,7 +31,7 @@ fn Var() {
   var b: (X, X) = (Make(), Make()) as (X, X);
 }
 
-// CHECK:STDOUT: --- tuple.carbon
+// CHECK:STDOUT: --- test.carbon
 // CHECK:STDOUT:
 // CHECK:STDOUT: constants {
 // CHECK:STDOUT:   %X: type = class_type @X [concrete]
@@ -40,13 +47,21 @@ fn Var() {
 // CHECK:STDOUT:   %Var: %Var.type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .X = %X.decl
 // CHECK:STDOUT:     .Make = %Make.decl
 // CHECK:STDOUT:     .Let = %Let.decl
 // CHECK:STDOUT:     .Var = %Var.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %X.decl: type = class_decl @X [concrete = constants.%X] {} {}
 // CHECK:STDOUT:   %Make.decl: %Make.type = fn_decl @Make [concrete = constants.%Make] {
 // CHECK:STDOUT:     %return.patt: %X = return_slot_pattern
@@ -76,30 +91,30 @@ fn Var() {
 // CHECK:STDOUT:   name_binding_decl {
 // CHECK:STDOUT:     %a.patt: %tuple.type.b67 = binding_pattern a
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %Make.ref.loc19_20: %Make.type = name_ref Make, file.%Make.decl [concrete = constants.%Make]
-// CHECK:STDOUT:   %.loc19_25.1: ref %X = temporary_storage
-// CHECK:STDOUT:   %Make.call.loc19_25: init %X = call %Make.ref.loc19_20() to %.loc19_25.1
-// CHECK:STDOUT:   %Make.ref.loc19_28: %Make.type = name_ref Make, file.%Make.decl [concrete = constants.%Make]
-// CHECK:STDOUT:   %.loc19_33.1: ref %X = temporary_storage
-// CHECK:STDOUT:   %Make.call.loc19_33: init %X = call %Make.ref.loc19_28() to %.loc19_33.1
-// CHECK:STDOUT:   %.loc19_34.1: %tuple.type.b67 = tuple_literal (%Make.call.loc19_25, %Make.call.loc19_33)
-// CHECK:STDOUT:   %X.ref.loc19_40: type = name_ref X, file.%X.decl [concrete = constants.%X]
-// CHECK:STDOUT:   %X.ref.loc19_43: type = name_ref X, file.%X.decl [concrete = constants.%X]
-// CHECK:STDOUT:   %.loc19_44.1: %tuple.type.24b = tuple_literal (%X.ref.loc19_40, %X.ref.loc19_43)
-// CHECK:STDOUT:   %.loc19_44.2: type = converted %.loc19_44.1, constants.%tuple.type.b67 [concrete = constants.%tuple.type.b67]
-// CHECK:STDOUT:   %.loc19_15.1: type = splice_block %.loc19_15.3 [concrete = constants.%tuple.type.b67] {
-// CHECK:STDOUT:     %X.ref.loc19_11: type = name_ref X, file.%X.decl [concrete = constants.%X]
-// CHECK:STDOUT:     %X.ref.loc19_14: type = name_ref X, file.%X.decl [concrete = constants.%X]
-// CHECK:STDOUT:     %.loc19_15.2: %tuple.type.24b = tuple_literal (%X.ref.loc19_11, %X.ref.loc19_14)
-// CHECK:STDOUT:     %.loc19_15.3: type = converted %.loc19_15.2, constants.%tuple.type.b67 [concrete = constants.%tuple.type.b67]
+// CHECK:STDOUT:   %Make.ref.loc12_20: %Make.type = name_ref Make, file.%Make.decl [concrete = constants.%Make]
+// CHECK:STDOUT:   %.loc12_25.1: ref %X = temporary_storage
+// CHECK:STDOUT:   %Make.call.loc12_25: init %X = call %Make.ref.loc12_20() to %.loc12_25.1
+// CHECK:STDOUT:   %Make.ref.loc12_28: %Make.type = name_ref Make, file.%Make.decl [concrete = constants.%Make]
+// CHECK:STDOUT:   %.loc12_33.1: ref %X = temporary_storage
+// CHECK:STDOUT:   %Make.call.loc12_33: init %X = call %Make.ref.loc12_28() to %.loc12_33.1
+// CHECK:STDOUT:   %.loc12_34.1: %tuple.type.b67 = tuple_literal (%Make.call.loc12_25, %Make.call.loc12_33)
+// CHECK:STDOUT:   %X.ref.loc12_40: type = name_ref X, file.%X.decl [concrete = constants.%X]
+// CHECK:STDOUT:   %X.ref.loc12_43: type = name_ref X, file.%X.decl [concrete = constants.%X]
+// CHECK:STDOUT:   %.loc12_44.1: %tuple.type.24b = tuple_literal (%X.ref.loc12_40, %X.ref.loc12_43)
+// CHECK:STDOUT:   %.loc12_44.2: type = converted %.loc12_44.1, constants.%tuple.type.b67 [concrete = constants.%tuple.type.b67]
+// CHECK:STDOUT:   %.loc12_15.1: type = splice_block %.loc12_15.3 [concrete = constants.%tuple.type.b67] {
+// CHECK:STDOUT:     %X.ref.loc12_11: type = name_ref X, file.%X.decl [concrete = constants.%X]
+// CHECK:STDOUT:     %X.ref.loc12_14: type = name_ref X, file.%X.decl [concrete = constants.%X]
+// CHECK:STDOUT:     %.loc12_15.2: %tuple.type.24b = tuple_literal (%X.ref.loc12_11, %X.ref.loc12_14)
+// CHECK:STDOUT:     %.loc12_15.3: type = converted %.loc12_15.2, constants.%tuple.type.b67 [concrete = constants.%tuple.type.b67]
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %.loc19_25.2: ref %X = temporary %.loc19_25.1, %Make.call.loc19_25
-// CHECK:STDOUT:   %.loc19_25.3: %X = bind_value %.loc19_25.2
-// CHECK:STDOUT:   %.loc19_33.2: ref %X = temporary %.loc19_33.1, %Make.call.loc19_33
-// CHECK:STDOUT:   %.loc19_33.3: %X = bind_value %.loc19_33.2
-// CHECK:STDOUT:   %tuple: %tuple.type.b67 = tuple_value (%.loc19_25.3, %.loc19_33.3)
-// CHECK:STDOUT:   %.loc19_34.2: %tuple.type.b67 = converted %.loc19_34.1, %tuple
-// CHECK:STDOUT:   %a: %tuple.type.b67 = bind_name a, %.loc19_34.2
+// CHECK:STDOUT:   %.loc12_25.2: ref %X = temporary %.loc12_25.1, %Make.call.loc12_25
+// CHECK:STDOUT:   %.loc12_25.3: %X = bind_value %.loc12_25.2
+// CHECK:STDOUT:   %.loc12_33.2: ref %X = temporary %.loc12_33.1, %Make.call.loc12_33
+// CHECK:STDOUT:   %.loc12_33.3: %X = bind_value %.loc12_33.2
+// CHECK:STDOUT:   %tuple: %tuple.type.b67 = tuple_value (%.loc12_25.3, %.loc12_33.3)
+// CHECK:STDOUT:   %.loc12_34.2: %tuple.type.b67 = converted %.loc12_34.1, %tuple
+// CHECK:STDOUT:   %a: %tuple.type.b67 = bind_name a, %.loc12_34.2
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -107,30 +122,36 @@ fn Var() {
 // CHECK:STDOUT: !entry:
 // CHECK:STDOUT:   name_binding_decl {
 // CHECK:STDOUT:     %b.patt: %tuple.type.b67 = binding_pattern b
-// CHECK:STDOUT:     %.loc24_3.1: %tuple.type.b67 = var_pattern %b.patt
+// CHECK:STDOUT:     %.loc17_3.1: %tuple.type.b67 = var_pattern %b.patt
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %b.var: ref %tuple.type.b67 = var b
-// CHECK:STDOUT:   %Make.ref.loc24_20: %Make.type = name_ref Make, file.%Make.decl [concrete = constants.%Make]
+// CHECK:STDOUT:   %Make.ref.loc17_20: %Make.type = name_ref Make, file.%Make.decl [concrete = constants.%Make]
 // CHECK:STDOUT:   %tuple.elem0: ref %X = tuple_access %b.var, element0
-// CHECK:STDOUT:   %Make.call.loc24_25: init %X = call %Make.ref.loc24_20() to %tuple.elem0
-// CHECK:STDOUT:   %Make.ref.loc24_28: %Make.type = name_ref Make, file.%Make.decl [concrete = constants.%Make]
+// CHECK:STDOUT:   %Make.call.loc17_25: init %X = call %Make.ref.loc17_20() to %tuple.elem0
+// CHECK:STDOUT:   %Make.ref.loc17_28: %Make.type = name_ref Make, file.%Make.decl [concrete = constants.%Make]
 // CHECK:STDOUT:   %tuple.elem1: ref %X = tuple_access %b.var, element1
-// CHECK:STDOUT:   %Make.call.loc24_33: init %X = call %Make.ref.loc24_28() to %tuple.elem1
-// CHECK:STDOUT:   %.loc24_34.1: %tuple.type.b67 = tuple_literal (%Make.call.loc24_25, %Make.call.loc24_33)
-// CHECK:STDOUT:   %X.ref.loc24_40: type = name_ref X, file.%X.decl [concrete = constants.%X]
-// CHECK:STDOUT:   %X.ref.loc24_43: type = name_ref X, file.%X.decl [concrete = constants.%X]
-// CHECK:STDOUT:   %.loc24_44.1: %tuple.type.24b = tuple_literal (%X.ref.loc24_40, %X.ref.loc24_43)
-// CHECK:STDOUT:   %.loc24_44.2: type = converted %.loc24_44.1, constants.%tuple.type.b67 [concrete = constants.%tuple.type.b67]
-// CHECK:STDOUT:   %.loc24_34.2: init %tuple.type.b67 = tuple_init (%Make.call.loc24_25, %Make.call.loc24_33) to %b.var
-// CHECK:STDOUT:   %.loc24_3.2: init %tuple.type.b67 = converted %.loc24_34.1, %.loc24_34.2
-// CHECK:STDOUT:   assign %b.var, %.loc24_3.2
-// CHECK:STDOUT:   %.loc24_15.1: type = splice_block %.loc24_15.3 [concrete = constants.%tuple.type.b67] {
-// CHECK:STDOUT:     %X.ref.loc24_11: type = name_ref X, file.%X.decl [concrete = constants.%X]
-// CHECK:STDOUT:     %X.ref.loc24_14: type = name_ref X, file.%X.decl [concrete = constants.%X]
-// CHECK:STDOUT:     %.loc24_15.2: %tuple.type.24b = tuple_literal (%X.ref.loc24_11, %X.ref.loc24_14)
-// CHECK:STDOUT:     %.loc24_15.3: type = converted %.loc24_15.2, constants.%tuple.type.b67 [concrete = constants.%tuple.type.b67]
+// CHECK:STDOUT:   %Make.call.loc17_33: init %X = call %Make.ref.loc17_28() to %tuple.elem1
+// CHECK:STDOUT:   %.loc17_34.1: %tuple.type.b67 = tuple_literal (%Make.call.loc17_25, %Make.call.loc17_33)
+// CHECK:STDOUT:   %X.ref.loc17_40: type = name_ref X, file.%X.decl [concrete = constants.%X]
+// CHECK:STDOUT:   %X.ref.loc17_43: type = name_ref X, file.%X.decl [concrete = constants.%X]
+// CHECK:STDOUT:   %.loc17_44.1: %tuple.type.24b = tuple_literal (%X.ref.loc17_40, %X.ref.loc17_43)
+// CHECK:STDOUT:   %.loc17_44.2: type = converted %.loc17_44.1, constants.%tuple.type.b67 [concrete = constants.%tuple.type.b67]
+// CHECK:STDOUT:   %.loc17_34.2: init %tuple.type.b67 = tuple_init (%Make.call.loc17_25, %Make.call.loc17_33) to %b.var
+// CHECK:STDOUT:   %.loc17_3.2: init %tuple.type.b67 = converted %.loc17_34.1, %.loc17_34.2
+// CHECK:STDOUT:   assign %b.var, %.loc17_3.2
+// CHECK:STDOUT:   %.loc17_15.1: type = splice_block %.loc17_15.3 [concrete = constants.%tuple.type.b67] {
+// CHECK:STDOUT:     %X.ref.loc17_11: type = name_ref X, file.%X.decl [concrete = constants.%X]
+// CHECK:STDOUT:     %X.ref.loc17_14: type = name_ref X, file.%X.decl [concrete = constants.%X]
+// CHECK:STDOUT:     %.loc17_15.2: %tuple.type.24b = tuple_literal (%X.ref.loc17_11, %X.ref.loc17_14)
+// CHECK:STDOUT:     %.loc17_15.3: type = converted %.loc17_15.2, constants.%tuple.type.b67 [concrete = constants.%tuple.type.b67]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %b: ref %tuple.type.b67 = bind_name b, %b.var
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/builtins/no_prelude/no_op.carbon b/toolchain/check/testdata/builtins/no_prelude/no_op.carbon
index 1408bce57f24..4fcb6b2b048e 100644
--- a/toolchain/check/testdata/builtins/no_prelude/no_op.carbon
+++ b/toolchain/check/testdata/builtins/no_prelude/no_op.carbon
@@ -44,9 +44,7 @@ library "[[@TEST_NAME]]";
 
 fn NoOp() = "no_op";
 
-fn F() {
-  var x: () = NoOp();
-}
+var x: () = NoOp();
 
 // --- fail_signature.carbon
 
@@ -178,37 +176,34 @@ fn NoOp() -> {} = "no_op";
 // CHECK:STDOUT:   %NoOp.type: type = fn_type @NoOp [concrete]
 // CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
 // CHECK:STDOUT:   %NoOp: %NoOp.type = struct_value () [concrete]
-// CHECK:STDOUT:   %F.type: type = fn_type @F [concrete]
-// CHECK:STDOUT:   %F: %F.type = struct_value () [concrete]
 // CHECK:STDOUT:   %empty_tuple: %empty_tuple.type = tuple_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
 // CHECK:STDOUT:     .NoOp = %NoOp.decl
-// CHECK:STDOUT:     .F = %F.decl
+// CHECK:STDOUT:     .x = %x
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %NoOp.decl: %NoOp.type = fn_decl @NoOp [concrete = constants.%NoOp] {} {}
-// CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
+// CHECK:STDOUT:   name_binding_decl {
+// CHECK:STDOUT:     %x.patt: %empty_tuple.type = binding_pattern x
+// CHECK:STDOUT:     %.loc6_1: %empty_tuple.type = var_pattern %x.patt
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %x.var: ref %empty_tuple.type = var x
+// CHECK:STDOUT:   %.loc6_9.1: type = splice_block %.loc6_9.3 [concrete = constants.%empty_tuple.type] {
+// CHECK:STDOUT:     %.loc6_9.2: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc6_9.3: type = converted %.loc6_9.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %x: ref %empty_tuple.type = bind_name x, %x.var
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @NoOp() = "no_op";
 // CHECK:STDOUT:
-// CHECK:STDOUT: fn @F() {
+// CHECK:STDOUT: fn @__global_init() {
 // CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   name_binding_decl {
-// CHECK:STDOUT:     %x.patt: %empty_tuple.type = binding_pattern x
-// CHECK:STDOUT:     %.loc7_3: %empty_tuple.type = var_pattern %x.patt
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %x.var: ref %empty_tuple.type = var x
 // CHECK:STDOUT:   %NoOp.ref: %NoOp.type = name_ref NoOp, file.%NoOp.decl [concrete = constants.%NoOp]
 // CHECK:STDOUT:   %no_op: init %empty_tuple.type = call %NoOp.ref() [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   assign %x.var, %no_op
-// CHECK:STDOUT:   %.loc7_11.1: type = splice_block %.loc7_11.3 [concrete = constants.%empty_tuple.type] {
-// CHECK:STDOUT:     %.loc7_11.2: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc7_11.3: type = converted %.loc7_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %x: ref %empty_tuple.type = bind_name x, %x.var
+// CHECK:STDOUT:   assign file.%x.var, %no_op
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
diff --git a/toolchain/check/testdata/class/no_prelude/destroy_calls.carbon b/toolchain/check/testdata/class/min_prelude/destroy_calls.carbon
similarity index 95%
rename from toolchain/check/testdata/class/no_prelude/destroy_calls.carbon
rename to toolchain/check/testdata/class/min_prelude/destroy_calls.carbon
index a4f2a35faf64..05af490148da 100644
--- a/toolchain/check/testdata/class/no_prelude/destroy_calls.carbon
+++ b/toolchain/check/testdata/class/min_prelude/destroy_calls.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/class/no_prelude/destroy_calls.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/class/min_prelude/destroy_calls.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/class/no_prelude/destroy_calls.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/class/min_prelude/destroy_calls.carbon
 
 // --- types.carbon
 
@@ -126,12 +129,20 @@ fn G() { F({}); }
 // CHECK:STDOUT:   %destroy.8d0: %destroy.type.02f = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .NoAddr = %NoAddr.decl
 // CHECK:STDOUT:     .ExplicitReturn = %ExplicitReturn.decl
 // CHECK:STDOUT:     .WithAddr = %WithAddr.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %NoAddr.decl: type = class_decl @NoAddr [concrete = constants.%NoAddr] {} {}
 // CHECK:STDOUT:   %ExplicitReturn.decl: type = class_decl @ExplicitReturn [concrete = constants.%ExplicitReturn] {} {}
 // CHECK:STDOUT:   %WithAddr.decl: type = class_decl @WithAddr [concrete = constants.%WithAddr] {} {}
@@ -267,16 +278,19 @@ fn G() { F({}); }
 // CHECK:STDOUT:   %Main.NoAddr: type = import_ref Main//types, NoAddr, loaded [concrete = constants.%NoAddr]
 // CHECK:STDOUT:   %Main.ExplicitReturn: type = import_ref Main//types, ExplicitReturn, loaded [concrete = constants.%ExplicitReturn]
 // CHECK:STDOUT:   %Main.WithAddr: type = import_ref Main//types, WithAddr, loaded [concrete = constants.%WithAddr]
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Main.import_ref.8f24d3.1: <witness> = import_ref Main//types, loc7_1, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %Main.import_ref.f42 = import_ref Main//types, inst16 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.f42 = import_ref Main//types, inst18 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.b5b = import_ref Main//types, loc5_22, unloaded
 // CHECK:STDOUT:   %Main.import_ref.7fe: %destroy.type.bc5 = import_ref Main//types, loc6_27, loaded [concrete = constants.%destroy.60f]
 // CHECK:STDOUT:   %Main.import_ref.8f24d3.2: <witness> = import_ref Main//types, loc12_1, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %Main.import_ref.ee7 = import_ref Main//types, inst39 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.ee7 = import_ref Main//types, inst41 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.b14 = import_ref Main//types, loc10_30, unloaded
 // CHECK:STDOUT:   %Main.import_ref.83a: %destroy.type.dfa = import_ref Main//types, loc11_33, loaded [concrete = constants.%destroy.539]
 // CHECK:STDOUT:   %Main.import_ref.8f24d3.3: <witness> = import_ref Main//types, loc17_1, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %Main.import_ref.95d = import_ref Main//types, inst65 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.95d = import_ref Main//types, inst67 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.1cb = import_ref Main//types, loc15_24, unloaded
 // CHECK:STDOUT:   %Main.import_ref.54e: %destroy.type.02f = import_ref Main//types, loc16_33, loaded [concrete = constants.%destroy.8d0]
 // CHECK:STDOUT: }
@@ -286,8 +300,10 @@ fn G() { F({}); }
 // CHECK:STDOUT:     .NoAddr = imports.%Main.NoAddr
 // CHECK:STDOUT:     .ExplicitReturn = imports.%Main.ExplicitReturn
 // CHECK:STDOUT:     .WithAddr = imports.%Main.WithAddr
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %default.import = import <none>
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
 // CHECK:STDOUT: }
@@ -388,16 +404,19 @@ fn G() { F({}); }
 // CHECK:STDOUT:   %Main.NoAddr: type = import_ref Main//types, NoAddr, loaded [concrete = constants.%NoAddr]
 // CHECK:STDOUT:   %Main.ExplicitReturn: type = import_ref Main//types, ExplicitReturn, loaded [concrete = constants.%ExplicitReturn]
 // CHECK:STDOUT:   %Main.WithAddr: type = import_ref Main//types, WithAddr, loaded [concrete = constants.%WithAddr]
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Main.import_ref.8f24d3.1: <witness> = import_ref Main//types, loc7_1, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %Main.import_ref.f42 = import_ref Main//types, inst16 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.f42 = import_ref Main//types, inst18 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.b5b = import_ref Main//types, loc5_22, unloaded
 // CHECK:STDOUT:   %Main.import_ref.7fe: %destroy.type.bc5 = import_ref Main//types, loc6_27, loaded [concrete = constants.%destroy.60f]
 // CHECK:STDOUT:   %Main.import_ref.8f24d3.2: <witness> = import_ref Main//types, loc12_1, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %Main.import_ref.ee7 = import_ref Main//types, inst39 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.ee7 = import_ref Main//types, inst41 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.b14 = import_ref Main//types, loc10_30, unloaded
 // CHECK:STDOUT:   %Main.import_ref.83a: %destroy.type.dfa = import_ref Main//types, loc11_33, loaded [concrete = constants.%destroy.539]
 // CHECK:STDOUT:   %Main.import_ref.8f24d3.3: <witness> = import_ref Main//types, loc17_1, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %Main.import_ref.95d = import_ref Main//types, inst65 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.95d = import_ref Main//types, inst67 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.1cb = import_ref Main//types, loc15_24, unloaded
 // CHECK:STDOUT:   %Main.import_ref.54e: %destroy.type.02f = import_ref Main//types, loc16_33, loaded [concrete = constants.%destroy.8d0]
 // CHECK:STDOUT: }
@@ -407,8 +426,10 @@ fn G() { F({}); }
 // CHECK:STDOUT:     .NoAddr = imports.%Main.NoAddr
 // CHECK:STDOUT:     .ExplicitReturn = imports.%Main.ExplicitReturn
 // CHECK:STDOUT:     .WithAddr = imports.%Main.WithAddr
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %default.import = import <none>
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
 // CHECK:STDOUT: }
@@ -532,16 +553,19 @@ fn G() { F({}); }
 // CHECK:STDOUT:   %Main.NoAddr: type = import_ref Main//types, NoAddr, loaded [concrete = constants.%NoAddr]
 // CHECK:STDOUT:   %Main.ExplicitReturn: type = import_ref Main//types, ExplicitReturn, loaded [concrete = constants.%ExplicitReturn]
 // CHECK:STDOUT:   %Main.WithAddr: type = import_ref Main//types, WithAddr, loaded [concrete = constants.%WithAddr]
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Main.import_ref.8f24d3.1: <witness> = import_ref Main//types, loc7_1, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %Main.import_ref.f42 = import_ref Main//types, inst16 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.f42 = import_ref Main//types, inst18 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.784: %Make.type.bc9 = import_ref Main//types, loc5_22, loaded [concrete = constants.%Make.1be]
 // CHECK:STDOUT:   %Main.import_ref.7fe: %destroy.type.bc5 = import_ref Main//types, loc6_27, loaded [concrete = constants.%destroy.60f]
 // CHECK:STDOUT:   %Main.import_ref.8f24d3.2: <witness> = import_ref Main//types, loc12_1, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %Main.import_ref.ee7 = import_ref Main//types, inst39 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.ee7 = import_ref Main//types, inst41 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.8e0: %Make.type.378 = import_ref Main//types, loc10_30, loaded [concrete = constants.%Make.960]
 // CHECK:STDOUT:   %Main.import_ref.83a: %destroy.type.dfa = import_ref Main//types, loc11_33, loaded [concrete = constants.%destroy.539]
 // CHECK:STDOUT:   %Main.import_ref.8f24d3.3: <witness> = import_ref Main//types, loc17_1, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %Main.import_ref.95d = import_ref Main//types, inst65 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.95d = import_ref Main//types, inst67 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.974: %Make.type.e14 = import_ref Main//types, loc15_24, loaded [concrete = constants.%Make.b0a]
 // CHECK:STDOUT:   %Main.import_ref.54e: %destroy.type.02f = import_ref Main//types, loc16_33, loaded [concrete = constants.%destroy.8d0]
 // CHECK:STDOUT: }
@@ -551,8 +575,10 @@ fn G() { F({}); }
 // CHECK:STDOUT:     .NoAddr = imports.%Main.NoAddr
 // CHECK:STDOUT:     .ExplicitReturn = imports.%Main.ExplicitReturn
 // CHECK:STDOUT:     .WithAddr = imports.%Main.WithAddr
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %default.import = import <none>
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
 // CHECK:STDOUT: }
@@ -644,12 +670,20 @@ fn G() { F({}); }
 // CHECK:STDOUT:   %F: %F.type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .NoSelf = %NoSelf.decl
 // CHECK:STDOUT:     .Args = %Args.decl
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %NoSelf.decl: type = class_decl @NoSelf [concrete = constants.%NoSelf] {} {}
 // CHECK:STDOUT:   %Args.decl: type = class_decl @Args [concrete = constants.%Args] {} {}
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
@@ -747,12 +781,20 @@ fn G() { F({}); }
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .C = %C.decl
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:     .G = %G.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %C.decl: %C.type = class_decl @C [concrete = constants.%C.generic] {
 // CHECK:STDOUT:     %T.patt.loc4_18.1: type = symbolic_binding_pattern T, 0, template [template = %T.patt.loc4_18.2 (constants.%T.patt)]
 // CHECK:STDOUT:   } {
@@ -855,3 +897,9 @@ fn G() { F({}); }
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/class/no_prelude/destroy_decl.carbon b/toolchain/check/testdata/class/min_prelude/destroy_decl.carbon
similarity index 95%
rename from toolchain/check/testdata/class/no_prelude/destroy_decl.carbon
rename to toolchain/check/testdata/class/min_prelude/destroy_decl.carbon
index 195c7e685fbf..7924b9cf37f0 100644
--- a/toolchain/check/testdata/class/no_prelude/destroy_decl.carbon
+++ b/toolchain/check/testdata/class/min_prelude/destroy_decl.carbon
@@ -2,13 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
-// EXTRA-ARGS: --no-dump-sem-ir
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core --no-dump-sem-ir
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/class/no_prelude/destroy_decl.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/class/min_prelude/destroy_decl.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/class/no_prelude/destroy_decl.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/class/min_prelude/destroy_decl.carbon
 
 // --- self.carbon
 
diff --git a/toolchain/check/testdata/class/no_prelude/fail_abstract.carbon b/toolchain/check/testdata/class/min_prelude/fail_abstract.carbon
similarity index 91%
rename from toolchain/check/testdata/class/no_prelude/fail_abstract.carbon
rename to toolchain/check/testdata/class/min_prelude/fail_abstract.carbon
index 86f59253b795..65b2328bf797 100644
--- a/toolchain/check/testdata/class/no_prelude/fail_abstract.carbon
+++ b/toolchain/check/testdata/class/min_prelude/fail_abstract.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/class/no_prelude/fail_abstract.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/class/min_prelude/fail_abstract.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/class/no_prelude/fail_abstract.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/class/min_prelude/fail_abstract.carbon
 
 // --- fail_abstract_field.carbon
 
@@ -198,11 +201,19 @@ fn CallReturnAbstract() {
 // CHECK:STDOUT:   %Contains: type = class_type @Contains [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Abstract = %Abstract.decl
 // CHECK:STDOUT:     .Contains = %Contains.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Abstract.decl: type = class_decl @Abstract [concrete = constants.%Abstract] {} {}
 // CHECK:STDOUT:   %Contains.decl: type = class_decl @Contains [concrete = constants.%Contains] {} {}
 // CHECK:STDOUT: }
@@ -239,11 +250,19 @@ fn CallReturnAbstract() {
 // CHECK:STDOUT:   %Var: %Var.type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Abstract = %Abstract.decl
 // CHECK:STDOUT:     .Var = %Var.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Abstract.decl: type = class_decl @Abstract [concrete = constants.%Abstract] {} {}
 // CHECK:STDOUT:   %Var.decl: %Var.type = fn_decl @Var [concrete = constants.%Var] {} {}
 // CHECK:STDOUT: }
@@ -279,11 +298,19 @@ fn CallReturnAbstract() {
 // CHECK:STDOUT:   %F: %F.type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Abstract = %Abstract.decl
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Abstract.decl: type = class_decl @Abstract [concrete = constants.%Abstract] {} {}
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {
 // CHECK:STDOUT:     %a.patt: %Abstract = binding_pattern a
@@ -324,11 +351,19 @@ fn CallReturnAbstract() {
 // CHECK:STDOUT:   %Adapter: type = class_type @Adapter [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Abstract = %Abstract.decl
 // CHECK:STDOUT:     .Adapter = %Adapter.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Abstract.decl: type = class_decl @Abstract [concrete = constants.%Abstract] {} {}
 // CHECK:STDOUT:   %Adapter.decl: type = class_decl @Adapter [concrete = constants.%Adapter] {} {}
 // CHECK:STDOUT: }
@@ -366,12 +401,20 @@ fn CallReturnAbstract() {
 // CHECK:STDOUT:   %Call: %Call.type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Abstract = %Abstract.decl
 // CHECK:STDOUT:     .Param = %Param.decl
 // CHECK:STDOUT:     .Call = %Call.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Abstract.decl: type = class_decl @Abstract [concrete = constants.%Abstract] {} {}
 // CHECK:STDOUT:   %Param.decl: %Param.type = fn_decl @Param [concrete = constants.%Param] {
 // CHECK:STDOUT:     %a.patt: %Abstract = binding_pattern a
@@ -426,12 +469,20 @@ fn CallReturnAbstract() {
 // CHECK:STDOUT:   %struct_type.base.d.e0f: type = struct_type {.base: %empty_struct_type, .d: %empty_struct_type} [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Abstract = %Abstract.decl
 // CHECK:STDOUT:     .Derived = %Derived.decl
 // CHECK:STDOUT:     .Make = %Make.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Abstract.decl: type = class_decl @Abstract [concrete = constants.%Abstract] {} {}
 // CHECK:STDOUT:   %Derived.decl: type = class_decl @Derived [concrete = constants.%Derived] {} {}
 // CHECK:STDOUT:   %Make.decl: %Make.type = fn_decl @Make [concrete = constants.%Make] {
@@ -494,12 +545,20 @@ fn CallReturnAbstract() {
 // CHECK:STDOUT:   %Return: %Return.type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Abstract = %Abstract.decl
 // CHECK:STDOUT:     .Derived = %Derived.decl
 // CHECK:STDOUT:     .Return = %Return.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Abstract.decl: type = class_decl @Abstract [concrete = constants.%Abstract] {} {}
 // CHECK:STDOUT:   %Derived.decl: type = class_decl @Derived [concrete = constants.%Derived] {} {}
 // CHECK:STDOUT:   %Return.decl: %Return.type = fn_decl @Return [concrete = constants.%Return] {
@@ -567,12 +626,20 @@ fn CallReturnAbstract() {
 // CHECK:STDOUT:   %Access: %Access.type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Abstract = %Abstract.decl
 // CHECK:STDOUT:     .Derived = %Derived.decl
 // CHECK:STDOUT:     .Access = %Access.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Abstract.decl: type = class_decl @Abstract [concrete = constants.%Abstract] {} {}
 // CHECK:STDOUT:   %Derived.decl: type = class_decl @Derived [concrete = constants.%Derived] {} {}
 // CHECK:STDOUT:   %Access.decl: %Access.type = fn_decl @Access [concrete = constants.%Access] {
@@ -641,11 +708,19 @@ fn CallReturnAbstract() {
 // CHECK:STDOUT:   %F: %F.type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Abstract = %Abstract.decl
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Abstract.decl: type = class_decl @Abstract [concrete = constants.%Abstract] {} {}
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
 // CHECK:STDOUT: }
@@ -682,12 +757,20 @@ fn CallReturnAbstract() {
 // CHECK:STDOUT:   %CallReturnAbstract: %CallReturnAbstract.type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Abstract = %Abstract.decl
 // CHECK:STDOUT:     .ReturnAbstract = %ReturnAbstract.decl
 // CHECK:STDOUT:     .CallReturnAbstract = %CallReturnAbstract.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Abstract.decl: type = class_decl @Abstract [concrete = constants.%Abstract] {} {}
 // CHECK:STDOUT:   %ReturnAbstract.decl: %ReturnAbstract.type = fn_decl @ReturnAbstract [concrete = constants.%ReturnAbstract] {
 // CHECK:STDOUT:     %return.patt: %Abstract = return_slot_pattern
@@ -718,3 +801,9 @@ fn CallReturnAbstract() {
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/class/no_prelude/fail_abstract_in_tuple.carbon b/toolchain/check/testdata/class/min_prelude/fail_abstract_in_tuple.carbon
similarity index 89%
rename from toolchain/check/testdata/class/no_prelude/fail_abstract_in_tuple.carbon
rename to toolchain/check/testdata/class/min_prelude/fail_abstract_in_tuple.carbon
index 71568e893400..c4e13189386f 100644
--- a/toolchain/check/testdata/class/no_prelude/fail_abstract_in_tuple.carbon
+++ b/toolchain/check/testdata/class/min_prelude/fail_abstract_in_tuple.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/class/no_prelude/fail_abstract_in_tuple.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/class/min_prelude/fail_abstract_in_tuple.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/class/no_prelude/fail_abstract_in_tuple.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/class/min_prelude/fail_abstract_in_tuple.carbon
 
 // --- fail_abstract_field.carbon
 library "[[@TEST_NAME]]";
@@ -132,11 +135,19 @@ fn Var5() {
 // CHECK:STDOUT:   %tuple.type.f19: type = tuple_type (%Abstract1) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Abstract1 = %Abstract1.decl
 // CHECK:STDOUT:     .Contains = %Contains.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Abstract1.decl: type = class_decl @Abstract1 [concrete = constants.%Abstract1] {} {}
 // CHECK:STDOUT:   %Contains.decl: type = class_decl @Contains [concrete = constants.%Contains] {} {}
 // CHECK:STDOUT: }
@@ -177,11 +188,19 @@ fn Var5() {
 // CHECK:STDOUT:   %tuple.type.ac6: type = tuple_type (%Abstract2) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Abstract2 = %Abstract2.decl
 // CHECK:STDOUT:     .Var = %Var.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Abstract2.decl: type = class_decl @Abstract2 [concrete = constants.%Abstract2] {} {}
 // CHECK:STDOUT:   %Var.decl: %Var.type = fn_decl @Var [concrete = constants.%Var] {} {}
 // CHECK:STDOUT: }
@@ -223,11 +242,19 @@ fn Var5() {
 // CHECK:STDOUT:   %tuple.type.fa1: type = tuple_type (%Abstract3) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Abstract3 = %Abstract3.decl
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Abstract3.decl: type = class_decl @Abstract3 [concrete = constants.%Abstract3] {} {}
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {
 // CHECK:STDOUT:     %a.patt: %Abstract3 = binding_pattern a
@@ -277,12 +304,20 @@ fn Var5() {
 // CHECK:STDOUT:   %tuple.type.e3e: type = tuple_type (%Abstract4, %Abstract5) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Abstract4 = %Abstract4.decl
 // CHECK:STDOUT:     .Abstract5 = %Abstract5.decl
 // CHECK:STDOUT:     .Var2 = %Var2.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Abstract4.decl: type = class_decl @Abstract4 [concrete = constants.%Abstract4] {} {}
 // CHECK:STDOUT:   %Abstract5.decl: type = class_decl @Abstract5 [concrete = constants.%Abstract5] {} {}
 // CHECK:STDOUT:   %Var2.decl: %Var2.type = fn_decl @Var2 [concrete = constants.%Var2] {} {}
@@ -335,11 +370,19 @@ fn Var5() {
 // CHECK:STDOUT:   %tuple.type.d93: type = tuple_type (%Abstract6, %empty_struct_type) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Abstract6 = %Abstract6.decl
 // CHECK:STDOUT:     .Var3 = %Var3.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Abstract6.decl: type = class_decl @Abstract6 [concrete = constants.%Abstract6] {} {}
 // CHECK:STDOUT:   %Var3.decl: %Var3.type = fn_decl @Var3 [concrete = constants.%Var3] {} {}
 // CHECK:STDOUT: }
@@ -383,11 +426,19 @@ fn Var5() {
 // CHECK:STDOUT:   %tuple.type.919: type = tuple_type (%empty_struct_type, %Abstract7) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Abstract7 = %Abstract7.decl
 // CHECK:STDOUT:     .Var4 = %Var4.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Abstract7.decl: type = class_decl @Abstract7 [concrete = constants.%Abstract7] {} {}
 // CHECK:STDOUT:   %Var4.decl: %Var4.type = fn_decl @Var4 [concrete = constants.%Var4] {} {}
 // CHECK:STDOUT: }
@@ -427,10 +478,18 @@ fn Var5() {
 // CHECK:STDOUT:   %complete_type: <witness> = complete_type_witness %empty_struct_type [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Abstract = %Abstract.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Abstract.decl: type = class_decl @Abstract [concrete = constants.%Abstract] {} {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -457,15 +516,20 @@ fn Var5() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
 // CHECK:STDOUT:   %Main.Abstract: type = import_ref Main//lib, Abstract, loaded [concrete = constants.%Abstract]
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Main.import_ref.8f2: <witness> = import_ref Main//lib, loc3_26, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %Main.import_ref.ee1 = import_ref Main//lib, inst16 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.ee1 = import_ref Main//lib, inst18 [no loc], unloaded
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
 // CHECK:STDOUT:     .Abstract = imports.%Main.Abstract
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Var5 = %Var5.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %default.import = import <none>
 // CHECK:STDOUT:   %Var5.decl: %Var5.type = fn_decl @Var5 [concrete = constants.%Var5] {} {}
 // CHECK:STDOUT: }
@@ -493,3 +557,9 @@ fn Var5() {
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/class/no_prelude/fail_abstract_in_struct.carbon b/toolchain/check/testdata/class/no_prelude/fail_abstract_in_struct.carbon
index 0c62048edbcd..002d5ebba34c 100644
--- a/toolchain/check/testdata/class/no_prelude/fail_abstract_in_struct.carbon
+++ b/toolchain/check/testdata/class/no_prelude/fail_abstract_in_struct.carbon
@@ -29,16 +29,14 @@ library "[[@TEST_NAME]]";
 
 abstract class Abstract2 {}
 
-fn Var() {
-  // CHECK:STDERR: fail_abstract_var.carbon:[[@LINE+7]]:10: error: binding pattern has abstract type `{.m2: Abstract2}` in `var` pattern [AbstractTypeInVarPattern]
-  // CHECK:STDERR:   var v: {.m2: Abstract2};
-  // CHECK:STDERR:          ^~~~~~~~~~~~~~~~
-  // CHECK:STDERR: fail_abstract_var.carbon:[[@LINE-6]]:1: note: uses class that was declared abstract here [ClassAbstractHere]
-  // CHECK:STDERR: abstract class Abstract2 {}
-  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~
-  // CHECK:STDERR:
-  var v: {.m2: Abstract2};
-}
+// CHECK:STDERR: fail_abstract_var.carbon:[[@LINE+7]]:8: error: binding pattern has abstract type `{.m2: Abstract2}` in `var` pattern [AbstractTypeInVarPattern]
+// CHECK:STDERR: var v: {.m2: Abstract2};
+// CHECK:STDERR:        ^~~~~~~~~~~~~~~~
+// CHECK:STDERR: fail_abstract_var.carbon:[[@LINE-5]]:1: note: uses class that was declared abstract here [ClassAbstractHere]
+// CHECK:STDERR: abstract class Abstract2 {}
+// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~
+// CHECK:STDERR:
+var v: {.m2: Abstract2};
 
 // --- abstract_let.carbon
 library "[[@TEST_NAME]]";
@@ -56,48 +54,42 @@ library "[[@TEST_NAME]]";
 abstract class Abstract4 {}
 abstract class Abstract5 {}
 
-fn Var2() {
-  // CHECK:STDERR: fail_abstract_twice.carbon:[[@LINE+7]]:11: error: binding pattern has abstract type `{.m4: Abstract4, .m5: Abstract5}` in `var` pattern [AbstractTypeInVarPattern]
-  // CHECK:STDERR:   var v2: {.m4: Abstract4, .m5: Abstract5};
-  // CHECK:STDERR:           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-  // CHECK:STDERR: fail_abstract_twice.carbon:[[@LINE-7]]:1: note: uses class that was declared abstract here [ClassAbstractHere]
-  // CHECK:STDERR: abstract class Abstract4 {}
-  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~
-  // CHECK:STDERR:
-  var v2: {.m4: Abstract4, .m5: Abstract5};
-}
+// CHECK:STDERR: fail_abstract_twice.carbon:[[@LINE+7]]:9: error: binding pattern has abstract type `{.m4: Abstract4, .m5: Abstract5}` in `var` pattern [AbstractTypeInVarPattern]
+// CHECK:STDERR: var v2: {.m4: Abstract4, .m5: Abstract5};
+// CHECK:STDERR:         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+// CHECK:STDERR: fail_abstract_twice.carbon:[[@LINE-6]]:1: note: uses class that was declared abstract here [ClassAbstractHere]
+// CHECK:STDERR: abstract class Abstract4 {}
+// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~
+// CHECK:STDERR:
+var v2: {.m4: Abstract4, .m5: Abstract5};
 
 // --- fail_abstract_first.carbon
 library "[[@TEST_NAME]]";
 
 abstract class Abstract6 {}
 
-fn Var3() {
-  // CHECK:STDERR: fail_abstract_first.carbon:[[@LINE+7]]:11: error: binding pattern has abstract type `{.m6: Abstract6, .c1: ()}` in `var` pattern [AbstractTypeInVarPattern]
-  // CHECK:STDERR:   var v3: {.m6: Abstract6, .c1: ()};
-  // CHECK:STDERR:           ^~~~~~~~~~~~~~~~~~~~~~~~~
-  // CHECK:STDERR: fail_abstract_first.carbon:[[@LINE-6]]:1: note: uses class that was declared abstract here [ClassAbstractHere]
-  // CHECK:STDERR: abstract class Abstract6 {}
-  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~
-  // CHECK:STDERR:
-  var v3: {.m6: Abstract6, .c1: ()};
-}
+// CHECK:STDERR: fail_abstract_first.carbon:[[@LINE+7]]:9: error: binding pattern has abstract type `{.m6: Abstract6, .c1: ()}` in `var` pattern [AbstractTypeInVarPattern]
+// CHECK:STDERR: var v3: {.m6: Abstract6, .c1: ()};
+// CHECK:STDERR:         ^~~~~~~~~~~~~~~~~~~~~~~~~
+// CHECK:STDERR: fail_abstract_first.carbon:[[@LINE-5]]:1: note: uses class that was declared abstract here [ClassAbstractHere]
+// CHECK:STDERR: abstract class Abstract6 {}
+// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~
+// CHECK:STDERR:
+var v3: {.m6: Abstract6, .c1: ()};
 
 // --- fail_abstract_second.carbon
 library "[[@TEST_NAME]]";
 
 abstract class Abstract7 {}
 
-fn Var4() {
-  // CHECK:STDERR: fail_abstract_second.carbon:[[@LINE+7]]:11: error: binding pattern has abstract type `{.c2: (), .m7: Abstract7}` in `var` pattern [AbstractTypeInVarPattern]
-  // CHECK:STDERR:   var v4: {.c2: (), .m7: Abstract7};
-  // CHECK:STDERR:           ^~~~~~~~~~~~~~~~~~~~~~~~~
-  // CHECK:STDERR: fail_abstract_second.carbon:[[@LINE-6]]:1: note: uses class that was declared abstract here [ClassAbstractHere]
-  // CHECK:STDERR: abstract class Abstract7 {}
-  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~
-  // CHECK:STDERR:
-  var v4: {.c2: (), .m7: Abstract7};
-}
+// CHECK:STDERR: fail_abstract_second.carbon:[[@LINE+7]]:9: error: binding pattern has abstract type `{.c2: (), .m7: Abstract7}` in `var` pattern [AbstractTypeInVarPattern]
+// CHECK:STDERR: var v4: {.c2: (), .m7: Abstract7};
+// CHECK:STDERR:         ^~~~~~~~~~~~~~~~~~~~~~~~~
+// CHECK:STDERR: fail_abstract_second.carbon:[[@LINE-5]]:1: note: uses class that was declared abstract here [ClassAbstractHere]
+// CHECK:STDERR: abstract class Abstract7 {}
+// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~
+// CHECK:STDERR:
+var v4: {.c2: (), .m7: Abstract7};
 
 // --- lib.carbon
 library "[[@TEST_NAME]]";
@@ -109,17 +101,15 @@ library "[[@TEST_NAME]]";
 
 import library "lib";
 
-fn Var5() {
-  // CHECK:STDERR: fail_import.carbon:[[@LINE+8]]:11: error: binding pattern has abstract type `{.m: Abstract}` in `var` pattern [AbstractTypeInVarPattern]
-  // CHECK:STDERR:   var v5: {.m: Abstract};
-  // CHECK:STDERR:           ^~~~~~~~~~~~~~
-  // CHECK:STDERR: fail_import.carbon:[[@LINE-6]]:1: in import [InImport]
-  // CHECK:STDERR: lib.carbon:3:1: note: uses class that was declared abstract here [ClassAbstractHere]
-  // CHECK:STDERR: abstract class Abstract {}
-  // CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~
-  // CHECK:STDERR:
-  var v5: {.m: Abstract};
-}
+// CHECK:STDERR: fail_import.carbon:[[@LINE+8]]:9: error: binding pattern has abstract type `{.m: Abstract}` in `var` pattern [AbstractTypeInVarPattern]
+// CHECK:STDERR: var v5: {.m: Abstract};
+// CHECK:STDERR:         ^~~~~~~~~~~~~~
+// CHECK:STDERR: fail_import.carbon:[[@LINE-5]]:1: in import [InImport]
+// CHECK:STDERR: lib.carbon:3:1: note: uses class that was declared abstract here [ClassAbstractHere]
+// CHECK:STDERR: abstract class Abstract {}
+// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~
+// CHECK:STDERR:
+var v5: {.m: Abstract};
 
 // CHECK:STDOUT: --- fail_abstract_field.carbon
 // CHECK:STDOUT:
@@ -169,18 +159,25 @@ fn Var5() {
 // CHECK:STDOUT:   %Abstract2: type = class_type @Abstract2 [concrete]
 // CHECK:STDOUT:   %empty_struct_type: type = struct_type {} [concrete]
 // CHECK:STDOUT:   %complete_type: <witness> = complete_type_witness %empty_struct_type [concrete]
-// CHECK:STDOUT:   %Var.type: type = fn_type @Var [concrete]
-// CHECK:STDOUT:   %Var: %Var.type = struct_value () [concrete]
 // CHECK:STDOUT:   %struct_type.m2.155: type = struct_type {.m2: %Abstract2} [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
 // CHECK:STDOUT:     .Abstract2 = %Abstract2.decl
-// CHECK:STDOUT:     .Var = %Var.decl
+// CHECK:STDOUT:     .v = %v
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Abstract2.decl: type = class_decl @Abstract2 [concrete = constants.%Abstract2] {} {}
-// CHECK:STDOUT:   %Var.decl: %Var.type = fn_decl @Var [concrete = constants.%Var] {} {}
+// CHECK:STDOUT:   name_binding_decl {
+// CHECK:STDOUT:     %v.patt: <error> = binding_pattern v
+// CHECK:STDOUT:     %.loc12_1: <error> = var_pattern %v.patt
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %v.var: ref <error> = var v
+// CHECK:STDOUT:   %.loc12_23: type = splice_block %struct_type.m2 [concrete = constants.%struct_type.m2.155] {
+// CHECK:STDOUT:     %Abstract2.ref: type = name_ref Abstract2, %Abstract2.decl [concrete = constants.%Abstract2]
+// CHECK:STDOUT:     %struct_type.m2: type = struct_type {.m2: %Abstract2} [concrete = constants.%struct_type.m2.155]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %v: <error> = bind_name v, <error>
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: class @Abstract2 {
@@ -192,21 +189,6 @@ fn Var5() {
 // CHECK:STDOUT:   .Self = constants.%Abstract2
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: fn @Var() {
-// CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   name_binding_decl {
-// CHECK:STDOUT:     %v.patt: <error> = binding_pattern v
-// CHECK:STDOUT:     %.loc13_3: <error> = var_pattern %v.patt
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %v.var: ref <error> = var v
-// CHECK:STDOUT:   %.loc13_25: type = splice_block %struct_type.m2 [concrete = constants.%struct_type.m2.155] {
-// CHECK:STDOUT:     %Abstract2.ref: type = name_ref Abstract2, file.%Abstract2.decl [concrete = constants.%Abstract2]
-// CHECK:STDOUT:     %struct_type.m2: type = struct_type {.m2: %Abstract2} [concrete = constants.%struct_type.m2.155]
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %v: <error> = bind_name v, <error>
-// CHECK:STDOUT:   return
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
 // CHECK:STDOUT: --- abstract_let.carbon
 // CHECK:STDOUT:
 // CHECK:STDOUT: constants {
@@ -265,8 +247,6 @@ fn Var5() {
 // CHECK:STDOUT:   %empty_struct_type: type = struct_type {} [concrete]
 // CHECK:STDOUT:   %complete_type: <witness> = complete_type_witness %empty_struct_type [concrete]
 // CHECK:STDOUT:   %Abstract5: type = class_type @Abstract5 [concrete]
-// CHECK:STDOUT:   %Var2.type: type = fn_type @Var2 [concrete]
-// CHECK:STDOUT:   %Var2: %Var2.type = struct_value () [concrete]
 // CHECK:STDOUT:   %struct_type.m4.m5.c86: type = struct_type {.m4: %Abstract4, .m5: %Abstract5} [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -274,11 +254,21 @@ fn Var5() {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
 // CHECK:STDOUT:     .Abstract4 = %Abstract4.decl
 // CHECK:STDOUT:     .Abstract5 = %Abstract5.decl
-// CHECK:STDOUT:     .Var2 = %Var2.decl
+// CHECK:STDOUT:     .v2 = %v2
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Abstract4.decl: type = class_decl @Abstract4 [concrete = constants.%Abstract4] {} {}
 // CHECK:STDOUT:   %Abstract5.decl: type = class_decl @Abstract5 [concrete = constants.%Abstract5] {} {}
-// CHECK:STDOUT:   %Var2.decl: %Var2.type = fn_decl @Var2 [concrete = constants.%Var2] {} {}
+// CHECK:STDOUT:   name_binding_decl {
+// CHECK:STDOUT:     %v2.patt: <error> = binding_pattern v2
+// CHECK:STDOUT:     %.loc13_1: <error> = var_pattern %v2.patt
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %v2.var: ref <error> = var v2
+// CHECK:STDOUT:   %.loc13_40: type = splice_block %struct_type.m4.m5 [concrete = constants.%struct_type.m4.m5.c86] {
+// CHECK:STDOUT:     %Abstract4.ref: type = name_ref Abstract4, %Abstract4.decl [concrete = constants.%Abstract4]
+// CHECK:STDOUT:     %Abstract5.ref: type = name_ref Abstract5, %Abstract5.decl [concrete = constants.%Abstract5]
+// CHECK:STDOUT:     %struct_type.m4.m5: type = struct_type {.m4: %Abstract4, .m5: %Abstract5} [concrete = constants.%struct_type.m4.m5.c86]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %v2: <error> = bind_name v2, <error>
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: class @Abstract4 {
@@ -299,41 +289,34 @@ fn Var5() {
 // CHECK:STDOUT:   .Self = constants.%Abstract5
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: fn @Var2() {
-// CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   name_binding_decl {
-// CHECK:STDOUT:     %v2.patt: <error> = binding_pattern v2
-// CHECK:STDOUT:     %.loc14_3: <error> = var_pattern %v2.patt
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %v2.var: ref <error> = var v2
-// CHECK:STDOUT:   %.loc14_42: type = splice_block %struct_type.m4.m5 [concrete = constants.%struct_type.m4.m5.c86] {
-// CHECK:STDOUT:     %Abstract4.ref: type = name_ref Abstract4, file.%Abstract4.decl [concrete = constants.%Abstract4]
-// CHECK:STDOUT:     %Abstract5.ref: type = name_ref Abstract5, file.%Abstract5.decl [concrete = constants.%Abstract5]
-// CHECK:STDOUT:     %struct_type.m4.m5: type = struct_type {.m4: %Abstract4, .m5: %Abstract5} [concrete = constants.%struct_type.m4.m5.c86]
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %v2: <error> = bind_name v2, <error>
-// CHECK:STDOUT:   return
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
 // CHECK:STDOUT: --- fail_abstract_first.carbon
 // CHECK:STDOUT:
 // CHECK:STDOUT: constants {
 // CHECK:STDOUT:   %Abstract6: type = class_type @Abstract6 [concrete]
 // CHECK:STDOUT:   %empty_struct_type: type = struct_type {} [concrete]
 // CHECK:STDOUT:   %complete_type: <witness> = complete_type_witness %empty_struct_type [concrete]
-// CHECK:STDOUT:   %Var3.type: type = fn_type @Var3 [concrete]
 // CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
-// CHECK:STDOUT:   %Var3: %Var3.type = struct_value () [concrete]
 // CHECK:STDOUT:   %struct_type.m6.c1.489: type = struct_type {.m6: %Abstract6, .c1: %empty_tuple.type} [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
 // CHECK:STDOUT:     .Abstract6 = %Abstract6.decl
-// CHECK:STDOUT:     .Var3 = %Var3.decl
+// CHECK:STDOUT:     .v3 = %v3
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Abstract6.decl: type = class_decl @Abstract6 [concrete = constants.%Abstract6] {} {}
-// CHECK:STDOUT:   %Var3.decl: %Var3.type = fn_decl @Var3 [concrete = constants.%Var3] {} {}
+// CHECK:STDOUT:   name_binding_decl {
+// CHECK:STDOUT:     %v3.patt: <error> = binding_pattern v3
+// CHECK:STDOUT:     %.loc12_1: <error> = var_pattern %v3.patt
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %v3.var: ref <error> = var v3
+// CHECK:STDOUT:   %.loc12_33: type = splice_block %struct_type.m6.c1 [concrete = constants.%struct_type.m6.c1.489] {
+// CHECK:STDOUT:     %Abstract6.ref: type = name_ref Abstract6, %Abstract6.decl [concrete = constants.%Abstract6]
+// CHECK:STDOUT:     %.loc12_32.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc12_32.2: type = converted %.loc12_32.1, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:     %struct_type.m6.c1: type = struct_type {.m6: %Abstract6, .c1: %empty_tuple.type} [concrete = constants.%struct_type.m6.c1.489]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %v3: <error> = bind_name v3, <error>
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: class @Abstract6 {
@@ -345,42 +328,34 @@ fn Var5() {
 // CHECK:STDOUT:   .Self = constants.%Abstract6
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: fn @Var3() {
-// CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   name_binding_decl {
-// CHECK:STDOUT:     %v3.patt: <error> = binding_pattern v3
-// CHECK:STDOUT:     %.loc13_3: <error> = var_pattern %v3.patt
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %v3.var: ref <error> = var v3
-// CHECK:STDOUT:   %.loc13_35: type = splice_block %struct_type.m6.c1 [concrete = constants.%struct_type.m6.c1.489] {
-// CHECK:STDOUT:     %Abstract6.ref: type = name_ref Abstract6, file.%Abstract6.decl [concrete = constants.%Abstract6]
-// CHECK:STDOUT:     %.loc13_34.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc13_34.2: type = converted %.loc13_34.1, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
-// CHECK:STDOUT:     %struct_type.m6.c1: type = struct_type {.m6: %Abstract6, .c1: %empty_tuple.type} [concrete = constants.%struct_type.m6.c1.489]
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %v3: <error> = bind_name v3, <error>
-// CHECK:STDOUT:   return
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
 // CHECK:STDOUT: --- fail_abstract_second.carbon
 // CHECK:STDOUT:
 // CHECK:STDOUT: constants {
 // CHECK:STDOUT:   %Abstract7: type = class_type @Abstract7 [concrete]
 // CHECK:STDOUT:   %empty_struct_type: type = struct_type {} [concrete]
 // CHECK:STDOUT:   %complete_type: <witness> = complete_type_witness %empty_struct_type [concrete]
-// CHECK:STDOUT:   %Var4.type: type = fn_type @Var4 [concrete]
 // CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
-// CHECK:STDOUT:   %Var4: %Var4.type = struct_value () [concrete]
 // CHECK:STDOUT:   %struct_type.c2.m7.4a7: type = struct_type {.c2: %empty_tuple.type, .m7: %Abstract7} [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
 // CHECK:STDOUT:     .Abstract7 = %Abstract7.decl
-// CHECK:STDOUT:     .Var4 = %Var4.decl
+// CHECK:STDOUT:     .v4 = %v4
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Abstract7.decl: type = class_decl @Abstract7 [concrete = constants.%Abstract7] {} {}
-// CHECK:STDOUT:   %Var4.decl: %Var4.type = fn_decl @Var4 [concrete = constants.%Var4] {} {}
+// CHECK:STDOUT:   name_binding_decl {
+// CHECK:STDOUT:     %v4.patt: <error> = binding_pattern v4
+// CHECK:STDOUT:     %.loc12_1: <error> = var_pattern %v4.patt
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %v4.var: ref <error> = var v4
+// CHECK:STDOUT:   %.loc12_33: type = splice_block %struct_type.c2.m7 [concrete = constants.%struct_type.c2.m7.4a7] {
+// CHECK:STDOUT:     %.loc12_16.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc12_16.2: type = converted %.loc12_16.1, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:     %Abstract7.ref: type = name_ref Abstract7, %Abstract7.decl [concrete = constants.%Abstract7]
+// CHECK:STDOUT:     %struct_type.c2.m7: type = struct_type {.c2: %empty_tuple.type, .m7: %Abstract7} [concrete = constants.%struct_type.c2.m7.4a7]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %v4: <error> = bind_name v4, <error>
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: class @Abstract7 {
@@ -392,23 +367,6 @@ fn Var5() {
 // CHECK:STDOUT:   .Self = constants.%Abstract7
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: fn @Var4() {
-// CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   name_binding_decl {
-// CHECK:STDOUT:     %v4.patt: <error> = binding_pattern v4
-// CHECK:STDOUT:     %.loc13_3: <error> = var_pattern %v4.patt
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %v4.var: ref <error> = var v4
-// CHECK:STDOUT:   %.loc13_35: type = splice_block %struct_type.c2.m7 [concrete = constants.%struct_type.c2.m7.4a7] {
-// CHECK:STDOUT:     %.loc13_18.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc13_18.2: type = converted %.loc13_18.1, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
-// CHECK:STDOUT:     %Abstract7.ref: type = name_ref Abstract7, file.%Abstract7.decl [concrete = constants.%Abstract7]
-// CHECK:STDOUT:     %struct_type.c2.m7: type = struct_type {.c2: %empty_tuple.type, .m7: %Abstract7} [concrete = constants.%struct_type.c2.m7.4a7]
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %v4: <error> = bind_name v4, <error>
-// CHECK:STDOUT:   return
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
 // CHECK:STDOUT: --- lib.carbon
 // CHECK:STDOUT:
 // CHECK:STDOUT: constants {
@@ -436,8 +394,6 @@ fn Var5() {
 // CHECK:STDOUT: --- fail_import.carbon
 // CHECK:STDOUT:
 // CHECK:STDOUT: constants {
-// CHECK:STDOUT:   %Var5.type: type = fn_type @Var5 [concrete]
-// CHECK:STDOUT:   %Var5: %Var5.type = struct_value () [concrete]
 // CHECK:STDOUT:   %Abstract: type = class_type @Abstract [concrete]
 // CHECK:STDOUT:   %empty_struct_type: type = struct_type {} [concrete]
 // CHECK:STDOUT:   %complete_type: <witness> = complete_type_witness %empty_struct_type [concrete]
@@ -453,10 +409,19 @@ fn Var5() {
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
 // CHECK:STDOUT:     .Abstract = imports.%Main.Abstract
-// CHECK:STDOUT:     .Var5 = %Var5.decl
+// CHECK:STDOUT:     .v5 = %v5
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %default.import = import <none>
-// CHECK:STDOUT:   %Var5.decl: %Var5.type = fn_decl @Var5 [concrete = constants.%Var5] {} {}
+// CHECK:STDOUT:   name_binding_decl {
+// CHECK:STDOUT:     %v5.patt: <error> = binding_pattern v5
+// CHECK:STDOUT:     %.loc13_1: <error> = var_pattern %v5.patt
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %v5.var: ref <error> = var v5
+// CHECK:STDOUT:   %.loc13_22: type = splice_block %struct_type.m [concrete = constants.%struct_type.m.50b] {
+// CHECK:STDOUT:     %Abstract.ref: type = name_ref Abstract, imports.%Main.Abstract [concrete = constants.%Abstract]
+// CHECK:STDOUT:     %struct_type.m: type = struct_type {.m: %Abstract} [concrete = constants.%struct_type.m.50b]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %v5: <error> = bind_name v5, <error>
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: class @Abstract [from "lib.carbon"] {
@@ -466,18 +431,3 @@ fn Var5() {
 // CHECK:STDOUT:   .Self = imports.%Main.import_ref.ee1
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: fn @Var5() {
-// CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   name_binding_decl {
-// CHECK:STDOUT:     %v5.patt: <error> = binding_pattern v5
-// CHECK:STDOUT:     %.loc14_3: <error> = var_pattern %v5.patt
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %v5.var: ref <error> = var v5
-// CHECK:STDOUT:   %.loc14_24: type = splice_block %struct_type.m [concrete = constants.%struct_type.m.50b] {
-// CHECK:STDOUT:     %Abstract.ref: type = name_ref Abstract, imports.%Main.Abstract [concrete = constants.%Abstract]
-// CHECK:STDOUT:     %struct_type.m: type = struct_type {.m: %Abstract} [concrete = constants.%struct_type.m.50b]
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %v5: <error> = bind_name v5, <error>
-// CHECK:STDOUT:   return
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/function/call/no_prelude/alias.carbon b/toolchain/check/testdata/function/call/min_prelude/alias.carbon
similarity index 68%
rename from toolchain/check/testdata/function/call/no_prelude/alias.carbon
rename to toolchain/check/testdata/function/call/min_prelude/alias.carbon
index e8d4501535bb..03ba66348730 100644
--- a/toolchain/check/testdata/function/call/no_prelude/alias.carbon
+++ b/toolchain/check/testdata/function/call/min_prelude/alias.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/function/call/no_prelude/alias.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/function/call/min_prelude/alias.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/call/no_prelude/alias.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/call/min_prelude/alias.carbon
 
 fn A() -> () { return (); }
 
@@ -27,18 +30,26 @@ fn Main() {
 // CHECK:STDOUT:   %Main: %Main.type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .A = %A.decl
 // CHECK:STDOUT:     .B = %B
 // CHECK:STDOUT:     .Main = %Main.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %A.decl: %A.type = fn_decl @A [concrete = constants.%A] {
 // CHECK:STDOUT:     %return.patt: %empty_tuple.type = return_slot_pattern
 // CHECK:STDOUT:     %return.param_patt: %empty_tuple.type = out_param_pattern %return.patt, call_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %.loc11_12.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc11_12.2: type = converted %.loc11_12.1, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:     %.loc14_12.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc14_12.2: type = converted %.loc14_12.1, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
 // CHECK:STDOUT:     %return.param: ref %empty_tuple.type = out_param call_param0
 // CHECK:STDOUT:     %return: ref %empty_tuple.type = return_slot %return.param
 // CHECK:STDOUT:   }
@@ -49,27 +60,33 @@ fn Main() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @A() -> %empty_tuple.type {
 // CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   %.loc11_24: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:   %.loc14_24: %empty_tuple.type = tuple_literal ()
 // CHECK:STDOUT:   %empty_tuple: %empty_tuple.type = tuple_value () [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   %.loc11_25: %empty_tuple.type = converted %.loc11_24, %empty_tuple [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   return %.loc11_25
+// CHECK:STDOUT:   %.loc14_25: %empty_tuple.type = converted %.loc14_24, %empty_tuple [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   return %.loc14_25
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @Main() {
 // CHECK:STDOUT: !entry:
 // CHECK:STDOUT:   name_binding_decl {
 // CHECK:STDOUT:     %b.patt: %empty_tuple.type = binding_pattern b
-// CHECK:STDOUT:     %.loc16_3: %empty_tuple.type = var_pattern %b.patt
+// CHECK:STDOUT:     %.loc19_3: %empty_tuple.type = var_pattern %b.patt
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %b.var: ref %empty_tuple.type = var b
 // CHECK:STDOUT:   %B.ref: %A.type = name_ref B, file.%B [concrete = constants.%A]
 // CHECK:STDOUT:   %A.call: init %empty_tuple.type = call %B.ref()
 // CHECK:STDOUT:   assign %b.var, %A.call
-// CHECK:STDOUT:   %.loc16_11.1: type = splice_block %.loc16_11.3 [concrete = constants.%empty_tuple.type] {
-// CHECK:STDOUT:     %.loc16_11.2: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc16_11.3: type = converted %.loc16_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:   %.loc19_11.1: type = splice_block %.loc19_11.3 [concrete = constants.%empty_tuple.type] {
+// CHECK:STDOUT:     %.loc19_11.2: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc19_11.3: type = converted %.loc19_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %b: ref %empty_tuple.type = bind_name b, %b.var
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/function/call/no_prelude/return_implicit.carbon b/toolchain/check/testdata/function/call/min_prelude/return_implicit.carbon
similarity index 71%
rename from toolchain/check/testdata/function/call/no_prelude/return_implicit.carbon
rename to toolchain/check/testdata/function/call/min_prelude/return_implicit.carbon
index 8fa806e066de..6baf7d799ef0 100644
--- a/toolchain/check/testdata/function/call/no_prelude/return_implicit.carbon
+++ b/toolchain/check/testdata/function/call/min_prelude/return_implicit.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/function/call/no_prelude/return_implicit.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/function/call/min_prelude/return_implicit.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/call/no_prelude/return_implicit.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/call/min_prelude/return_implicit.carbon
 
 fn MakeImplicitEmptyTuple() {
 }
@@ -25,11 +28,19 @@ fn Main() {
 // CHECK:STDOUT:   %Main: %Main.type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .MakeImplicitEmptyTuple = %MakeImplicitEmptyTuple.decl
 // CHECK:STDOUT:     .Main = %Main.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %MakeImplicitEmptyTuple.decl: %MakeImplicitEmptyTuple.type = fn_decl @MakeImplicitEmptyTuple [concrete = constants.%MakeImplicitEmptyTuple] {} {}
 // CHECK:STDOUT:   %Main.decl: %Main.type = fn_decl @Main [concrete = constants.%Main] {} {}
 // CHECK:STDOUT: }
@@ -43,17 +54,23 @@ fn Main() {
 // CHECK:STDOUT: !entry:
 // CHECK:STDOUT:   name_binding_decl {
 // CHECK:STDOUT:     %b.patt: %empty_tuple.type = binding_pattern b
-// CHECK:STDOUT:     %.loc15_3: %empty_tuple.type = var_pattern %b.patt
+// CHECK:STDOUT:     %.loc18_3: %empty_tuple.type = var_pattern %b.patt
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %b.var: ref %empty_tuple.type = var b
 // CHECK:STDOUT:   %MakeImplicitEmptyTuple.ref: %MakeImplicitEmptyTuple.type = name_ref MakeImplicitEmptyTuple, file.%MakeImplicitEmptyTuple.decl [concrete = constants.%MakeImplicitEmptyTuple]
 // CHECK:STDOUT:   %MakeImplicitEmptyTuple.call: init %empty_tuple.type = call %MakeImplicitEmptyTuple.ref()
 // CHECK:STDOUT:   assign %b.var, %MakeImplicitEmptyTuple.call
-// CHECK:STDOUT:   %.loc15_11.1: type = splice_block %.loc15_11.3 [concrete = constants.%empty_tuple.type] {
-// CHECK:STDOUT:     %.loc15_11.2: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc15_11.3: type = converted %.loc15_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:   %.loc18_11.1: type = splice_block %.loc18_11.3 [concrete = constants.%empty_tuple.type] {
+// CHECK:STDOUT:     %.loc18_11.2: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc18_11.3: type = converted %.loc18_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %b: ref %empty_tuple.type = bind_name b, %b.var
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/function/declaration/no_prelude/fail_import_incomplete_return.carbon b/toolchain/check/testdata/function/declaration/min_prelude/fail_import_incomplete_return.carbon
similarity index 92%
rename from toolchain/check/testdata/function/declaration/no_prelude/fail_import_incomplete_return.carbon
rename to toolchain/check/testdata/function/declaration/min_prelude/fail_import_incomplete_return.carbon
index bc63764e0acc..d02492b23d7a 100644
--- a/toolchain/check/testdata/function/declaration/no_prelude/fail_import_incomplete_return.carbon
+++ b/toolchain/check/testdata/function/declaration/min_prelude/fail_import_incomplete_return.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/function/declaration/no_prelude/fail_import_incomplete_return.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/function/declaration/min_prelude/fail_import_incomplete_return.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/declaration/no_prelude/fail_import_incomplete_return.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/declaration/min_prelude/fail_import_incomplete_return.carbon
 
 // --- fail_incomplete_return.carbon
 
@@ -103,8 +106,15 @@ fn CallFAndGIncomplete() {
 // CHECK:STDOUT:   %complete_type: <witness> = complete_type_witness %empty_struct_type [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .C = %C.decl
 // CHECK:STDOUT:     .D = %D.decl.loc5
 // CHECK:STDOUT:     .ReturnCUnused = %ReturnCUnused.decl
@@ -113,6 +123,7 @@ fn CallFAndGIncomplete() {
 // CHECK:STDOUT:     .ReturnDUsed = %ReturnDUsed.decl
 // CHECK:STDOUT:     .Call = %Call.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %C.decl: type = class_decl @C [concrete = constants.%C] {} {}
 // CHECK:STDOUT:   %D.decl.loc5: type = class_decl @D [concrete = constants.%D] {} {}
 // CHECK:STDOUT:   %ReturnCUnused.decl: %ReturnCUnused.type = fn_decl @ReturnCUnused [concrete = constants.%ReturnCUnused] {
@@ -205,8 +216,11 @@ fn CallFAndGIncomplete() {
 // CHECK:STDOUT:   %Main.ReturnDUnused: %ReturnDUnused.type = import_ref Main//incomplete_return, ReturnDUnused, loaded [concrete = constants.%ReturnDUnused]
 // CHECK:STDOUT:   %Main.ReturnDUsed: %ReturnDUsed.type = import_ref Main//incomplete_return, ReturnDUsed, loaded [concrete = constants.%ReturnDUsed]
 // CHECK:STDOUT:   %Main.Call = import_ref Main//incomplete_return, Call, unloaded
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Main.import_ref.8f2: <witness> = import_ref Main//incomplete_return, loc37_10, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %Main.import_ref.cab = import_ref Main//incomplete_return, inst18 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.cab = import_ref Main//incomplete_return, inst20 [no loc], unloaded
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
@@ -218,8 +232,10 @@ fn CallFAndGIncomplete() {
 // CHECK:STDOUT:     .ReturnDUnused = imports.%Main.ReturnDUnused
 // CHECK:STDOUT:     .ReturnDUsed = imports.%Main.ReturnDUsed
 // CHECK:STDOUT:     .Call = imports.%Main.Call
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .CallFAndGIncomplete = %CallFAndGIncomplete.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %default.import = import <none>
 // CHECK:STDOUT:   %CallFAndGIncomplete.decl: %CallFAndGIncomplete.type = fn_decl @CallFAndGIncomplete [concrete = constants.%CallFAndGIncomplete] {} {}
 // CHECK:STDOUT: }
@@ -258,3 +274,9 @@ fn CallFAndGIncomplete() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @ReturnDUsed [from "fail_incomplete_return.carbon"];
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/function/definition/no_prelude/fail_local_decl.carbon b/toolchain/check/testdata/function/definition/min_prelude/fail_local_decl.carbon
similarity index 82%
rename from toolchain/check/testdata/function/definition/no_prelude/fail_local_decl.carbon
rename to toolchain/check/testdata/function/definition/min_prelude/fail_local_decl.carbon
index 89f5cd3b72e8..b03bb1c66b0a 100644
--- a/toolchain/check/testdata/function/definition/no_prelude/fail_local_decl.carbon
+++ b/toolchain/check/testdata/function/definition/min_prelude/fail_local_decl.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/function/definition/no_prelude/fail_local_decl.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/function/definition/min_prelude/fail_local_decl.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/definition/no_prelude/fail_local_decl.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/definition/min_prelude/fail_local_decl.carbon
 
 // --- fail_virtual.carbon
 
@@ -60,10 +63,18 @@ fn F() {
 // CHECK:STDOUT:   %H: %H.type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %F.decl: %F.type.b25 = fn_decl @F.1 [concrete = constants.%F.c41] {} {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -89,10 +100,18 @@ fn F() {
 // CHECK:STDOUT:   %empty_struct_type: type = struct_type {} [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -121,3 +140,9 @@ fn F() {
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/function/generic/no_prelude/call.carbon b/toolchain/check/testdata/function/generic/min_prelude/call.carbon
similarity index 96%
rename from toolchain/check/testdata/function/generic/no_prelude/call.carbon
rename to toolchain/check/testdata/function/generic/min_prelude/call.carbon
index 2dd82d9dbbe7..7393ab82a69e 100644
--- a/toolchain/check/testdata/function/generic/no_prelude/call.carbon
+++ b/toolchain/check/testdata/function/generic/min_prelude/call.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/function/generic/no_prelude/call.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/function/generic/min_prelude/call.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/generic/no_prelude/call.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/generic/min_prelude/call.carbon
 
 // --- explicit.carbon
 
@@ -76,14 +79,22 @@ fn CallSpecific(x: C) -> C {
 // CHECK:STDOUT:   %Function.specific_fn.1b5: <specific function> = specific_function %Function, @Function(%C) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Function = %Function.decl
 // CHECK:STDOUT:     .CallGeneric = %CallGeneric.decl
 // CHECK:STDOUT:     .CallGenericPtr = %CallGenericPtr.decl
 // CHECK:STDOUT:     .C = %C.decl
 // CHECK:STDOUT:     .CallSpecific = %CallSpecific.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Function.decl: %Function.type = fn_decl @Function [concrete = constants.%Function] {
 // CHECK:STDOUT:     %T.patt.loc4_13.1: type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc4_13.2 (constants.%T.patt)]
 // CHECK:STDOUT:     %x.patt: @Function.%T.loc4_13.2 (%T) = binding_pattern x
@@ -290,14 +301,22 @@ fn CallSpecific(x: C) -> C {
 // CHECK:STDOUT:   %Function.specific_fn.1b5: <specific function> = specific_function %Function, @Function(%C) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Function = %Function.decl
 // CHECK:STDOUT:     .CallGeneric = %CallGeneric.decl
 // CHECK:STDOUT:     .CallGenericPtr = %CallGenericPtr.decl
 // CHECK:STDOUT:     .C = %C.decl
 // CHECK:STDOUT:     .CallSpecific = %CallSpecific.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Function.decl: %Function.type = fn_decl @Function [concrete = constants.%Function] {
 // CHECK:STDOUT:     %T.patt.loc4_13.1: type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc4_13.2 (constants.%T.patt)]
 // CHECK:STDOUT:     %x.patt: @Function.%T.loc4_13.2 (%T) = binding_pattern x
@@ -476,3 +495,9 @@ fn CallSpecific(x: C) -> C {
 // CHECK:STDOUT:   %require_complete => constants.%complete_type
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/function/generic/min_prelude/fail_type_param_mismatch.carbon b/toolchain/check/testdata/function/generic/min_prelude/fail_type_param_mismatch.carbon
new file mode 100644
index 000000000000..1c70700cfc26
--- /dev/null
+++ b/toolchain/check/testdata/function/generic/min_prelude/fail_type_param_mismatch.carbon
@@ -0,0 +1,107 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
+// AUTOUPDATE
+// TIP: To test this file alone, run:
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/function/generic/min_prelude/fail_type_param_mismatch.carbon
+// TIP: To dump output, run:
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/generic/min_prelude/fail_type_param_mismatch.carbon
+
+fn F(T:! type, U:! type) {
+  var p: T*;
+  // CHECK:STDERR: fail_type_param_mismatch.carbon:[[@LINE+4]]:14: error: name `Core.ImplicitAs` implicitly referenced here, but not found [CoreNameNotFound]
+  // CHECK:STDERR:   let n: U = *p;
+  // CHECK:STDERR:              ^~
+  // CHECK:STDERR:
+  let n: U = *p;
+}
+
+// CHECK:STDOUT: --- fail_type_param_mismatch.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: constants {
+// CHECK:STDOUT:   %T: type = bind_symbolic_name T, 0 [symbolic]
+// CHECK:STDOUT:   %T.patt: type = symbolic_binding_pattern T, 0 [symbolic]
+// CHECK:STDOUT:   %U: type = bind_symbolic_name U, 1 [symbolic]
+// CHECK:STDOUT:   %U.patt: type = symbolic_binding_pattern U, 1 [symbolic]
+// CHECK:STDOUT:   %F.type: type = fn_type @F [concrete]
+// CHECK:STDOUT:   %F: %F.type = struct_value () [concrete]
+// CHECK:STDOUT:   %ptr: type = ptr_type %T [symbolic]
+// CHECK:STDOUT:   %require_complete.6e5: <witness> = require_complete_type %ptr [symbolic]
+// CHECK:STDOUT:   %require_complete.b54: <witness> = require_complete_type %U [symbolic]
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     .ImplicitAs = <poisoned>
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
+// CHECK:STDOUT:     .F = %F.decl
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
+// CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {
+// CHECK:STDOUT:     %T.patt.loc14_6.1: type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc14_6.2 (constants.%T.patt)]
+// CHECK:STDOUT:     %U.patt.loc14_16.1: type = symbolic_binding_pattern U, 1 [symbolic = %U.patt.loc14_16.2 (constants.%U.patt)]
+// CHECK:STDOUT:   } {
+// CHECK:STDOUT:     %T.loc14_6.1: type = bind_symbolic_name T, 0 [symbolic = %T.loc14_6.2 (constants.%T)]
+// CHECK:STDOUT:     %U.loc14_16.1: type = bind_symbolic_name U, 1 [symbolic = %U.loc14_16.2 (constants.%U)]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: generic fn @F(%T.loc14_6.1: type, %U.loc14_16.1: type) {
+// CHECK:STDOUT:   %T.loc14_6.2: type = bind_symbolic_name T, 0 [symbolic = %T.loc14_6.2 (constants.%T)]
+// CHECK:STDOUT:   %T.patt.loc14_6.2: type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc14_6.2 (constants.%T.patt)]
+// CHECK:STDOUT:   %U.loc14_16.2: type = bind_symbolic_name U, 1 [symbolic = %U.loc14_16.2 (constants.%U)]
+// CHECK:STDOUT:   %U.patt.loc14_16.2: type = symbolic_binding_pattern U, 1 [symbolic = %U.patt.loc14_16.2 (constants.%U.patt)]
+// CHECK:STDOUT:
+// CHECK:STDOUT: !definition:
+// CHECK:STDOUT:   %ptr.loc15_11.2: type = ptr_type %T.loc14_6.2 [symbolic = %ptr.loc15_11.2 (constants.%ptr)]
+// CHECK:STDOUT:   %require_complete.loc15: <witness> = require_complete_type %ptr.loc15_11.2 [symbolic = %require_complete.loc15 (constants.%require_complete.6e5)]
+// CHECK:STDOUT:   %require_complete.loc20: <witness> = require_complete_type %U.loc14_16.2 [symbolic = %require_complete.loc20 (constants.%require_complete.b54)]
+// CHECK:STDOUT:
+// CHECK:STDOUT:   fn() {
+// CHECK:STDOUT:   !entry:
+// CHECK:STDOUT:     name_binding_decl {
+// CHECK:STDOUT:       %p.patt: @F.%ptr.loc15_11.2 (%ptr) = binding_pattern p
+// CHECK:STDOUT:       %.loc15_3: @F.%ptr.loc15_11.2 (%ptr) = var_pattern %p.patt
+// CHECK:STDOUT:     }
+// CHECK:STDOUT:     %p.var: ref @F.%ptr.loc15_11.2 (%ptr) = var p
+// CHECK:STDOUT:     %.loc15_11: type = splice_block %ptr.loc15_11.1 [symbolic = %ptr.loc15_11.2 (constants.%ptr)] {
+// CHECK:STDOUT:       %T.ref: type = name_ref T, %T.loc14_6.1 [symbolic = %T.loc14_6.2 (constants.%T)]
+// CHECK:STDOUT:       %ptr.loc15_11.1: type = ptr_type %T.ref [symbolic = %ptr.loc15_11.2 (constants.%ptr)]
+// CHECK:STDOUT:     }
+// CHECK:STDOUT:     %p: ref @F.%ptr.loc15_11.2 (%ptr) = bind_name p, %p.var
+// CHECK:STDOUT:     name_binding_decl {
+// CHECK:STDOUT:       %n.patt: @F.%U.loc14_16.2 (%U) = binding_pattern n
+// CHECK:STDOUT:     }
+// CHECK:STDOUT:     %p.ref: ref @F.%ptr.loc15_11.2 (%ptr) = name_ref p, %p
+// CHECK:STDOUT:     %.loc20_15: @F.%ptr.loc15_11.2 (%ptr) = bind_value %p.ref
+// CHECK:STDOUT:     %.loc20_14.1: ref @F.%T.loc14_6.2 (%T) = deref %.loc20_15
+// CHECK:STDOUT:     %U.ref: type = name_ref U, %U.loc14_16.1 [symbolic = %U.loc14_16.2 (constants.%U)]
+// CHECK:STDOUT:     %.loc20_14.2: @F.%U.loc14_16.2 (%U) = converted %.loc20_14.1, <error> [concrete = <error>]
+// CHECK:STDOUT:     %n: @F.%U.loc14_16.2 (%U) = bind_name n, <error>
+// CHECK:STDOUT:     return
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: specific @F(constants.%T, constants.%U) {
+// CHECK:STDOUT:   %T.loc14_6.2 => constants.%T
+// CHECK:STDOUT:   %T.patt.loc14_6.2 => constants.%T.patt
+// CHECK:STDOUT:   %U.loc14_16.2 => constants.%U
+// CHECK:STDOUT:   %U.patt.loc14_16.2 => constants.%U.patt
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/function/generic/min_prelude/type_param.carbon b/toolchain/check/testdata/function/generic/min_prelude/type_param.carbon
new file mode 100644
index 000000000000..e2cfeb165d9d
--- /dev/null
+++ b/toolchain/check/testdata/function/generic/min_prelude/type_param.carbon
@@ -0,0 +1,93 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
+// AUTOUPDATE
+// TIP: To test this file alone, run:
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/function/generic/min_prelude/type_param.carbon
+// TIP: To dump output, run:
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/generic/min_prelude/type_param.carbon
+
+fn F(T:! type) {
+  var p: T*;
+  let n: T = *p;
+}
+
+// CHECK:STDOUT: --- type_param.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: constants {
+// CHECK:STDOUT:   %T: type = bind_symbolic_name T, 0 [symbolic]
+// CHECK:STDOUT:   %T.patt: type = symbolic_binding_pattern T, 0 [symbolic]
+// CHECK:STDOUT:   %F.type: type = fn_type @F [concrete]
+// CHECK:STDOUT:   %F: %F.type = struct_value () [concrete]
+// CHECK:STDOUT:   %ptr: type = ptr_type %T [symbolic]
+// CHECK:STDOUT:   %require_complete.6e5: <witness> = require_complete_type %ptr [symbolic]
+// CHECK:STDOUT:   %require_complete.4ae: <witness> = require_complete_type %T [symbolic]
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
+// CHECK:STDOUT:     .F = %F.decl
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
+// CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {
+// CHECK:STDOUT:     %T.patt.loc14_6.1: type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc14_6.2 (constants.%T.patt)]
+// CHECK:STDOUT:   } {
+// CHECK:STDOUT:     %T.loc14_6.1: type = bind_symbolic_name T, 0 [symbolic = %T.loc14_6.2 (constants.%T)]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: generic fn @F(%T.loc14_6.1: type) {
+// CHECK:STDOUT:   %T.loc14_6.2: type = bind_symbolic_name T, 0 [symbolic = %T.loc14_6.2 (constants.%T)]
+// CHECK:STDOUT:   %T.patt.loc14_6.2: type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc14_6.2 (constants.%T.patt)]
+// CHECK:STDOUT:
+// CHECK:STDOUT: !definition:
+// CHECK:STDOUT:   %ptr.loc15_11.2: type = ptr_type %T.loc14_6.2 [symbolic = %ptr.loc15_11.2 (constants.%ptr)]
+// CHECK:STDOUT:   %require_complete.loc15: <witness> = require_complete_type %ptr.loc15_11.2 [symbolic = %require_complete.loc15 (constants.%require_complete.6e5)]
+// CHECK:STDOUT:   %require_complete.loc16: <witness> = require_complete_type %T.loc14_6.2 [symbolic = %require_complete.loc16 (constants.%require_complete.4ae)]
+// CHECK:STDOUT:
+// CHECK:STDOUT:   fn() {
+// CHECK:STDOUT:   !entry:
+// CHECK:STDOUT:     name_binding_decl {
+// CHECK:STDOUT:       %p.patt: @F.%ptr.loc15_11.2 (%ptr) = binding_pattern p
+// CHECK:STDOUT:       %.loc15_3: @F.%ptr.loc15_11.2 (%ptr) = var_pattern %p.patt
+// CHECK:STDOUT:     }
+// CHECK:STDOUT:     %p.var: ref @F.%ptr.loc15_11.2 (%ptr) = var p
+// CHECK:STDOUT:     %.loc15_11: type = splice_block %ptr.loc15_11.1 [symbolic = %ptr.loc15_11.2 (constants.%ptr)] {
+// CHECK:STDOUT:       %T.ref.loc15: type = name_ref T, %T.loc14_6.1 [symbolic = %T.loc14_6.2 (constants.%T)]
+// CHECK:STDOUT:       %ptr.loc15_11.1: type = ptr_type %T.ref.loc15 [symbolic = %ptr.loc15_11.2 (constants.%ptr)]
+// CHECK:STDOUT:     }
+// CHECK:STDOUT:     %p: ref @F.%ptr.loc15_11.2 (%ptr) = bind_name p, %p.var
+// CHECK:STDOUT:     name_binding_decl {
+// CHECK:STDOUT:       %n.patt: @F.%T.loc14_6.2 (%T) = binding_pattern n
+// CHECK:STDOUT:     }
+// CHECK:STDOUT:     %p.ref: ref @F.%ptr.loc15_11.2 (%ptr) = name_ref p, %p
+// CHECK:STDOUT:     %.loc16_15: @F.%ptr.loc15_11.2 (%ptr) = bind_value %p.ref
+// CHECK:STDOUT:     %.loc16_14: ref @F.%T.loc14_6.2 (%T) = deref %.loc16_15
+// CHECK:STDOUT:     %T.ref.loc16: type = name_ref T, %T.loc14_6.1 [symbolic = %T.loc14_6.2 (constants.%T)]
+// CHECK:STDOUT:     %n: ref @F.%T.loc14_6.2 (%T) = bind_name n, %.loc16_14
+// CHECK:STDOUT:     return
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: specific @F(constants.%T) {
+// CHECK:STDOUT:   %T.loc14_6.2 => constants.%T
+// CHECK:STDOUT:   %T.patt.loc14_6.2 => constants.%T.patt
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/function/generic/no_prelude/fail_type_param_mismatch.carbon b/toolchain/check/testdata/function/generic/no_prelude/fail_type_param_mismatch.carbon
deleted file mode 100644
index 7627516cab56..000000000000
--- a/toolchain/check/testdata/function/generic/no_prelude/fail_type_param_mismatch.carbon
+++ /dev/null
@@ -1,89 +0,0 @@
-// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
-// Exceptions. See /LICENSE for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-// AUTOUPDATE
-// TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/function/generic/no_prelude/fail_type_param_mismatch.carbon
-// TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/generic/no_prelude/fail_type_param_mismatch.carbon
-
-fn F(T:! type, U:! type) {
-  var p: T*;
-  // CHECK:STDERR: fail_type_param_mismatch.carbon:[[@LINE+4]]:14: error: `Core.ImplicitAs` implicitly referenced here, but package `Core` not found [CoreNotFound]
-  // CHECK:STDERR:   let n: U = *p;
-  // CHECK:STDERR:              ^~
-  // CHECK:STDERR:
-  let n: U = *p;
-}
-
-// CHECK:STDOUT: --- fail_type_param_mismatch.carbon
-// CHECK:STDOUT:
-// CHECK:STDOUT: constants {
-// CHECK:STDOUT:   %T: type = bind_symbolic_name T, 0 [symbolic]
-// CHECK:STDOUT:   %T.patt: type = symbolic_binding_pattern T, 0 [symbolic]
-// CHECK:STDOUT:   %U: type = bind_symbolic_name U, 1 [symbolic]
-// CHECK:STDOUT:   %U.patt: type = symbolic_binding_pattern U, 1 [symbolic]
-// CHECK:STDOUT:   %F.type: type = fn_type @F [concrete]
-// CHECK:STDOUT:   %F: %F.type = struct_value () [concrete]
-// CHECK:STDOUT:   %ptr: type = ptr_type %T [symbolic]
-// CHECK:STDOUT:   %require_complete.6e5: <witness> = require_complete_type %ptr [symbolic]
-// CHECK:STDOUT:   %require_complete.b54: <witness> = require_complete_type %U [symbolic]
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: file {
-// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
-// CHECK:STDOUT:     .F = %F.decl
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {
-// CHECK:STDOUT:     %T.patt.loc11_6.1: type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc11_6.2 (constants.%T.patt)]
-// CHECK:STDOUT:     %U.patt.loc11_16.1: type = symbolic_binding_pattern U, 1 [symbolic = %U.patt.loc11_16.2 (constants.%U.patt)]
-// CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %T.loc11_6.1: type = bind_symbolic_name T, 0 [symbolic = %T.loc11_6.2 (constants.%T)]
-// CHECK:STDOUT:     %U.loc11_16.1: type = bind_symbolic_name U, 1 [symbolic = %U.loc11_16.2 (constants.%U)]
-// CHECK:STDOUT:   }
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: generic fn @F(%T.loc11_6.1: type, %U.loc11_16.1: type) {
-// CHECK:STDOUT:   %T.loc11_6.2: type = bind_symbolic_name T, 0 [symbolic = %T.loc11_6.2 (constants.%T)]
-// CHECK:STDOUT:   %T.patt.loc11_6.2: type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc11_6.2 (constants.%T.patt)]
-// CHECK:STDOUT:   %U.loc11_16.2: type = bind_symbolic_name U, 1 [symbolic = %U.loc11_16.2 (constants.%U)]
-// CHECK:STDOUT:   %U.patt.loc11_16.2: type = symbolic_binding_pattern U, 1 [symbolic = %U.patt.loc11_16.2 (constants.%U.patt)]
-// CHECK:STDOUT:
-// CHECK:STDOUT: !definition:
-// CHECK:STDOUT:   %ptr.loc12_11.2: type = ptr_type %T.loc11_6.2 [symbolic = %ptr.loc12_11.2 (constants.%ptr)]
-// CHECK:STDOUT:   %require_complete.loc12: <witness> = require_complete_type %ptr.loc12_11.2 [symbolic = %require_complete.loc12 (constants.%require_complete.6e5)]
-// CHECK:STDOUT:   %require_complete.loc17: <witness> = require_complete_type %U.loc11_16.2 [symbolic = %require_complete.loc17 (constants.%require_complete.b54)]
-// CHECK:STDOUT:
-// CHECK:STDOUT:   fn() {
-// CHECK:STDOUT:   !entry:
-// CHECK:STDOUT:     name_binding_decl {
-// CHECK:STDOUT:       %p.patt: @F.%ptr.loc12_11.2 (%ptr) = binding_pattern p
-// CHECK:STDOUT:       %.loc12_3: @F.%ptr.loc12_11.2 (%ptr) = var_pattern %p.patt
-// CHECK:STDOUT:     }
-// CHECK:STDOUT:     %p.var: ref @F.%ptr.loc12_11.2 (%ptr) = var p
-// CHECK:STDOUT:     %.loc12_11: type = splice_block %ptr.loc12_11.1 [symbolic = %ptr.loc12_11.2 (constants.%ptr)] {
-// CHECK:STDOUT:       %T.ref: type = name_ref T, %T.loc11_6.1 [symbolic = %T.loc11_6.2 (constants.%T)]
-// CHECK:STDOUT:       %ptr.loc12_11.1: type = ptr_type %T.ref [symbolic = %ptr.loc12_11.2 (constants.%ptr)]
-// CHECK:STDOUT:     }
-// CHECK:STDOUT:     %p: ref @F.%ptr.loc12_11.2 (%ptr) = bind_name p, %p.var
-// CHECK:STDOUT:     name_binding_decl {
-// CHECK:STDOUT:       %n.patt: @F.%U.loc11_16.2 (%U) = binding_pattern n
-// CHECK:STDOUT:     }
-// CHECK:STDOUT:     %p.ref: ref @F.%ptr.loc12_11.2 (%ptr) = name_ref p, %p
-// CHECK:STDOUT:     %.loc17_15: @F.%ptr.loc12_11.2 (%ptr) = bind_value %p.ref
-// CHECK:STDOUT:     %.loc17_14.1: ref @F.%T.loc11_6.2 (%T) = deref %.loc17_15
-// CHECK:STDOUT:     %U.ref: type = name_ref U, %U.loc11_16.1 [symbolic = %U.loc11_16.2 (constants.%U)]
-// CHECK:STDOUT:     %.loc17_14.2: @F.%U.loc11_16.2 (%U) = converted %.loc17_14.1, <error> [concrete = <error>]
-// CHECK:STDOUT:     %n: @F.%U.loc11_16.2 (%U) = bind_name n, <error>
-// CHECK:STDOUT:     return
-// CHECK:STDOUT:   }
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: specific @F(constants.%T, constants.%U) {
-// CHECK:STDOUT:   %T.loc11_6.2 => constants.%T
-// CHECK:STDOUT:   %T.patt.loc11_6.2 => constants.%T.patt
-// CHECK:STDOUT:   %U.loc11_16.2 => constants.%U
-// CHECK:STDOUT:   %U.patt.loc11_16.2 => constants.%U.patt
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/function/generic/no_prelude/type_param.carbon b/toolchain/check/testdata/function/generic/no_prelude/type_param.carbon
deleted file mode 100644
index f4a81654d929..000000000000
--- a/toolchain/check/testdata/function/generic/no_prelude/type_param.carbon
+++ /dev/null
@@ -1,76 +0,0 @@
-// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
-// Exceptions. See /LICENSE for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-// AUTOUPDATE
-// TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/function/generic/no_prelude/type_param.carbon
-// TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/function/generic/no_prelude/type_param.carbon
-
-fn F(T:! type) {
-  var p: T*;
-  let n: T = *p;
-}
-
-// CHECK:STDOUT: --- type_param.carbon
-// CHECK:STDOUT:
-// CHECK:STDOUT: constants {
-// CHECK:STDOUT:   %T: type = bind_symbolic_name T, 0 [symbolic]
-// CHECK:STDOUT:   %T.patt: type = symbolic_binding_pattern T, 0 [symbolic]
-// CHECK:STDOUT:   %F.type: type = fn_type @F [concrete]
-// CHECK:STDOUT:   %F: %F.type = struct_value () [concrete]
-// CHECK:STDOUT:   %ptr: type = ptr_type %T [symbolic]
-// CHECK:STDOUT:   %require_complete.6e5: <witness> = require_complete_type %ptr [symbolic]
-// CHECK:STDOUT:   %require_complete.4ae: <witness> = require_complete_type %T [symbolic]
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: file {
-// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
-// CHECK:STDOUT:     .F = %F.decl
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {
-// CHECK:STDOUT:     %T.patt.loc11_6.1: type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc11_6.2 (constants.%T.patt)]
-// CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %T.loc11_6.1: type = bind_symbolic_name T, 0 [symbolic = %T.loc11_6.2 (constants.%T)]
-// CHECK:STDOUT:   }
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: generic fn @F(%T.loc11_6.1: type) {
-// CHECK:STDOUT:   %T.loc11_6.2: type = bind_symbolic_name T, 0 [symbolic = %T.loc11_6.2 (constants.%T)]
-// CHECK:STDOUT:   %T.patt.loc11_6.2: type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc11_6.2 (constants.%T.patt)]
-// CHECK:STDOUT:
-// CHECK:STDOUT: !definition:
-// CHECK:STDOUT:   %ptr.loc12_11.2: type = ptr_type %T.loc11_6.2 [symbolic = %ptr.loc12_11.2 (constants.%ptr)]
-// CHECK:STDOUT:   %require_complete.loc12: <witness> = require_complete_type %ptr.loc12_11.2 [symbolic = %require_complete.loc12 (constants.%require_complete.6e5)]
-// CHECK:STDOUT:   %require_complete.loc13: <witness> = require_complete_type %T.loc11_6.2 [symbolic = %require_complete.loc13 (constants.%require_complete.4ae)]
-// CHECK:STDOUT:
-// CHECK:STDOUT:   fn() {
-// CHECK:STDOUT:   !entry:
-// CHECK:STDOUT:     name_binding_decl {
-// CHECK:STDOUT:       %p.patt: @F.%ptr.loc12_11.2 (%ptr) = binding_pattern p
-// CHECK:STDOUT:       %.loc12_3: @F.%ptr.loc12_11.2 (%ptr) = var_pattern %p.patt
-// CHECK:STDOUT:     }
-// CHECK:STDOUT:     %p.var: ref @F.%ptr.loc12_11.2 (%ptr) = var p
-// CHECK:STDOUT:     %.loc12_11: type = splice_block %ptr.loc12_11.1 [symbolic = %ptr.loc12_11.2 (constants.%ptr)] {
-// CHECK:STDOUT:       %T.ref.loc12: type = name_ref T, %T.loc11_6.1 [symbolic = %T.loc11_6.2 (constants.%T)]
-// CHECK:STDOUT:       %ptr.loc12_11.1: type = ptr_type %T.ref.loc12 [symbolic = %ptr.loc12_11.2 (constants.%ptr)]
-// CHECK:STDOUT:     }
-// CHECK:STDOUT:     %p: ref @F.%ptr.loc12_11.2 (%ptr) = bind_name p, %p.var
-// CHECK:STDOUT:     name_binding_decl {
-// CHECK:STDOUT:       %n.patt: @F.%T.loc11_6.2 (%T) = binding_pattern n
-// CHECK:STDOUT:     }
-// CHECK:STDOUT:     %p.ref: ref @F.%ptr.loc12_11.2 (%ptr) = name_ref p, %p
-// CHECK:STDOUT:     %.loc13_15: @F.%ptr.loc12_11.2 (%ptr) = bind_value %p.ref
-// CHECK:STDOUT:     %.loc13_14: ref @F.%T.loc11_6.2 (%T) = deref %.loc13_15
-// CHECK:STDOUT:     %T.ref.loc13: type = name_ref T, %T.loc11_6.1 [symbolic = %T.loc11_6.2 (constants.%T)]
-// CHECK:STDOUT:     %n: ref @F.%T.loc11_6.2 (%T) = bind_name n, %.loc13_14
-// CHECK:STDOUT:     return
-// CHECK:STDOUT:   }
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: specific @F(constants.%T) {
-// CHECK:STDOUT:   %T.loc11_6.2 => constants.%T
-// CHECK:STDOUT:   %T.patt.loc11_6.2 => constants.%T.patt
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/impl/lookup/no_prelude/impl_forall.carbon b/toolchain/check/testdata/impl/lookup/min_prelude/impl_forall.carbon
similarity index 98%
rename from toolchain/check/testdata/impl/lookup/no_prelude/impl_forall.carbon
rename to toolchain/check/testdata/impl/lookup/min_prelude/impl_forall.carbon
index b0d3b0616acd..ffc453ad7796 100644
--- a/toolchain/check/testdata/impl/lookup/no_prelude/impl_forall.carbon
+++ b/toolchain/check/testdata/impl/lookup/min_prelude/impl_forall.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/impl/lookup/no_prelude/impl_forall.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/impl/lookup/min_prelude/impl_forall.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/impl/lookup/no_prelude/impl_forall.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/impl/lookup/min_prelude/impl_forall.carbon
 
 // --- impl_forall.carbon
 library "[[@TEST_NAME]]";
@@ -124,13 +127,21 @@ fn TestSpecific(a: A({})) -> {} {
 // CHECK:STDOUT:   %empty_struct: %empty_struct_type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .A = %A.decl
 // CHECK:STDOUT:     .I = %I.decl
 // CHECK:STDOUT:     .TestGeneric = %TestGeneric.decl
 // CHECK:STDOUT:     .TestSpecific = %TestSpecific.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %A.decl: %A.type = class_decl @A [concrete = constants.%A.generic] {
 // CHECK:STDOUT:     %T.patt.loc3_9.1: type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc3_9.2 (constants.%T.patt)]
 // CHECK:STDOUT:   } {
@@ -568,3 +579,9 @@ fn TestSpecific(a: A({})) -> {} {
 // CHECK:STDOUT:   %A.elem => constants.%A.elem.2af
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/impl/lookup/no_prelude/import.carbon b/toolchain/check/testdata/impl/lookup/min_prelude/import.carbon
similarity index 95%
rename from toolchain/check/testdata/impl/lookup/no_prelude/import.carbon
rename to toolchain/check/testdata/impl/lookup/min_prelude/import.carbon
index dc1d4391d420..484f690df068 100644
--- a/toolchain/check/testdata/impl/lookup/no_prelude/import.carbon
+++ b/toolchain/check/testdata/impl/lookup/min_prelude/import.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/impl/lookup/no_prelude/import.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/impl/lookup/min_prelude/import.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/impl/lookup/no_prelude/import.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/impl/lookup/min_prelude/import.carbon
 
 // --- package_a.carbon
 
@@ -238,11 +241,19 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:   %HasF.facet: %HasF.type = facet_value %C, (%HasF.impl_witness) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .HasF = %HasF.decl
 // CHECK:STDOUT:     .C = %C.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %HasF.decl: type = interface_decl @HasF [concrete = constants.%HasF.type] {} {}
 // CHECK:STDOUT:   %C.decl: type = class_decl @C [concrete = constants.%C] {} {}
 // CHECK:STDOUT:   impl_decl @impl [concrete] {} {
@@ -355,6 +366,9 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
 // CHECK:STDOUT:   %PackageA: <namespace> = namespace file.%PackageA.import, [concrete] {
 // CHECK:STDOUT:     .C = %PackageA.C
 // CHECK:STDOUT:     .HasF = %PackageA.HasF
@@ -362,20 +376,22 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %PackageA.C: type = import_ref PackageA//default, C, loaded [concrete = constants.%C]
 // CHECK:STDOUT:   %PackageA.import_ref.8f2: <witness> = import_ref PackageA//default, loc8_10, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %PackageA.import_ref.2c4 = import_ref PackageA//default, inst38 [no loc], unloaded
+// CHECK:STDOUT:   %PackageA.import_ref.2c4 = import_ref PackageA//default, inst40 [no loc], unloaded
 // CHECK:STDOUT:   %PackageA.HasF: type = import_ref PackageA//default, HasF, loaded [concrete = constants.%HasF.type]
-// CHECK:STDOUT:   %PackageA.import_ref.28c = import_ref PackageA//default, inst17 [no loc], unloaded
+// CHECK:STDOUT:   %PackageA.import_ref.28c = import_ref PackageA//default, inst19 [no loc], unloaded
 // CHECK:STDOUT:   %PackageA.import_ref.c63 = import_ref PackageA//default, loc5_21, unloaded
 // CHECK:STDOUT:   %PackageA.F: %F.type.dbc = import_ref PackageA//default, F, loaded [concrete = constants.%F.a2b]
-// CHECK:STDOUT:   %PackageA.import_ref.e73: %HasF.type = import_ref PackageA//default, inst17 [no loc], loaded [symbolic = constants.%Self.cf3]
+// CHECK:STDOUT:   %PackageA.import_ref.e73: %HasF.type = import_ref PackageA//default, inst19 [no loc], loaded [symbolic = constants.%Self.cf3]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .PackageA = imports.%PackageA
 // CHECK:STDOUT:     .HasG = %HasG.decl
 // CHECK:STDOUT:     .D = %D.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %PackageA.import = import PackageA
 // CHECK:STDOUT:   %HasG.decl: type = interface_decl @HasG [concrete = constants.%HasG.type] {} {}
 // CHECK:STDOUT:   %D.decl: type = class_decl @D [concrete = constants.%D] {} {}
@@ -569,6 +585,9 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
 // CHECK:STDOUT:   %PackageA: <namespace> = namespace file.%PackageA.import, [concrete] {
 // CHECK:STDOUT:     .C = %PackageA.C
 // CHECK:STDOUT:     .HasF = %PackageA.HasF
@@ -576,12 +595,12 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %PackageA.C: type = import_ref PackageA//default, C, loaded [concrete = constants.%C]
 // CHECK:STDOUT:   %PackageA.import_ref.8f2: <witness> = import_ref PackageA//default, loc8_10, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %PackageA.import_ref.2c4 = import_ref PackageA//default, inst38 [no loc], unloaded
+// CHECK:STDOUT:   %PackageA.import_ref.2c4 = import_ref PackageA//default, inst40 [no loc], unloaded
 // CHECK:STDOUT:   %PackageA.HasF: type = import_ref PackageA//default, HasF, loaded [concrete = constants.%HasF.type]
-// CHECK:STDOUT:   %PackageA.import_ref.28c = import_ref PackageA//default, inst17 [no loc], unloaded
+// CHECK:STDOUT:   %PackageA.import_ref.28c = import_ref PackageA//default, inst19 [no loc], unloaded
 // CHECK:STDOUT:   %PackageA.import_ref.b36: %HasF.assoc_type = import_ref PackageA//default, loc5_21, loaded [concrete = constants.%assoc0]
 // CHECK:STDOUT:   %PackageA.F = import_ref PackageA//default, F, unloaded
-// CHECK:STDOUT:   %PackageA.import_ref.e73: %HasF.type = import_ref PackageA//default, inst17 [no loc], loaded [symbolic = constants.%Self]
+// CHECK:STDOUT:   %PackageA.import_ref.e73: %HasF.type = import_ref PackageA//default, inst19 [no loc], loaded [symbolic = constants.%Self]
 // CHECK:STDOUT:   %PackageA.import_ref.c12: <witness> = import_ref PackageA//default, loc11_16, loaded [concrete = constants.%HasF.impl_witness]
 // CHECK:STDOUT:   %PackageA.import_ref.29a: type = import_ref PackageA//default, loc11_6, loaded [concrete = constants.%C]
 // CHECK:STDOUT:   %PackageA.import_ref.e8c: type = import_ref PackageA//default, loc11_11, loaded [concrete = constants.%HasF.type]
@@ -589,9 +608,11 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .PackageA = imports.%PackageA
 // CHECK:STDOUT:     .TestCF = %TestCF.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %PackageA.import = import PackageA
 // CHECK:STDOUT:   %TestCF.decl: %TestCF.type = fn_decl @TestCF [concrete = constants.%TestCF] {
 // CHECK:STDOUT:     %c.patt: %C = binding_pattern c
@@ -677,6 +698,9 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
 // CHECK:STDOUT:   %PackageA: <namespace> = namespace file.%PackageA.import, [concrete] {
 // CHECK:STDOUT:     .HasF = %PackageA.HasF
 // CHECK:STDOUT:     import PackageA//default
@@ -687,18 +711,18 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %PackageB.D: type = import_ref PackageB//default, D, loaded [concrete = constants.%D]
 // CHECK:STDOUT:   %PackageB.import_ref.8f2: <witness> = import_ref PackageB//default, loc10_10, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %PackageB.import_ref.cab = import_ref PackageB//default, inst40 [no loc], unloaded
+// CHECK:STDOUT:   %PackageB.import_ref.cab = import_ref PackageB//default, inst42 [no loc], unloaded
 // CHECK:STDOUT:   %PackageA.HasF: type = import_ref PackageA//default, HasF, loaded [concrete = constants.%HasF.type]
-// CHECK:STDOUT:   %PackageA.import_ref.28c = import_ref PackageA//default, inst17 [no loc], unloaded
+// CHECK:STDOUT:   %PackageA.import_ref.28c = import_ref PackageA//default, inst19 [no loc], unloaded
 // CHECK:STDOUT:   %PackageA.import_ref.b36: %HasF.assoc_type = import_ref PackageA//default, loc5_21, loaded [concrete = constants.%assoc0]
 // CHECK:STDOUT:   %PackageA.F = import_ref PackageA//default, F, unloaded
-// CHECK:STDOUT:   %PackageA.import_ref.e73: %HasF.type = import_ref PackageA//default, inst17 [no loc], loaded [symbolic = constants.%Self.cf3]
+// CHECK:STDOUT:   %PackageA.import_ref.e73: %HasF.type = import_ref PackageA//default, inst19 [no loc], loaded [symbolic = constants.%Self.cf3]
 // CHECK:STDOUT:   %PackageA.import_ref.5cd = import_ref PackageA//default, loc11_16, unloaded
 // CHECK:STDOUT:   %PackageA.import_ref.8f2: <witness> = import_ref PackageA//default, loc8_10, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %PackageA.import_ref.2c4 = import_ref PackageA//default, inst38 [no loc], unloaded
+// CHECK:STDOUT:   %PackageA.import_ref.2c4 = import_ref PackageA//default, inst40 [no loc], unloaded
 // CHECK:STDOUT:   %PackageA.import_ref.29a: type = import_ref PackageA//default, loc11_6, loaded [concrete = constants.%C]
 // CHECK:STDOUT:   %PackageA.import_ref.e8c: type = import_ref PackageA//default, loc11_11, loaded [concrete = constants.%HasF.type]
-// CHECK:STDOUT:   %PackageB.import_ref.5d8 = import_ref PackageB//default, inst19 [no loc], unloaded
+// CHECK:STDOUT:   %PackageB.import_ref.5d8 = import_ref PackageB//default, inst21 [no loc], unloaded
 // CHECK:STDOUT:   %PackageB.import_ref.910 = import_ref PackageB//default, loc7_21, unloaded
 // CHECK:STDOUT:   %PackageB.G = import_ref PackageB//default, G, unloaded
 // CHECK:STDOUT:   %PackageB.import_ref.ea7 = import_ref PackageB//default, loc13_25, unloaded
@@ -714,10 +738,12 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .PackageA = imports.%PackageA
 // CHECK:STDOUT:     .PackageB = imports.%PackageB
 // CHECK:STDOUT:     .TestDF = %TestDF.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %PackageA.import = import PackageA
 // CHECK:STDOUT:   %PackageB.import = import PackageB
 // CHECK:STDOUT:   %TestDF.decl: %TestDF.type = fn_decl @TestDF [concrete = constants.%TestDF] {
@@ -833,6 +859,9 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
 // CHECK:STDOUT:   %PackageA: <namespace> = namespace file.%PackageA.import, [concrete] {
 // CHECK:STDOUT:     .C = %PackageA.C
 // CHECK:STDOUT:     import PackageA//default
@@ -843,13 +872,13 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %PackageA.C: type = import_ref PackageA//default, C, loaded [concrete = constants.%C]
 // CHECK:STDOUT:   %PackageA.import_ref.8f2: <witness> = import_ref PackageA//default, loc8_10, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %PackageA.import_ref.2c4 = import_ref PackageA//default, inst38 [no loc], unloaded
+// CHECK:STDOUT:   %PackageA.import_ref.2c4 = import_ref PackageA//default, inst40 [no loc], unloaded
 // CHECK:STDOUT:   %PackageB.HasG: type = import_ref PackageB//default, HasG, loaded [concrete = constants.%HasG.type]
-// CHECK:STDOUT:   %PackageB.import_ref.5d8 = import_ref PackageB//default, inst19 [no loc], unloaded
+// CHECK:STDOUT:   %PackageB.import_ref.5d8 = import_ref PackageB//default, inst21 [no loc], unloaded
 // CHECK:STDOUT:   %PackageB.import_ref.6c2: %HasG.assoc_type = import_ref PackageB//default, loc7_21, loaded [concrete = constants.%assoc0]
 // CHECK:STDOUT:   %PackageB.G = import_ref PackageB//default, G, unloaded
-// CHECK:STDOUT:   %PackageB.import_ref.ef5: %HasG.type = import_ref PackageB//default, inst19 [no loc], loaded [symbolic = constants.%Self.fcb]
-// CHECK:STDOUT:   %PackageA.import_ref.28c = import_ref PackageA//default, inst17 [no loc], unloaded
+// CHECK:STDOUT:   %PackageB.import_ref.ef5: %HasG.type = import_ref PackageB//default, inst21 [no loc], loaded [symbolic = constants.%Self.fcb]
+// CHECK:STDOUT:   %PackageA.import_ref.28c = import_ref PackageA//default, inst19 [no loc], unloaded
 // CHECK:STDOUT:   %PackageA.import_ref.c63 = import_ref PackageA//default, loc5_21, unloaded
 // CHECK:STDOUT:   %PackageA.F = import_ref PackageA//default, F, unloaded
 // CHECK:STDOUT:   %PackageA.import_ref.5cd = import_ref PackageA//default, loc11_16, unloaded
@@ -860,7 +889,7 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:   %PackageB.import_ref.cee586.1: type = import_ref PackageB//default, loc13_20, loaded [concrete = constants.%HasG.type]
 // CHECK:STDOUT:   %PackageB.import_ref.5ba = import_ref PackageB//default, loc18_25, unloaded
 // CHECK:STDOUT:   %PackageB.import_ref.8f2: <witness> = import_ref PackageB//default, loc10_10, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %PackageB.import_ref.cab = import_ref PackageB//default, inst40 [no loc], unloaded
+// CHECK:STDOUT:   %PackageB.import_ref.cab = import_ref PackageB//default, inst42 [no loc], unloaded
 // CHECK:STDOUT:   %PackageB.import_ref.aa9f8a.1: type = import_ref PackageB//default, loc18_6, loaded [concrete = constants.%D]
 // CHECK:STDOUT:   %PackageB.import_ref.831: type = import_ref PackageB//default, loc18_19, loaded [concrete = constants.%HasF.type]
 // CHECK:STDOUT:   %PackageB.import_ref.569 = import_ref PackageB//default, loc23_16, unloaded
@@ -870,10 +899,12 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .PackageA = imports.%PackageA
 // CHECK:STDOUT:     .PackageB = imports.%PackageB
 // CHECK:STDOUT:     .TestCG = %TestCG.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %PackageA.import = import PackageA
 // CHECK:STDOUT:   %PackageB.import = import PackageB
 // CHECK:STDOUT:   %TestCG.decl: %TestCG.type = fn_decl @TestCG [concrete = constants.%TestCG] {
@@ -989,6 +1020,9 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
 // CHECK:STDOUT:   %PackageB: <namespace> = namespace file.%PackageB.import, [concrete] {
 // CHECK:STDOUT:     .D = %PackageB.D
 // CHECK:STDOUT:     .HasG = %PackageB.HasG
@@ -996,19 +1030,19 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %PackageB.D: type = import_ref PackageB//default, D, loaded [concrete = constants.%D]
 // CHECK:STDOUT:   %PackageB.import_ref.8f2: <witness> = import_ref PackageB//default, loc10_10, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %PackageB.import_ref.cab = import_ref PackageB//default, inst40 [no loc], unloaded
+// CHECK:STDOUT:   %PackageB.import_ref.cab = import_ref PackageB//default, inst42 [no loc], unloaded
 // CHECK:STDOUT:   %PackageB.HasG: type = import_ref PackageB//default, HasG, loaded [concrete = constants.%HasG.type]
-// CHECK:STDOUT:   %PackageB.import_ref.5d8 = import_ref PackageB//default, inst19 [no loc], unloaded
+// CHECK:STDOUT:   %PackageB.import_ref.5d8 = import_ref PackageB//default, inst21 [no loc], unloaded
 // CHECK:STDOUT:   %PackageB.import_ref.6c2: %HasG.assoc_type = import_ref PackageB//default, loc7_21, loaded [concrete = constants.%assoc0]
 // CHECK:STDOUT:   %PackageB.G = import_ref PackageB//default, G, unloaded
-// CHECK:STDOUT:   %PackageB.import_ref.ef5: %HasG.type = import_ref PackageB//default, inst19 [no loc], loaded [symbolic = constants.%Self.fcb]
+// CHECK:STDOUT:   %PackageB.import_ref.ef5: %HasG.type = import_ref PackageB//default, inst21 [no loc], loaded [symbolic = constants.%Self.fcb]
 // CHECK:STDOUT:   %PackageB.import_ref.ea7 = import_ref PackageB//default, loc13_25, unloaded
-// CHECK:STDOUT:   %PackageB.import_ref.8db: <witness> = import_ref PackageB//default, inst49 [indirect], loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %PackageB.import_ref.6a9 = import_ref PackageB//default, inst50 [indirect], unloaded
+// CHECK:STDOUT:   %PackageB.import_ref.8db: <witness> = import_ref PackageB//default, inst51 [indirect], loaded [concrete = constants.%complete_type]
+// CHECK:STDOUT:   %PackageB.import_ref.6a9 = import_ref PackageB//default, inst52 [indirect], unloaded
 // CHECK:STDOUT:   %PackageB.import_ref.dfb: type = import_ref PackageB//default, loc13_14, loaded [concrete = constants.%C]
 // CHECK:STDOUT:   %PackageB.import_ref.cee586.1: type = import_ref PackageB//default, loc13_20, loaded [concrete = constants.%HasG.type]
-// CHECK:STDOUT:   %PackageB.import_ref.96f = import_ref PackageB//default, inst74 [indirect], unloaded
-// CHECK:STDOUT:   %PackageB.import_ref.a0b = import_ref PackageB//default, inst75 [indirect], unloaded
+// CHECK:STDOUT:   %PackageB.import_ref.96f = import_ref PackageB//default, inst76 [indirect], unloaded
+// CHECK:STDOUT:   %PackageB.import_ref.a0b = import_ref PackageB//default, inst77 [indirect], unloaded
 // CHECK:STDOUT:   %PackageB.F = import_ref PackageB//default, F, unloaded
 // CHECK:STDOUT:   %PackageB.import_ref.5ba = import_ref PackageB//default, loc18_25, unloaded
 // CHECK:STDOUT:   %PackageB.import_ref.aa9f8a.1: type = import_ref PackageB//default, loc18_6, loaded [concrete = constants.%D]
@@ -1020,9 +1054,11 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .PackageB = imports.%PackageB
 // CHECK:STDOUT:     .TestDG = %TestDG.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %PackageB.import = import PackageB
 // CHECK:STDOUT:   %TestDG.decl: %TestDG.type = fn_decl @TestDG [concrete = constants.%TestDG] {
 // CHECK:STDOUT:     %d.patt: %D = binding_pattern d
@@ -1123,10 +1159,18 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:   %Z.facet: %Z.type = facet_value %empty_tuple.type, (%Z.impl_witness) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Z = %Z.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Z.decl: type = interface_decl @Z [concrete = constants.%Z.type] {} {}
 // CHECK:STDOUT:   impl_decl @impl [concrete] {} {
 // CHECK:STDOUT:     %.loc8_7.1: %empty_tuple.type = tuple_literal ()
@@ -1218,15 +1262,18 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
 // CHECK:STDOUT:   %PackageAssociatedInterface: <namespace> = namespace file.%PackageAssociatedInterface.import, [concrete] {
 // CHECK:STDOUT:     .Z = %PackageAssociatedInterface.Z
 // CHECK:STDOUT:     import PackageAssociatedInterface//default
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %PackageAssociatedInterface.Z: type = import_ref PackageAssociatedInterface//default, Z, loaded [concrete = constants.%Z.type]
-// CHECK:STDOUT:   %PackageAssociatedInterface.import_ref.f88 = import_ref PackageAssociatedInterface//default, inst17 [no loc], unloaded
+// CHECK:STDOUT:   %PackageAssociatedInterface.import_ref.f88 = import_ref PackageAssociatedInterface//default, inst19 [no loc], unloaded
 // CHECK:STDOUT:   %PackageAssociatedInterface.import_ref.609: %Z.assoc_type = import_ref PackageAssociatedInterface//default, loc5_21, loaded [concrete = constants.%assoc0]
 // CHECK:STDOUT:   %PackageAssociatedInterface.H = import_ref PackageAssociatedInterface//default, H, unloaded
-// CHECK:STDOUT:   %PackageAssociatedInterface.import_ref.d26: %Z.type = import_ref PackageAssociatedInterface//default, inst17 [no loc], loaded [symbolic = constants.%Self]
+// CHECK:STDOUT:   %PackageAssociatedInterface.import_ref.d26: %Z.type = import_ref PackageAssociatedInterface//default, inst19 [no loc], loaded [symbolic = constants.%Self]
 // CHECK:STDOUT:   %PackageAssociatedInterface.import_ref.d8c: <witness> = import_ref PackageAssociatedInterface//default, loc8_14, loaded [concrete = constants.%Z.impl_witness]
 // CHECK:STDOUT:   %PackageAssociatedInterface.import_ref.e5c: type = import_ref PackageAssociatedInterface//default, loc8_7, loaded [concrete = constants.%empty_tuple.type]
 // CHECK:STDOUT:   %PackageAssociatedInterface.import_ref.df1: type = import_ref PackageAssociatedInterface//default, loc8_12, loaded [concrete = constants.%Z.type]
@@ -1234,9 +1281,11 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .PackageAssociatedInterface = imports.%PackageAssociatedInterface
 // CHECK:STDOUT:     .J = %J.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %PackageAssociatedInterface.import = import PackageAssociatedInterface
 // CHECK:STDOUT:   %J.decl: %J.type = fn_decl @J [concrete = constants.%J] {} {}
 // CHECK:STDOUT: }
@@ -1303,11 +1352,19 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type %Self.as_type [symbolic]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .AnyParam = %AnyParam.decl
 // CHECK:STDOUT:     .Y = %Y.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %AnyParam.decl: %AnyParam.type = class_decl @AnyParam [concrete = constants.%AnyParam.generic] {
 // CHECK:STDOUT:     %T.patt.loc4_16.1: type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc4_16.2 (constants.%T.patt)]
 // CHECK:STDOUT:     %X.patt.loc4_26.1: @AnyParam.%T.loc4_16.2 (%T) = symbolic_binding_pattern X, 1 [symbolic = %X.patt.loc4_26.2 (constants.%X.patt)]
@@ -1423,6 +1480,9 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
 // CHECK:STDOUT:   %PackageHasParam: <namespace> = namespace file.%PackageHasParam.import, [concrete] {
 // CHECK:STDOUT:     .AnyParam = %PackageHasParam.AnyParam
 // CHECK:STDOUT:     .Y = %PackageHasParam.Y
@@ -1432,20 +1492,22 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:   %PackageHasParam.import_ref.5ab: type = import_ref PackageHasParam//default, loc4_16, loaded [symbolic = @AnyParam.%T (constants.%T)]
 // CHECK:STDOUT:   %PackageHasParam.import_ref.34c: @AnyParam.%T (%T) = import_ref PackageHasParam//default, loc4_26, loaded [symbolic = @AnyParam.%X (constants.%X)]
 // CHECK:STDOUT:   %PackageHasParam.import_ref.8f2: <witness> = import_ref PackageHasParam//default, loc4_34, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %PackageHasParam.import_ref.601 = import_ref PackageHasParam//default, inst32 [no loc], unloaded
+// CHECK:STDOUT:   %PackageHasParam.import_ref.601 = import_ref PackageHasParam//default, inst34 [no loc], unloaded
 // CHECK:STDOUT:   %PackageHasParam.Y: type = import_ref PackageHasParam//default, Y, loaded [concrete = constants.%Y.type]
-// CHECK:STDOUT:   %PackageHasParam.import_ref.dc1 = import_ref PackageHasParam//default, inst39 [no loc], unloaded
+// CHECK:STDOUT:   %PackageHasParam.import_ref.dc1 = import_ref PackageHasParam//default, inst41 [no loc], unloaded
 // CHECK:STDOUT:   %PackageHasParam.import_ref.f69: %Y.assoc_type = import_ref PackageHasParam//default, loc7_22, loaded [concrete = constants.%assoc0]
 // CHECK:STDOUT:   %PackageHasParam.K: %K.type.311 = import_ref PackageHasParam//default, K, loaded [concrete = constants.%K.7a1]
-// CHECK:STDOUT:   %PackageHasParam.import_ref.292: %Y.type = import_ref PackageHasParam//default, inst39 [no loc], loaded [symbolic = constants.%Self.f64]
+// CHECK:STDOUT:   %PackageHasParam.import_ref.292: %Y.type = import_ref PackageHasParam//default, inst41 [no loc], loaded [symbolic = constants.%Self.f64]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .PackageHasParam = imports.%PackageHasParam
 // CHECK:STDOUT:     .GenericInterface = %GenericInterface.decl
 // CHECK:STDOUT:     .L = %L.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %PackageHasParam.import = import PackageHasParam
 // CHECK:STDOUT:   %GenericInterface.decl: %GenericInterface.type.c92 = interface_decl @GenericInterface [concrete = constants.%GenericInterface.generic] {
 // CHECK:STDOUT:     %U.patt.loc6_28.1: type = symbolic_binding_pattern U, 0 [symbolic = %U.patt.loc6_28.2 (constants.%U.patt)]
@@ -1636,6 +1698,9 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
 // CHECK:STDOUT:   %PackageHasParam: <namespace> = namespace file.%PackageHasParam.import, [concrete] {
 // CHECK:STDOUT:     .AnyParam = %PackageHasParam.AnyParam
 // CHECK:STDOUT:     .Y = %PackageHasParam.Y
@@ -1649,15 +1714,15 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:   %PackageHasParam.import_ref.5ab: type = import_ref PackageHasParam//default, loc4_16, loaded [symbolic = @AnyParam.%T (constants.%T)]
 // CHECK:STDOUT:   %PackageHasParam.import_ref.34c: @AnyParam.%T (%T) = import_ref PackageHasParam//default, loc4_26, loaded [symbolic = @AnyParam.%X (constants.%X)]
 // CHECK:STDOUT:   %PackageHasParam.import_ref.8f2: <witness> = import_ref PackageHasParam//default, loc4_34, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %PackageHasParam.import_ref.601 = import_ref PackageHasParam//default, inst32 [no loc], unloaded
+// CHECK:STDOUT:   %PackageHasParam.import_ref.601 = import_ref PackageHasParam//default, inst34 [no loc], unloaded
 // CHECK:STDOUT:   %PackageGenericInterface.GenericInterface: %GenericInterface.type.0da = import_ref PackageGenericInterface//default, GenericInterface, loaded [concrete = constants.%GenericInterface.generic]
 // CHECK:STDOUT:   %PackageGenericInterface.import_ref.5ab: type = import_ref PackageGenericInterface//default, loc6_28, loaded [symbolic = @GenericInterface.%U (constants.%U)]
-// CHECK:STDOUT:   %PackageGenericInterface.import_ref.c3b = import_ref PackageGenericInterface//default, inst28 [no loc], unloaded
+// CHECK:STDOUT:   %PackageGenericInterface.import_ref.c3b = import_ref PackageGenericInterface//default, inst30 [no loc], unloaded
 // CHECK:STDOUT:   %PackageHasParam.Y: type = import_ref PackageHasParam//default, Y, loaded [concrete = constants.%Y.type]
-// CHECK:STDOUT:   %PackageHasParam.import_ref.dc1 = import_ref PackageHasParam//default, inst39 [no loc], unloaded
+// CHECK:STDOUT:   %PackageHasParam.import_ref.dc1 = import_ref PackageHasParam//default, inst41 [no loc], unloaded
 // CHECK:STDOUT:   %PackageHasParam.import_ref.f69: %Y.assoc_type = import_ref PackageHasParam//default, loc7_22, loaded [concrete = constants.%assoc0]
 // CHECK:STDOUT:   %PackageHasParam.K = import_ref PackageHasParam//default, K, unloaded
-// CHECK:STDOUT:   %PackageHasParam.import_ref.292: %Y.type = import_ref PackageHasParam//default, inst39 [no loc], loaded [symbolic = constants.%Self.f64]
+// CHECK:STDOUT:   %PackageHasParam.import_ref.292: %Y.type = import_ref PackageHasParam//default, inst41 [no loc], loaded [symbolic = constants.%Self.f64]
 // CHECK:STDOUT:   %PackageGenericInterface.import_ref.53c: <witness> = import_ref PackageGenericInterface//default, loc8_70, loaded [concrete = constants.%Y.impl_witness]
 // CHECK:STDOUT:   %PackageGenericInterface.import_ref.321: type = import_ref PackageGenericInterface//default, loc8_47, loaded [concrete = constants.%AnyParam.861]
 // CHECK:STDOUT:   %PackageGenericInterface.import_ref.ca6: type = import_ref PackageGenericInterface//default, loc8_67, loaded [concrete = constants.%Y.type]
@@ -1665,10 +1730,12 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .PackageHasParam = imports.%PackageHasParam
 // CHECK:STDOUT:     .PackageGenericInterface = imports.%PackageGenericInterface
 // CHECK:STDOUT:     .M = %M.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %PackageHasParam.import = import PackageHasParam
 // CHECK:STDOUT:   %PackageGenericInterface.import = import PackageGenericInterface
 // CHECK:STDOUT:   %M.decl: %M.type = fn_decl @M [concrete = constants.%M] {} {}
@@ -1825,6 +1892,9 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
 // CHECK:STDOUT:   %PackageHasParam: <namespace> = namespace file.%PackageHasParam.import, [concrete] {
 // CHECK:STDOUT:     .AnyParam = %PackageHasParam.AnyParam
 // CHECK:STDOUT:     .Y = %PackageHasParam.Y
@@ -1834,20 +1904,22 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:   %PackageHasParam.import_ref.5ab: type = import_ref PackageHasParam//default, loc4_16, loaded [symbolic = @AnyParam.%T (constants.%T)]
 // CHECK:STDOUT:   %PackageHasParam.import_ref.34c: @AnyParam.%T (%T) = import_ref PackageHasParam//default, loc4_26, loaded [symbolic = @AnyParam.%X (constants.%X)]
 // CHECK:STDOUT:   %PackageHasParam.import_ref.8f2: <witness> = import_ref PackageHasParam//default, loc4_34, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %PackageHasParam.import_ref.601 = import_ref PackageHasParam//default, inst32 [no loc], unloaded
+// CHECK:STDOUT:   %PackageHasParam.import_ref.601 = import_ref PackageHasParam//default, inst34 [no loc], unloaded
 // CHECK:STDOUT:   %PackageHasParam.Y: type = import_ref PackageHasParam//default, Y, loaded [concrete = constants.%Y.type]
-// CHECK:STDOUT:   %PackageHasParam.import_ref.dc1 = import_ref PackageHasParam//default, inst39 [no loc], unloaded
+// CHECK:STDOUT:   %PackageHasParam.import_ref.dc1 = import_ref PackageHasParam//default, inst41 [no loc], unloaded
 // CHECK:STDOUT:   %PackageHasParam.import_ref.f69: %Y.assoc_type = import_ref PackageHasParam//default, loc7_22, loaded [concrete = constants.%assoc0]
 // CHECK:STDOUT:   %PackageHasParam.K: %K.type.311 = import_ref PackageHasParam//default, K, loaded [concrete = constants.%K.7a1]
-// CHECK:STDOUT:   %PackageHasParam.import_ref.292: %Y.type = import_ref PackageHasParam//default, inst39 [no loc], loaded [symbolic = constants.%Self]
+// CHECK:STDOUT:   %PackageHasParam.import_ref.292: %Y.type = import_ref PackageHasParam//default, inst41 [no loc], loaded [symbolic = constants.%Self]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .PackageHasParam = imports.%PackageHasParam
 // CHECK:STDOUT:     .GenericClass = %GenericClass.decl
 // CHECK:STDOUT:     .L = %L.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %PackageHasParam.import = import PackageHasParam
 // CHECK:STDOUT:   %GenericClass.decl: %GenericClass.type = class_decl @GenericClass [concrete = constants.%GenericClass.generic] {
 // CHECK:STDOUT:     %U.patt.loc6_20.1: type = symbolic_binding_pattern U, 0 [symbolic = %U.patt.loc6_20.2 (constants.%U.patt)]
@@ -2033,6 +2105,9 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
 // CHECK:STDOUT:   %PackageHasParam: <namespace> = namespace file.%PackageHasParam.import, [concrete] {
 // CHECK:STDOUT:     .AnyParam = %PackageHasParam.AnyParam
 // CHECK:STDOUT:     .Y = %PackageHasParam.Y
@@ -2046,16 +2121,16 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:   %PackageHasParam.import_ref.5ab: type = import_ref PackageHasParam//default, loc4_16, loaded [symbolic = @AnyParam.%T (constants.%T)]
 // CHECK:STDOUT:   %PackageHasParam.import_ref.34c: @AnyParam.%T (%T) = import_ref PackageHasParam//default, loc4_26, loaded [symbolic = @AnyParam.%X (constants.%X)]
 // CHECK:STDOUT:   %PackageHasParam.import_ref.8f2: <witness> = import_ref PackageHasParam//default, loc4_34, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %PackageHasParam.import_ref.601 = import_ref PackageHasParam//default, inst32 [no loc], unloaded
+// CHECK:STDOUT:   %PackageHasParam.import_ref.601 = import_ref PackageHasParam//default, inst34 [no loc], unloaded
 // CHECK:STDOUT:   %PackageGenericClass.GenericClass: %GenericClass.type = import_ref PackageGenericClass//default, GenericClass, loaded [concrete = constants.%GenericClass.generic]
 // CHECK:STDOUT:   %PackageGenericClass.import_ref.5ab: type = import_ref PackageGenericClass//default, loc6_20, loaded [symbolic = @GenericClass.%U (constants.%U)]
 // CHECK:STDOUT:   %PackageGenericClass.import_ref.8f2: <witness> = import_ref PackageGenericClass//default, loc6_31, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %PackageGenericClass.import_ref.065 = import_ref PackageGenericClass//default, inst27 [no loc], unloaded
+// CHECK:STDOUT:   %PackageGenericClass.import_ref.065 = import_ref PackageGenericClass//default, inst29 [no loc], unloaded
 // CHECK:STDOUT:   %PackageHasParam.Y: type = import_ref PackageHasParam//default, Y, loaded [concrete = constants.%Y.type]
-// CHECK:STDOUT:   %PackageHasParam.import_ref.dc1 = import_ref PackageHasParam//default, inst39 [no loc], unloaded
+// CHECK:STDOUT:   %PackageHasParam.import_ref.dc1 = import_ref PackageHasParam//default, inst41 [no loc], unloaded
 // CHECK:STDOUT:   %PackageHasParam.import_ref.f69: %Y.assoc_type = import_ref PackageHasParam//default, loc7_22, loaded [concrete = constants.%assoc0]
 // CHECK:STDOUT:   %PackageHasParam.K = import_ref PackageHasParam//default, K, unloaded
-// CHECK:STDOUT:   %PackageHasParam.import_ref.292: %Y.type = import_ref PackageHasParam//default, inst39 [no loc], loaded [symbolic = constants.%Self]
+// CHECK:STDOUT:   %PackageHasParam.import_ref.292: %Y.type = import_ref PackageHasParam//default, inst41 [no loc], loaded [symbolic = constants.%Self]
 // CHECK:STDOUT:   %PackageGenericClass.import_ref.246: <witness> = import_ref PackageGenericClass//default, loc8_66, loaded [concrete = constants.%Y.impl_witness]
 // CHECK:STDOUT:   %PackageGenericClass.import_ref.a0e: type = import_ref PackageGenericClass//default, loc8_43, loaded [concrete = constants.%AnyParam.d71]
 // CHECK:STDOUT:   %PackageGenericClass.import_ref.ca6: type = import_ref PackageGenericClass//default, loc8_63, loaded [concrete = constants.%Y.type]
@@ -2063,10 +2138,12 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .PackageHasParam = imports.%PackageHasParam
 // CHECK:STDOUT:     .PackageGenericClass = imports.%PackageGenericClass
 // CHECK:STDOUT:     .M = %M.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %PackageHasParam.import = import PackageHasParam
 // CHECK:STDOUT:   %PackageGenericClass.import = import PackageGenericClass
 // CHECK:STDOUT:   %M.decl: %M.type = fn_decl @M [concrete = constants.%M] {} {}
@@ -2224,8 +2301,15 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:   %I.facet: %I.type = facet_value %C.69b, (%I.impl_witness) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Extra1 = %Extra1.decl
 // CHECK:STDOUT:     .Extra2 = %Extra2.decl
 // CHECK:STDOUT:     .Extra3 = %Extra3.decl
@@ -2237,6 +2321,7 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:     .C = %C.decl
 // CHECK:STDOUT:     .I = %I.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Extra1.decl: type = interface_decl @Extra1 [concrete = constants.%Extra1.type] {} {}
 // CHECK:STDOUT:   %Extra2.decl: type = interface_decl @Extra2 [concrete = constants.%Extra2.type] {} {}
 // CHECK:STDOUT:   %Extra3.decl: type = interface_decl @Extra3 [concrete = constants.%Extra3.type] {} {}
@@ -2451,6 +2536,9 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
 // CHECK:STDOUT:   %HasExtraInterfaces: <namespace> = namespace file.%HasExtraInterfaces.import, [concrete] {
 // CHECK:STDOUT:     .C = %HasExtraInterfaces.C
 // CHECK:STDOUT:     .I = %HasExtraInterfaces.I
@@ -2459,30 +2547,32 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT:   %HasExtraInterfaces.C: %C.type = import_ref HasExtraInterfaces//default, C, loaded [concrete = constants.%C.generic]
 // CHECK:STDOUT:   %HasExtraInterfaces.import_ref.5ab: type = import_ref HasExtraInterfaces//default, loc13_9, loaded [symbolic = @C.%T (constants.%T)]
 // CHECK:STDOUT:   %HasExtraInterfaces.import_ref.8f2: <witness> = import_ref HasExtraInterfaces//default, loc13_20, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.4c0 = import_ref HasExtraInterfaces//default, inst57 [no loc], unloaded
+// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.4c0 = import_ref HasExtraInterfaces//default, inst59 [no loc], unloaded
 // CHECK:STDOUT:   %HasExtraInterfaces.I: type = import_ref HasExtraInterfaces//default, I, loaded [concrete = constants.%I.type]
-// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.e5d = import_ref HasExtraInterfaces//default, inst64 [no loc], unloaded
+// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.e5d = import_ref HasExtraInterfaces//default, inst66 [no loc], unloaded
 // CHECK:STDOUT:   %HasExtraInterfaces.import_ref.be9: %I.assoc_type = import_ref HasExtraInterfaces//default, loc14_33, loaded [concrete = constants.%assoc0]
 // CHECK:STDOUT:   %HasExtraInterfaces.F = import_ref HasExtraInterfaces//default, F, unloaded
-// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.1db: %I.type = import_ref HasExtraInterfaces//default, inst64 [no loc], loaded [symbolic = constants.%Self.013]
+// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.1db: %I.type = import_ref HasExtraInterfaces//default, inst66 [no loc], loaded [symbolic = constants.%Self.013]
 // CHECK:STDOUT:   %HasExtraInterfaces.import_ref.bca = import_ref HasExtraInterfaces//default, loc16_79, unloaded
-// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.9c8 = import_ref HasExtraInterfaces//default, inst45 [no loc], unloaded
-// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.dfe = import_ref HasExtraInterfaces//default, inst41 [no loc], unloaded
-// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.6b6 = import_ref HasExtraInterfaces//default, inst37 [no loc], unloaded
-// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.576 = import_ref HasExtraInterfaces//default, inst33 [no loc], unloaded
-// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.0dd = import_ref HasExtraInterfaces//default, inst29 [no loc], unloaded
-// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.f83 = import_ref HasExtraInterfaces//default, inst25 [no loc], unloaded
-// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.975 = import_ref HasExtraInterfaces//default, inst21 [no loc], unloaded
-// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.a3c = import_ref HasExtraInterfaces//default, inst17 [no loc], unloaded
+// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.9c8 = import_ref HasExtraInterfaces//default, inst47 [no loc], unloaded
+// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.dfe = import_ref HasExtraInterfaces//default, inst43 [no loc], unloaded
+// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.6b6 = import_ref HasExtraInterfaces//default, inst39 [no loc], unloaded
+// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.576 = import_ref HasExtraInterfaces//default, inst35 [no loc], unloaded
+// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.0dd = import_ref HasExtraInterfaces//default, inst31 [no loc], unloaded
+// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.f83 = import_ref HasExtraInterfaces//default, inst27 [no loc], unloaded
+// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.975 = import_ref HasExtraInterfaces//default, inst23 [no loc], unloaded
+// CHECK:STDOUT:   %HasExtraInterfaces.import_ref.a3c = import_ref HasExtraInterfaces//default, inst19 [no loc], unloaded
 // CHECK:STDOUT:   %HasExtraInterfaces.import_ref.aa8: type = import_ref HasExtraInterfaces//default, loc16_72, loaded [concrete = constants.%C.074]
 // CHECK:STDOUT:   %HasExtraInterfaces.import_ref.301: type = import_ref HasExtraInterfaces//default, loc16_77, loaded [concrete = constants.%I.type]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .HasExtraInterfaces = imports.%HasExtraInterfaces
 // CHECK:STDOUT:     .Test = %Test.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %HasExtraInterfaces.import = import HasExtraInterfaces
 // CHECK:STDOUT:   %Test.decl: %Test.type = fn_decl @Test [concrete = constants.%Test] {
 // CHECK:STDOUT:     %c.patt: %C.42e = binding_pattern c
@@ -2612,3 +2702,9 @@ fn Test(c: HasExtraInterfaces.C(type)) {
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/impl/no_prelude/fail_extend_impl_scope.carbon b/toolchain/check/testdata/impl/min_prelude/fail_extend_impl_scope.carbon
similarity index 90%
rename from toolchain/check/testdata/impl/no_prelude/fail_extend_impl_scope.carbon
rename to toolchain/check/testdata/impl/min_prelude/fail_extend_impl_scope.carbon
index 6ad92d86af12..a158432a93fa 100644
--- a/toolchain/check/testdata/impl/no_prelude/fail_extend_impl_scope.carbon
+++ b/toolchain/check/testdata/impl/min_prelude/fail_extend_impl_scope.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/impl/no_prelude/fail_extend_impl_scope.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/impl/min_prelude/fail_extend_impl_scope.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/impl/no_prelude/fail_extend_impl_scope.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/impl/min_prelude/fail_extend_impl_scope.carbon
 
 // --- fail_extend_impl_file_scope.carbon
 library "[[@TEST_NAME]]";
@@ -69,10 +72,18 @@ fn F() {
 // CHECK:STDOUT:   %I.impl_witness: <witness> = impl_witness file.%I.impl_witness_table [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .I = %I.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %I.decl: type = interface_decl @I [concrete = constants.%I.type] {} {}
 // CHECK:STDOUT:   impl_decl @impl [concrete] {} {
 // CHECK:STDOUT:     %.loc9_14.1: %empty_tuple.type = tuple_literal ()
@@ -107,11 +118,19 @@ fn F() {
 // CHECK:STDOUT:   %J.impl_witness: <witness> = impl_witness @F.%J.impl_witness_table [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .J = %J.decl
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %J.decl: type = interface_decl @J [concrete = constants.%J.type] {} {}
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
 // CHECK:STDOUT: }
@@ -166,12 +185,20 @@ fn F() {
 // CHECK:STDOUT:   %.766: type = fn_type_with_self_type %Zero.type.822, %Z.facet [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Z = %Z.decl
 // CHECK:STDOUT:     .Point = %Point.decl
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Z.decl: type = interface_decl @Z [concrete = constants.%Z.type] {} {}
 // CHECK:STDOUT:   %Point.decl: type = class_decl @Point [concrete = constants.%Point] {} {}
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
@@ -281,3 +308,9 @@ fn F() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: specific @Zero.1(constants.%Z.facet) {}
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/impl/no_prelude/fail_impl_as_scope.carbon b/toolchain/check/testdata/impl/min_prelude/fail_impl_as_scope.carbon
similarity index 94%
rename from toolchain/check/testdata/impl/no_prelude/fail_impl_as_scope.carbon
rename to toolchain/check/testdata/impl/min_prelude/fail_impl_as_scope.carbon
index 852ae9041b69..cd1d2365ccbc 100644
--- a/toolchain/check/testdata/impl/no_prelude/fail_impl_as_scope.carbon
+++ b/toolchain/check/testdata/impl/min_prelude/fail_impl_as_scope.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/impl/no_prelude/fail_impl_as_scope.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/impl/min_prelude/fail_impl_as_scope.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/impl/no_prelude/fail_impl_as_scope.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/impl/min_prelude/fail_impl_as_scope.carbon
 
 // --- fail_impl_as_file_scope.carbon
 library "[[@TEST_NAME]]";
@@ -107,12 +110,20 @@ class X {
 // CHECK:STDOUT:   %F: %F.type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .I = %I.decl
 // CHECK:STDOUT:     .G = %G.decl
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %I.decl: type = interface_decl @I [concrete = constants.%I.type] {} {}
 // CHECK:STDOUT:   %G.decl: %G.type = fn_decl @G [concrete = constants.%G] {} {}
 // CHECK:STDOUT:   impl_decl @impl [concrete] {} {
@@ -159,12 +170,20 @@ class X {
 // CHECK:STDOUT:   %F: %F.type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .J = %J.decl
 // CHECK:STDOUT:     .G = %G.decl
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %J.decl: type = interface_decl @J [concrete = constants.%J.type] {} {}
 // CHECK:STDOUT:   %G.decl: %G.type = fn_decl @G [concrete = constants.%G] {} {}
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
@@ -234,12 +253,20 @@ class X {
 // CHECK:STDOUT:   %.462: type = fn_type_with_self_type %Method.type.f12, %Z.facet [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Z = %Z.decl
 // CHECK:STDOUT:     .Point = %Point.decl
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Z.decl: type = interface_decl @Z [concrete = constants.%Z.type] {} {}
 // CHECK:STDOUT:   %Point.decl: type = class_decl @Point [concrete = constants.%Point] {} {}
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
@@ -460,13 +487,21 @@ class X {
 // CHECK:STDOUT:   %complete_type: <witness> = complete_type_witness %empty_struct_type [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .A = %A.decl
 // CHECK:STDOUT:     .C = %C.decl
 // CHECK:STDOUT:     .G = %G.decl
 // CHECK:STDOUT:     .X = %X.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %A.decl: type = interface_decl @A [concrete = constants.%A.type] {} {}
 // CHECK:STDOUT:   %C.decl: type = interface_decl @C [concrete = constants.%C.type] {} {}
 // CHECK:STDOUT:   %G.decl: %G.type = fn_decl @G [concrete = constants.%G] {} {}
@@ -549,3 +584,9 @@ class X {
 // CHECK:STDOUT:
 // CHECK:STDOUT: specific @B.1(constants.%A.facet) {}
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/impl/no_prelude/generic_redeclaration.carbon b/toolchain/check/testdata/impl/min_prelude/generic_redeclaration.carbon
similarity index 96%
rename from toolchain/check/testdata/impl/no_prelude/generic_redeclaration.carbon
rename to toolchain/check/testdata/impl/min_prelude/generic_redeclaration.carbon
index 073315d3bba5..6e7ca3099179 100644
--- a/toolchain/check/testdata/impl/no_prelude/generic_redeclaration.carbon
+++ b/toolchain/check/testdata/impl/min_prelude/generic_redeclaration.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/impl/no_prelude/generic_redeclaration.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/impl/min_prelude/generic_redeclaration.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/impl/no_prelude/generic_redeclaration.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/impl/min_prelude/generic_redeclaration.carbon
 
 // --- same_self_and_interface.carbon
 
@@ -120,14 +123,22 @@ impl forall [T:! type] T as I {
 // CHECK:STDOUT:   %Interface.impl_witness.e9d: <witness> = impl_witness file.%Interface.impl_witness_table.loc14, @impl.9e6(%T.1d2) [symbolic]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Interface = %Interface.decl
 // CHECK:STDOUT:     .I = %I.decl
 // CHECK:STDOUT:     .J = %J.decl
 // CHECK:STDOUT:     .K = %K.decl
 // CHECK:STDOUT:     .L = %L.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Interface.decl: type = interface_decl @Interface [concrete = constants.%Interface.type] {} {}
 // CHECK:STDOUT:   %I.decl: type = interface_decl @I [concrete = constants.%I.type] {} {}
 // CHECK:STDOUT:   %J.decl: type = interface_decl @J [concrete = constants.%J.type] {} {}
@@ -369,11 +380,19 @@ impl forall [T:! type] T as I {
 // CHECK:STDOUT:   %J.impl_witness.a529f4.2: <witness> = impl_witness file.%J.impl_witness_table.loc15, @impl.bfd509.2(%T) [symbolic]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .I = %I.decl
 // CHECK:STDOUT:     .J = %J.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %I.decl: type = interface_decl @I [concrete = constants.%I.type] {} {}
 // CHECK:STDOUT:   %J.decl: type = interface_decl @J [concrete = constants.%J.type] {} {}
 // CHECK:STDOUT:   impl_decl @impl.bfd509.1 [concrete] {
@@ -477,11 +496,19 @@ impl forall [T:! type] T as I {
 // CHECK:STDOUT:   %I.impl_witness.215123.2: <witness> = impl_witness file.%I.impl_witness_table.loc14 [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .C = %C.decl
 // CHECK:STDOUT:     .I = %I.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %C.decl: type = class_decl @C [concrete = constants.%C] {} {}
 // CHECK:STDOUT:   %I.decl: type = interface_decl @I [concrete = constants.%I.type] {} {}
 // CHECK:STDOUT:   impl_decl @impl.7704ae.1 [concrete] {} {
@@ -546,10 +573,18 @@ impl forall [T:! type] T as I {
 // CHECK:STDOUT:   %C.specific_fn: <specific function> = specific_function %C, @C(%T) [symbolic]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .I = %I.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %I.decl: type = interface_decl @I [concrete = constants.%I.type] {} {}
 // CHECK:STDOUT:   impl_decl @impl.2caff2.1 [concrete] {
 // CHECK:STDOUT:     %T.patt.loc4_14.1: type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc4_14.2 (constants.%T.patt)]
@@ -732,3 +767,9 @@ impl forall [T:! type] T as I {
 // CHECK:STDOUT:
 // CHECK:STDOUT: specific @C(@D.%T) {}
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/impl/no_prelude/import_self.carbon b/toolchain/check/testdata/impl/min_prelude/import_self.carbon
similarity index 93%
rename from toolchain/check/testdata/impl/no_prelude/import_self.carbon
rename to toolchain/check/testdata/impl/min_prelude/import_self.carbon
index d5c06c36676c..00d3e234a348 100644
--- a/toolchain/check/testdata/impl/no_prelude/import_self.carbon
+++ b/toolchain/check/testdata/impl/min_prelude/import_self.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/impl/no_prelude/import_self.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/impl/min_prelude/import_self.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/impl/no_prelude/import_self.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/impl/min_prelude/import_self.carbon
 
 // --- a.carbon
 
@@ -42,10 +45,18 @@ fn F(x: (), y: ()) -> () {
 // CHECK:STDOUT:   %assoc0: %Add.assoc_type = assoc_entity element0, @Add.%Op.decl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Add = %Add.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Add.decl: type = interface_decl @Add [concrete = constants.%Add.type] {} {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -122,17 +133,22 @@ fn F(x: (), y: ()) -> () {
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
 // CHECK:STDOUT:   %Main.Add: type = import_ref Main//a, Add, loaded [concrete = constants.%Add.type]
-// CHECK:STDOUT:   %Main.import_ref.07c = import_ref Main//a, inst17 [no loc], unloaded
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Main.import_ref.07c = import_ref Main//a, inst19 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.f99: %Add.assoc_type = import_ref Main//a, loc5_41, loaded [concrete = constants.%assoc0]
 // CHECK:STDOUT:   %Main.Op: %Op.type.31b = import_ref Main//a, Op, loaded [concrete = constants.%Op.d59]
-// CHECK:STDOUT:   %Main.import_ref.e5e: %Add.type = import_ref Main//a, inst17 [no loc], loaded [symbolic = constants.%Self]
+// CHECK:STDOUT:   %Main.import_ref.e5e: %Add.type = import_ref Main//a, inst19 [no loc], loaded [symbolic = constants.%Self]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
 // CHECK:STDOUT:     .Add = imports.%Main.Add
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %default.import = import <none>
 // CHECK:STDOUT:   impl_decl @impl [concrete] {} {
 // CHECK:STDOUT:     %.loc6_7.1: %empty_tuple.type = tuple_literal ()
@@ -241,3 +257,9 @@ fn F(x: (), y: ()) -> () {
 // CHECK:STDOUT:   %Self.as_type => constants.%empty_tuple.type
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/impl/no_prelude/interface_args.carbon b/toolchain/check/testdata/impl/min_prelude/interface_args.carbon
similarity index 97%
rename from toolchain/check/testdata/impl/no_prelude/interface_args.carbon
rename to toolchain/check/testdata/impl/min_prelude/interface_args.carbon
index 6fd517fd16c0..671a39851a71 100644
--- a/toolchain/check/testdata/impl/no_prelude/interface_args.carbon
+++ b/toolchain/check/testdata/impl/min_prelude/interface_args.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/impl/no_prelude/interface_args.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/impl/min_prelude/interface_args.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/impl/no_prelude/interface_args.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/impl/min_prelude/interface_args.carbon
 
 // --- core.carbon
 package Core;
@@ -232,14 +235,22 @@ fn InstanceC(a: A) -> C {
 // CHECK:STDOUT:   %.584: type = fn_type_with_self_type %Op.type.54d, %Action.facet [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Action = %Action.decl
 // CHECK:STDOUT:     .A = %A.decl
 // CHECK:STDOUT:     .B = %B.decl
 // CHECK:STDOUT:     .C = %C.decl
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Action.decl: %Action.type.29c = interface_decl @Action [concrete = constants.%Action.generic] {
 // CHECK:STDOUT:     %T.patt.loc4_18.1: type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc4_18.2 (constants.%T.patt)]
 // CHECK:STDOUT:   } {
@@ -450,20 +461,23 @@ fn InstanceC(a: A) -> C {
 // CHECK:STDOUT:   %Main.B: type = import_ref Main//action, B, loaded [concrete = constants.%B]
 // CHECK:STDOUT:   %Main.C = import_ref Main//action, C, unloaded
 // CHECK:STDOUT:   %Main.F = import_ref Main//action, F, unloaded
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Main.import_ref.8f24d3.1: <witness> = import_ref Main//action, loc9_10, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %Main.import_ref.54a = import_ref Main//action, inst61 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.54a = import_ref Main//action, inst63 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.5ab3ec.1: type = import_ref Main//action, loc4_18, loaded [symbolic = @Action.%T (constants.%T)]
-// CHECK:STDOUT:   %Main.import_ref.ddc = import_ref Main//action, inst26 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.ddc = import_ref Main//action, inst28 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.c55: @Action.%Action.assoc_type (%Action.assoc_type.32e) = import_ref Main//action, loc5_22, loaded [symbolic = @Action.%assoc0 (constants.%assoc0.f18741.2)]
 // CHECK:STDOUT:   %Main.Op = import_ref Main//action, Op, unloaded
 // CHECK:STDOUT:   %Main.import_ref.995: <witness> = import_ref Main//action, loc12_21, loaded [concrete = constants.%Action.impl_witness]
 // CHECK:STDOUT:   %Main.import_ref.8f24d3.2: <witness> = import_ref Main//action, loc8_10, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %Main.import_ref.da3 = import_ref Main//action, inst55 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.da3 = import_ref Main//action, inst57 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.984: type = import_ref Main//action, loc12_6, loaded [concrete = constants.%A]
 // CHECK:STDOUT:   %Main.import_ref.bb2: type = import_ref Main//action, loc12_19, loaded [concrete = constants.%Action.type.cb0]
 // CHECK:STDOUT:   %Main.import_ref.7b5 = import_ref Main//action, loc13_23, unloaded
 // CHECK:STDOUT:   %Main.import_ref.5ab3ec.2: type = import_ref Main//action, loc4_18, loaded [symbolic = @Action.%T (constants.%T)]
-// CHECK:STDOUT:   %Main.import_ref.835: @Action.%Action.type (%Action.type.cca) = import_ref Main//action, inst26 [no loc], loaded [symbolic = @Action.%Self (constants.%Self.e98)]
+// CHECK:STDOUT:   %Main.import_ref.835: @Action.%Action.type (%Action.type.cca) = import_ref Main//action, inst28 [no loc], loaded [symbolic = @Action.%Self (constants.%Self.e98)]
 // CHECK:STDOUT:   %Main.import_ref.0e3753.1 = import_ref Main//action, loc5_22, unloaded
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -474,10 +488,12 @@ fn InstanceC(a: A) -> C {
 // CHECK:STDOUT:     .B = imports.%Main.B
 // CHECK:STDOUT:     .C = imports.%Main.C
 // CHECK:STDOUT:     .F = imports.%Main.F
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .G = %G.decl
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %default.import.loc2_22.1 = import <none>
 // CHECK:STDOUT:   %default.import.loc2_22.2 = import <none>
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %G.decl: %G.type = fn_decl @G [concrete = constants.%G] {
 // CHECK:STDOUT:     %a.patt: %A = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %A = value_param_pattern %a.patt, call_param0
@@ -624,23 +640,26 @@ fn InstanceC(a: A) -> C {
 // CHECK:STDOUT:   %Main.B = import_ref Main//action, B, unloaded
 // CHECK:STDOUT:   %Main.C: type = import_ref Main//action, C, loaded [concrete = constants.%C]
 // CHECK:STDOUT:   %Main.F = import_ref Main//action, F, unloaded
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Main.import_ref.8f24d3.1: <witness> = import_ref Main//action, loc9_10, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %Main.import_ref.54a = import_ref Main//action, inst61 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.54a = import_ref Main//action, inst63 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.5ab3ec.1: type = import_ref Main//action, loc4_18, loaded [symbolic = @Action.%T (constants.%T)]
-// CHECK:STDOUT:   %Main.import_ref.ddc = import_ref Main//action, inst26 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.ddc = import_ref Main//action, inst28 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.c55: @Action.%Action.assoc_type (%Action.assoc_type.32e) = import_ref Main//action, loc5_22, loaded [symbolic = @Action.%assoc0 (constants.%assoc0.f18)]
 // CHECK:STDOUT:   %Main.Op = import_ref Main//action, Op, unloaded
 // CHECK:STDOUT:   %Main.import_ref.19c = import_ref Main//action, loc12_21, unloaded
 // CHECK:STDOUT:   %Main.import_ref.8f24d3.2: <witness> = import_ref Main//action, loc8_10, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %Main.import_ref.da3 = import_ref Main//action, inst55 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.da3 = import_ref Main//action, inst57 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.984: type = import_ref Main//action, loc12_6, loaded [concrete = constants.%A]
 // CHECK:STDOUT:   %Main.import_ref.bb2: type = import_ref Main//action, loc12_19, loaded [concrete = constants.%Action.type.cb0]
 // CHECK:STDOUT:   %Main.import_ref.7b5 = import_ref Main//action, loc13_23, unloaded
 // CHECK:STDOUT:   %Main.import_ref.5ab3ec.2: type = import_ref Main//action, loc4_18, loaded [symbolic = @Action.%T (constants.%T)]
-// CHECK:STDOUT:   %Main.import_ref.835: @Action.%Action.type (%Action.type.cca) = import_ref Main//action, inst26 [no loc], loaded [symbolic = @Action.%Self (constants.%Self.e98)]
+// CHECK:STDOUT:   %Main.import_ref.835: @Action.%Action.type (%Action.type.cca) = import_ref Main//action, inst28 [no loc], loaded [symbolic = @Action.%Self (constants.%Self.e98)]
 // CHECK:STDOUT:   %Main.import_ref.1f6: @Action.%Op.type (%Op.type.036) = import_ref Main//action, loc5_22, loaded [symbolic = @Action.%Op (constants.%Op.6ed)]
 // CHECK:STDOUT:   %Main.import_ref.8f24d3.3: <witness> = import_ref Main//action, loc10_10, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %Main.import_ref.2c4 = import_ref Main//action, inst65 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.2c4 = import_ref Main//action, inst67 [no loc], unloaded
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
@@ -650,10 +669,12 @@ fn InstanceC(a: A) -> C {
 // CHECK:STDOUT:     .B = imports.%Main.B
 // CHECK:STDOUT:     .C = imports.%Main.C
 // CHECK:STDOUT:     .F = imports.%Main.F
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .G = %G.decl
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %default.import.loc2_22.1 = import <none>
 // CHECK:STDOUT:   %default.import.loc2_22.2 = import <none>
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %G.decl: %G.type = fn_decl @G [concrete = constants.%G] {
 // CHECK:STDOUT:     %a.patt: %A = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %A = value_param_pattern %a.patt, call_param0
@@ -811,12 +832,20 @@ fn InstanceC(a: A) -> C {
 // CHECK:STDOUT:   %Factory.facet: %Factory.type.a5d = facet_value %A, (%Factory.impl_witness) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Factory = %Factory.decl
 // CHECK:STDOUT:     .A = %A.decl
 // CHECK:STDOUT:     .B = %B.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Factory.decl: %Factory.type.1a8 = interface_decl @Factory [concrete = constants.%Factory.generic] {
 // CHECK:STDOUT:     %T.patt.loc4_19.1: type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc4_19.2 (constants.%T.patt)]
 // CHECK:STDOUT:   } {
@@ -1054,26 +1083,29 @@ fn InstanceC(a: A) -> C {
 // CHECK:STDOUT:   %Main.Factory: %Factory.type.1a8 = import_ref Main//factory, Factory, loaded [concrete = constants.%Factory.generic]
 // CHECK:STDOUT:   %Main.A: type = import_ref Main//factory, A, loaded [concrete = constants.%A]
 // CHECK:STDOUT:   %Main.B: type = import_ref Main//factory, B, loaded [concrete = constants.%B]
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Main.import_ref.8f24d3.1: <witness> = import_ref Main//factory, loc12_10, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %Main.import_ref.54a = import_ref Main//factory, inst80 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.54a = import_ref Main//factory, inst82 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.5ab3ec.1: type = import_ref Main//factory, loc4_19, loaded [symbolic = @Factory.%T (constants.%T)]
-// CHECK:STDOUT:   %Main.import_ref.fbb = import_ref Main//factory, inst26 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.fbb = import_ref Main//factory, inst28 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.46c: @Factory.%Factory.assoc_type (%Factory.assoc_type.207) = import_ref Main//factory, loc6_17, loaded [symbolic = @Factory.%assoc0 (constants.%assoc0.46d25f.2)]
 // CHECK:STDOUT:   %Main.import_ref.2e4: @Factory.%Factory.assoc_type (%Factory.assoc_type.207) = import_ref Main//factory, loc8_31, loaded [symbolic = @Factory.%assoc1 (constants.%assoc1.16541d.2)]
 // CHECK:STDOUT:   %Main.Make = import_ref Main//factory, Make, unloaded
 // CHECK:STDOUT:   %Main.Method = import_ref Main//factory, Method, unloaded
 // CHECK:STDOUT:   %Main.import_ref.6fd: <witness> = import_ref Main//factory, loc14_22, loaded [concrete = constants.%Factory.impl_witness]
 // CHECK:STDOUT:   %Main.import_ref.8f24d3.2: <witness> = import_ref Main//factory, loc11_10, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %Main.import_ref.da3 = import_ref Main//factory, inst74 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.da3 = import_ref Main//factory, inst76 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.984: type = import_ref Main//factory, loc14_6, loaded [concrete = constants.%A]
 // CHECK:STDOUT:   %Main.import_ref.bd2: type = import_ref Main//factory, loc14_20, loaded [concrete = constants.%Factory.type.a5d]
 // CHECK:STDOUT:   %Main.import_ref.a27 = import_ref Main//factory, loc15_17, unloaded
 // CHECK:STDOUT:   %Main.import_ref.163 = import_ref Main//factory, loc16_31, unloaded
 // CHECK:STDOUT:   %Main.import_ref.5ab3ec.2: type = import_ref Main//factory, loc4_19, loaded [symbolic = @Factory.%T (constants.%T)]
-// CHECK:STDOUT:   %Main.import_ref.91b53a.1: @Factory.%Factory.type (%Factory.type.c96) = import_ref Main//factory, inst26 [no loc], loaded [symbolic = @Factory.%Self (constants.%Self.9ba)]
+// CHECK:STDOUT:   %Main.import_ref.91b53a.1: @Factory.%Factory.type (%Factory.type.c96) = import_ref Main//factory, inst28 [no loc], loaded [symbolic = @Factory.%Self (constants.%Self.9ba)]
 // CHECK:STDOUT:   %Main.import_ref.21018a.1 = import_ref Main//factory, loc6_17, unloaded
 // CHECK:STDOUT:   %Main.import_ref.5ab3ec.3: type = import_ref Main//factory, loc4_19, loaded [symbolic = @Factory.%T (constants.%T)]
-// CHECK:STDOUT:   %Main.import_ref.91b53a.2: @Factory.%Factory.type (%Factory.type.c96) = import_ref Main//factory, inst26 [no loc], loaded [symbolic = @Factory.%Self (constants.%Self.9ba)]
+// CHECK:STDOUT:   %Main.import_ref.91b53a.2: @Factory.%Factory.type (%Factory.type.c96) = import_ref Main//factory, inst28 [no loc], loaded [symbolic = @Factory.%Self (constants.%Self.9ba)]
 // CHECK:STDOUT:   %Main.import_ref.46fc3c.1 = import_ref Main//factory, loc8_31, unloaded
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -1082,11 +1114,13 @@ fn InstanceC(a: A) -> C {
 // CHECK:STDOUT:     .Factory = imports.%Main.Factory
 // CHECK:STDOUT:     .A = imports.%Main.A
 // CHECK:STDOUT:     .B = imports.%Main.B
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .MakeB = %MakeB.decl
 // CHECK:STDOUT:     .InstanceB = %InstanceB.decl
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %default.import.loc2_23.1 = import <none>
 // CHECK:STDOUT:   %default.import.loc2_23.2 = import <none>
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %MakeB.decl: %MakeB.type = fn_decl @MakeB [concrete = constants.%MakeB] {
 // CHECK:STDOUT:     %return.patt: %B = return_slot_pattern
 // CHECK:STDOUT:     %return.param_patt: %B = out_param_pattern %return.patt, call_param0
@@ -1294,28 +1328,29 @@ fn InstanceC(a: A) -> C {
 // CHECK:STDOUT:   %Main.A: type = import_ref Main//factory, A, loaded [concrete = constants.%A]
 // CHECK:STDOUT:   %Main.B = import_ref Main//factory, B, unloaded
 // CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
 // CHECK:STDOUT:     import Core//default
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Main.import_ref.8f24d3.1: <witness> = import_ref Main//factory, loc12_10, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %Main.import_ref.54a = import_ref Main//factory, inst80 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.54a = import_ref Main//factory, inst82 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.5ab3ec.1: type = import_ref Main//factory, loc4_19, loaded [symbolic = @Factory.%T (constants.%T)]
-// CHECK:STDOUT:   %Main.import_ref.fbb = import_ref Main//factory, inst26 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.fbb = import_ref Main//factory, inst28 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.46c: @Factory.%Factory.assoc_type (%Factory.assoc_type.207) = import_ref Main//factory, loc6_17, loaded [symbolic = @Factory.%assoc0 (constants.%assoc0.46d)]
 // CHECK:STDOUT:   %Main.import_ref.2e4: @Factory.%Factory.assoc_type (%Factory.assoc_type.207) = import_ref Main//factory, loc8_31, loaded [symbolic = @Factory.%assoc1 (constants.%assoc1.165)]
 // CHECK:STDOUT:   %Main.Make = import_ref Main//factory, Make, unloaded
 // CHECK:STDOUT:   %Main.Method = import_ref Main//factory, Method, unloaded
 // CHECK:STDOUT:   %Main.import_ref.4c3 = import_ref Main//factory, loc14_22, unloaded
 // CHECK:STDOUT:   %Main.import_ref.8f24d3.2: <witness> = import_ref Main//factory, loc11_10, loaded [concrete = constants.%complete_type]
-// CHECK:STDOUT:   %Main.import_ref.da3 = import_ref Main//factory, inst74 [no loc], unloaded
+// CHECK:STDOUT:   %Main.import_ref.da3 = import_ref Main//factory, inst76 [no loc], unloaded
 // CHECK:STDOUT:   %Main.import_ref.984: type = import_ref Main//factory, loc14_6, loaded [concrete = constants.%A]
 // CHECK:STDOUT:   %Main.import_ref.bd2: type = import_ref Main//factory, loc14_20, loaded [concrete = constants.%Factory.type.a5d]
 // CHECK:STDOUT:   %Main.import_ref.a27 = import_ref Main//factory, loc15_17, unloaded
 // CHECK:STDOUT:   %Main.import_ref.163 = import_ref Main//factory, loc16_31, unloaded
 // CHECK:STDOUT:   %Main.import_ref.5ab3ec.2: type = import_ref Main//factory, loc4_19, loaded [symbolic = @Factory.%T (constants.%T)]
-// CHECK:STDOUT:   %Main.import_ref.91b53a.1: @Factory.%Factory.type (%Factory.type.c96) = import_ref Main//factory, inst26 [no loc], loaded [symbolic = @Factory.%Self (constants.%Self.9ba)]
+// CHECK:STDOUT:   %Main.import_ref.91b53a.1: @Factory.%Factory.type (%Factory.type.c96) = import_ref Main//factory, inst28 [no loc], loaded [symbolic = @Factory.%Self (constants.%Self.9ba)]
 // CHECK:STDOUT:   %Main.import_ref.1aa: @Factory.%Make.type (%Make.type.598) = import_ref Main//factory, loc6_17, loaded [symbolic = @Factory.%Make (constants.%Make.737)]
 // CHECK:STDOUT:   %Main.import_ref.5ab3ec.3: type = import_ref Main//factory, loc4_19, loaded [symbolic = @Factory.%T (constants.%T)]
-// CHECK:STDOUT:   %Main.import_ref.91b53a.2: @Factory.%Factory.type (%Factory.type.c96) = import_ref Main//factory, inst26 [no loc], loaded [symbolic = @Factory.%Self (constants.%Self.9ba)]
+// CHECK:STDOUT:   %Main.import_ref.91b53a.2: @Factory.%Factory.type (%Factory.type.c96) = import_ref Main//factory, inst28 [no loc], loaded [symbolic = @Factory.%Self (constants.%Self.9ba)]
 // CHECK:STDOUT:   %Main.import_ref.5be: @Factory.%Method.type (%Method.type.7ee) = import_ref Main//factory, loc8_31, loaded [symbolic = @Factory.%Method (constants.%Method.a71)]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -1499,3 +1534,9 @@ fn InstanceC(a: A) -> C {
 // CHECK:STDOUT:   %assoc1 => constants.%assoc1.263
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/interface/no_prelude/as_type_of_type.carbon b/toolchain/check/testdata/interface/min_prelude/as_type_of_type.carbon
similarity index 53%
rename from toolchain/check/testdata/interface/no_prelude/as_type_of_type.carbon
rename to toolchain/check/testdata/interface/min_prelude/as_type_of_type.carbon
index ddac8d2188d6..6dda99a9b795 100644
--- a/toolchain/check/testdata/interface/no_prelude/as_type_of_type.carbon
+++ b/toolchain/check/testdata/interface/min_prelude/as_type_of_type.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interface/no_prelude/as_type_of_type.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interface/min_prelude/as_type_of_type.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interface/no_prelude/as_type_of_type.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interface/min_prelude/as_type_of_type.carbon
 
 interface Empty {}
 
@@ -27,17 +30,25 @@ fn F(T:! Empty) {
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type %T.as_type [symbolic]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Empty = %Empty.decl
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Empty.decl: type = interface_decl @Empty [concrete = constants.%Empty.type] {} {}
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {
-// CHECK:STDOUT:     %T.patt.loc13_6.1: %Empty.type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc13_6.2 (constants.%T.patt)]
+// CHECK:STDOUT:     %T.patt.loc16_6.1: %Empty.type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc16_6.2 (constants.%T.patt)]
 // CHECK:STDOUT:   } {
 // CHECK:STDOUT:     %Empty.ref: type = name_ref Empty, file.%Empty.decl [concrete = constants.%Empty.type]
-// CHECK:STDOUT:     %T.loc13_6.1: %Empty.type = bind_symbolic_name T, 0 [symbolic = %T.loc13_6.2 (constants.%T)]
+// CHECK:STDOUT:     %T.loc16_6.1: %Empty.type = bind_symbolic_name T, 0 [symbolic = %T.loc16_6.2 (constants.%T)]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -49,33 +60,39 @@ fn F(T:! Empty) {
 // CHECK:STDOUT:   witness = ()
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: generic fn @F(%T.loc13_6.1: %Empty.type) {
-// CHECK:STDOUT:   %T.loc13_6.2: %Empty.type = bind_symbolic_name T, 0 [symbolic = %T.loc13_6.2 (constants.%T)]
-// CHECK:STDOUT:   %T.patt.loc13_6.2: %Empty.type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc13_6.2 (constants.%T.patt)]
+// CHECK:STDOUT: generic fn @F(%T.loc16_6.1: %Empty.type) {
+// CHECK:STDOUT:   %T.loc16_6.2: %Empty.type = bind_symbolic_name T, 0 [symbolic = %T.loc16_6.2 (constants.%T)]
+// CHECK:STDOUT:   %T.patt.loc16_6.2: %Empty.type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc16_6.2 (constants.%T.patt)]
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
-// CHECK:STDOUT:   %T.as_type.loc14_10.2: type = facet_access_type %T.loc13_6.2 [symbolic = %T.as_type.loc14_10.2 (constants.%T.as_type)]
-// CHECK:STDOUT:   %require_complete: <witness> = require_complete_type %T.as_type.loc14_10.2 [symbolic = %require_complete (constants.%require_complete)]
+// CHECK:STDOUT:   %T.as_type.loc17_10.2: type = facet_access_type %T.loc16_6.2 [symbolic = %T.as_type.loc17_10.2 (constants.%T.as_type)]
+// CHECK:STDOUT:   %require_complete: <witness> = require_complete_type %T.as_type.loc17_10.2 [symbolic = %require_complete (constants.%require_complete)]
 // CHECK:STDOUT:
 // CHECK:STDOUT:   fn() {
 // CHECK:STDOUT:   !entry:
 // CHECK:STDOUT:     name_binding_decl {
-// CHECK:STDOUT:       %x.patt: @F.%T.as_type.loc14_10.2 (%T.as_type) = binding_pattern x
-// CHECK:STDOUT:       %.loc14_3: @F.%T.as_type.loc14_10.2 (%T.as_type) = var_pattern %x.patt
+// CHECK:STDOUT:       %x.patt: @F.%T.as_type.loc17_10.2 (%T.as_type) = binding_pattern x
+// CHECK:STDOUT:       %.loc17_3: @F.%T.as_type.loc17_10.2 (%T.as_type) = var_pattern %x.patt
 // CHECK:STDOUT:     }
-// CHECK:STDOUT:     %x.var: ref @F.%T.as_type.loc14_10.2 (%T.as_type) = var x
-// CHECK:STDOUT:     %.loc14_10.1: type = splice_block %.loc14_10.2 [symbolic = %T.as_type.loc14_10.2 (constants.%T.as_type)] {
-// CHECK:STDOUT:       %T.ref: %Empty.type = name_ref T, %T.loc13_6.1 [symbolic = %T.loc13_6.2 (constants.%T)]
-// CHECK:STDOUT:       %T.as_type.loc14_10.1: type = facet_access_type %T.ref [symbolic = %T.as_type.loc14_10.2 (constants.%T.as_type)]
-// CHECK:STDOUT:       %.loc14_10.2: type = converted %T.ref, %T.as_type.loc14_10.1 [symbolic = %T.as_type.loc14_10.2 (constants.%T.as_type)]
+// CHECK:STDOUT:     %x.var: ref @F.%T.as_type.loc17_10.2 (%T.as_type) = var x
+// CHECK:STDOUT:     %.loc17_10.1: type = splice_block %.loc17_10.2 [symbolic = %T.as_type.loc17_10.2 (constants.%T.as_type)] {
+// CHECK:STDOUT:       %T.ref: %Empty.type = name_ref T, %T.loc16_6.1 [symbolic = %T.loc16_6.2 (constants.%T)]
+// CHECK:STDOUT:       %T.as_type.loc17_10.1: type = facet_access_type %T.ref [symbolic = %T.as_type.loc17_10.2 (constants.%T.as_type)]
+// CHECK:STDOUT:       %.loc17_10.2: type = converted %T.ref, %T.as_type.loc17_10.1 [symbolic = %T.as_type.loc17_10.2 (constants.%T.as_type)]
 // CHECK:STDOUT:     }
-// CHECK:STDOUT:     %x: ref @F.%T.as_type.loc14_10.2 (%T.as_type) = bind_name x, %x.var
+// CHECK:STDOUT:     %x: ref @F.%T.as_type.loc17_10.2 (%T.as_type) = bind_name x, %x.var
 // CHECK:STDOUT:     return
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: specific @F(constants.%T) {
-// CHECK:STDOUT:   %T.loc13_6.2 => constants.%T
-// CHECK:STDOUT:   %T.patt.loc13_6.2 => constants.%T.patt
+// CHECK:STDOUT:   %T.loc16_6.2 => constants.%T
+// CHECK:STDOUT:   %T.patt.loc16_6.2 => constants.%T.patt
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
diff --git a/toolchain/check/testdata/interface/no_prelude/default_fn.carbon b/toolchain/check/testdata/interface/min_prelude/default_fn.carbon
similarity index 75%
rename from toolchain/check/testdata/interface/no_prelude/default_fn.carbon
rename to toolchain/check/testdata/interface/min_prelude/default_fn.carbon
index 57c290777dd4..845b65829658 100644
--- a/toolchain/check/testdata/interface/no_prelude/default_fn.carbon
+++ b/toolchain/check/testdata/interface/min_prelude/default_fn.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interface/no_prelude/default_fn.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interface/min_prelude/default_fn.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interface/no_prelude/default_fn.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interface/min_prelude/default_fn.carbon
 
 class C {
   interface I {
@@ -46,26 +49,34 @@ class C {
 // CHECK:STDOUT:   %.e5b: type = fn_type_with_self_type %F.type.0b5, %I.facet [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .C = %C.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %C.decl: type = class_decl @C [concrete = constants.%C] {} {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: interface @I {
 // CHECK:STDOUT:   %Self: %I.type = bind_symbolic_name Self, 0 [symbolic = constants.%Self]
 // CHECK:STDOUT:   %F.decl: %F.type.0b5 = fn_decl @F.1 [concrete = constants.%F.20c] {
-// CHECK:STDOUT:     %self.patt: @F.1.%Self.as_type.loc14_16.1 (%Self.as_type) = binding_pattern self
-// CHECK:STDOUT:     %self.param_patt: @F.1.%Self.as_type.loc14_16.1 (%Self.as_type) = value_param_pattern %self.patt, call_param0
+// CHECK:STDOUT:     %self.patt: @F.1.%Self.as_type.loc17_16.1 (%Self.as_type) = binding_pattern self
+// CHECK:STDOUT:     %self.param_patt: @F.1.%Self.as_type.loc17_16.1 (%Self.as_type) = value_param_pattern %self.patt, call_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %self.param: @F.1.%Self.as_type.loc14_16.1 (%Self.as_type) = value_param call_param0
-// CHECK:STDOUT:     %.loc14_16.1: type = splice_block %.loc14_16.2 [symbolic = %Self.as_type.loc14_16.1 (constants.%Self.as_type)] {
+// CHECK:STDOUT:     %self.param: @F.1.%Self.as_type.loc17_16.1 (%Self.as_type) = value_param call_param0
+// CHECK:STDOUT:     %.loc17_16.1: type = splice_block %.loc17_16.2 [symbolic = %Self.as_type.loc17_16.1 (constants.%Self.as_type)] {
 // CHECK:STDOUT:       %Self.ref: %I.type = name_ref Self, @I.%Self [symbolic = %Self (constants.%Self)]
-// CHECK:STDOUT:       %Self.as_type.loc14_16.2: type = facet_access_type %Self.ref [symbolic = %Self.as_type.loc14_16.1 (constants.%Self.as_type)]
-// CHECK:STDOUT:       %.loc14_16.2: type = converted %Self.ref, %Self.as_type.loc14_16.2 [symbolic = %Self.as_type.loc14_16.1 (constants.%Self.as_type)]
+// CHECK:STDOUT:       %Self.as_type.loc17_16.2: type = facet_access_type %Self.ref [symbolic = %Self.as_type.loc17_16.1 (constants.%Self.as_type)]
+// CHECK:STDOUT:       %.loc17_16.2: type = converted %Self.ref, %Self.as_type.loc17_16.2 [symbolic = %Self.as_type.loc17_16.1 (constants.%Self.as_type)]
 // CHECK:STDOUT:     }
-// CHECK:STDOUT:     %self: @F.1.%Self.as_type.loc14_16.1 (%Self.as_type) = bind_name self, %self.param
+// CHECK:STDOUT:     %self: @F.1.%Self.as_type.loc17_16.1 (%Self.as_type) = bind_name self, %self.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %assoc0: %I.assoc_type = assoc_entity element0, %F.decl [concrete = constants.%assoc0]
 // CHECK:STDOUT:
@@ -112,22 +123,22 @@ class C {
 // CHECK:STDOUT:
 // CHECK:STDOUT: generic fn @F.1(@I.%Self: %I.type) {
 // CHECK:STDOUT:   %Self: %I.type = bind_symbolic_name Self, 0 [symbolic = %Self (constants.%Self)]
-// CHECK:STDOUT:   %Self.as_type.loc14_16.1: type = facet_access_type %Self [symbolic = %Self.as_type.loc14_16.1 (constants.%Self.as_type)]
+// CHECK:STDOUT:   %Self.as_type.loc17_16.1: type = facet_access_type %Self [symbolic = %Self.as_type.loc17_16.1 (constants.%Self.as_type)]
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
-// CHECK:STDOUT:   %require_complete: <witness> = require_complete_type %Self.as_type.loc14_16.1 [symbolic = %require_complete (constants.%require_complete)]
+// CHECK:STDOUT:   %require_complete: <witness> = require_complete_type %Self.as_type.loc17_16.1 [symbolic = %require_complete (constants.%require_complete)]
 // CHECK:STDOUT:
-// CHECK:STDOUT:   fn(%self.param: @F.1.%Self.as_type.loc14_16.1 (%Self.as_type)) {
+// CHECK:STDOUT:   fn(%self.param: @F.1.%Self.as_type.loc17_16.1 (%Self.as_type)) {
 // CHECK:STDOUT:   !entry:
 // CHECK:STDOUT:     name_binding_decl {
 // CHECK:STDOUT:       %c.patt: %C = binding_pattern c
-// CHECK:STDOUT:       %.loc16_7.1: %C = var_pattern %c.patt
+// CHECK:STDOUT:       %.loc19_7.1: %C = var_pattern %c.patt
 // CHECK:STDOUT:     }
 // CHECK:STDOUT:     %c.var: ref %C = var c
-// CHECK:STDOUT:     %.loc16_19.1: %empty_struct_type = struct_literal ()
-// CHECK:STDOUT:     %.loc16_19.2: init %C = class_init (), %c.var [concrete = constants.%C.val]
-// CHECK:STDOUT:     %.loc16_7.2: init %C = converted %.loc16_19.1, %.loc16_19.2 [concrete = constants.%C.val]
-// CHECK:STDOUT:     assign %c.var, %.loc16_7.2
+// CHECK:STDOUT:     %.loc19_19.1: %empty_struct_type = struct_literal ()
+// CHECK:STDOUT:     %.loc19_19.2: init %C = class_init (), %c.var [concrete = constants.%C.val]
+// CHECK:STDOUT:     %.loc19_7.2: init %C = converted %.loc19_19.1, %.loc19_19.2 [concrete = constants.%C.val]
+// CHECK:STDOUT:     assign %c.var, %.loc19_7.2
 // CHECK:STDOUT:     %C.ref: type = name_ref C, file.%C.decl [concrete = constants.%C]
 // CHECK:STDOUT:     %c: ref %C = bind_name c, %c.var
 // CHECK:STDOUT:     %c.ref: ref %C = name_ref c, %c
@@ -135,8 +146,8 @@ class C {
 // CHECK:STDOUT:     %F.ref: %I.assoc_type = name_ref F, @I.%assoc0 [concrete = constants.%assoc0]
 // CHECK:STDOUT:     %impl.elem0: %.e5b = impl_witness_access constants.%I.impl_witness, element0 [concrete = constants.%F.eb2]
 // CHECK:STDOUT:     %bound_method: <bound method> = bound_method %c.ref, %impl.elem0
-// CHECK:STDOUT:     %.loc17: %C = bind_value %c.ref
-// CHECK:STDOUT:     %F.call: init %empty_tuple.type = call %bound_method(%.loc17)
+// CHECK:STDOUT:     %.loc20: %C = bind_value %c.ref
+// CHECK:STDOUT:     %F.call: init %empty_tuple.type = call %bound_method(%.loc20)
 // CHECK:STDOUT:     return
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
@@ -148,11 +159,17 @@ class C {
 // CHECK:STDOUT:
 // CHECK:STDOUT: specific @F.1(constants.%Self) {
 // CHECK:STDOUT:   %Self => constants.%Self
-// CHECK:STDOUT:   %Self.as_type.loc14_16.1 => constants.%Self.as_type
+// CHECK:STDOUT:   %Self.as_type.loc17_16.1 => constants.%Self.as_type
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: specific @F.1(constants.%I.facet) {
 // CHECK:STDOUT:   %Self => constants.%I.facet
-// CHECK:STDOUT:   %Self.as_type.loc14_16.1 => constants.%C
+// CHECK:STDOUT:   %Self.as_type.loc17_16.1 => constants.%C
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
diff --git a/toolchain/check/testdata/interface/no_prelude/fail_member_lookup.carbon b/toolchain/check/testdata/interface/min_prelude/fail_member_lookup.carbon
similarity index 97%
rename from toolchain/check/testdata/interface/no_prelude/fail_member_lookup.carbon
rename to toolchain/check/testdata/interface/min_prelude/fail_member_lookup.carbon
index d02434c82d0f..c936d82db276 100644
--- a/toolchain/check/testdata/interface/no_prelude/fail_member_lookup.carbon
+++ b/toolchain/check/testdata/interface/min_prelude/fail_member_lookup.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interface/no_prelude/fail_member_lookup.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interface/min_prelude/fail_member_lookup.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interface/no_prelude/fail_member_lookup.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interface/min_prelude/fail_member_lookup.carbon
 
 // --- core.carbon
 package Core;
@@ -184,6 +187,7 @@ fn G(U:! Different) -> U.(Interface.T);
 // CHECK:STDOUT: imports {
 // CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
 // CHECK:STDOUT:     .ImplicitAs = %Core.ImplicitAs
+// CHECK:STDOUT:     import Core//prelude
 // CHECK:STDOUT:     import Core//default
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.import_ref.5ab3ec.1: type = import_ref Core//default, loc3_22, loaded [symbolic = @ImplicitAs.%Dest (constants.%Dest)]
@@ -345,3 +349,9 @@ fn G(U:! Different) -> U.(Interface.T);
 // CHECK:STDOUT:   %U.patt.loc34_6.2 => constants.%U.patt
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/interface/no_prelude/generic_method.carbon b/toolchain/check/testdata/interface/min_prelude/generic_method.carbon
similarity index 98%
rename from toolchain/check/testdata/interface/no_prelude/generic_method.carbon
rename to toolchain/check/testdata/interface/min_prelude/generic_method.carbon
index 08083dc6950e..2aef686dee29 100644
--- a/toolchain/check/testdata/interface/no_prelude/generic_method.carbon
+++ b/toolchain/check/testdata/interface/min_prelude/generic_method.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interface/no_prelude/generic_method.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interface/min_prelude/generic_method.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interface/no_prelude/generic_method.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interface/min_prelude/generic_method.carbon
 
 // --- generic_method_fewer_params.carbon
 
@@ -146,8 +149,15 @@ fn CallIndirect() {
 // CHECK:STDOUT:   %tuple.type.9c8: type = tuple_type (%empty_struct_type, %empty_struct_type, %Z) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .A = %A.decl
 // CHECK:STDOUT:     .X = %X.decl
 // CHECK:STDOUT:     .Y = %Y.decl
@@ -156,6 +166,7 @@ fn CallIndirect() {
 // CHECK:STDOUT:     .CallGeneric = %CallGeneric.decl
 // CHECK:STDOUT:     .CallIndirect = %CallIndirect.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %A.decl: %A.type.495 = interface_decl @A [concrete = constants.%A.generic] {
 // CHECK:STDOUT:     %T.patt.loc5_13.1: type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc5_13.2 (constants.%T.patt.e01)]
 // CHECK:STDOUT:   } {
@@ -604,8 +615,15 @@ fn CallIndirect() {
 // CHECK:STDOUT:   %complete_type.4d1: <witness> = complete_type_witness %tuple.type.a46 [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .A = %A.decl
 // CHECK:STDOUT:     .X = %X.decl
 // CHECK:STDOUT:     .Y1 = %Y1.decl
@@ -615,6 +633,7 @@ fn CallIndirect() {
 // CHECK:STDOUT:     .CallGeneric = %CallGeneric.decl
 // CHECK:STDOUT:     .CallIndirect = %CallIndirect.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %A.decl: %A.type.495 = interface_decl @A [concrete = constants.%A.generic] {
 // CHECK:STDOUT:     %T.patt.loc5_13.1: type = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc5_13.2 (constants.%T.patt.e01)]
 // CHECK:STDOUT:   } {
@@ -1122,3 +1141,9 @@ fn CallIndirect() {
 // CHECK:STDOUT:   %tuple.type.loc6_38.2 => constants.%tuple.type.415
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/namespace/no_prelude/name_poisoning.carbon b/toolchain/check/testdata/namespace/min_prelude/name_poisoning.carbon
similarity index 95%
rename from toolchain/check/testdata/namespace/no_prelude/name_poisoning.carbon
rename to toolchain/check/testdata/namespace/min_prelude/name_poisoning.carbon
index 9f8bc4a06487..cbdc3b09959d 100644
--- a/toolchain/check/testdata/namespace/no_prelude/name_poisoning.carbon
+++ b/toolchain/check/testdata/namespace/min_prelude/name_poisoning.carbon
@@ -2,13 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
-// EXTRA-ARGS: --no-dump-sem-ir
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core --no-dump-sem-ir
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/namespace/no_prelude/name_poisoning.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/namespace/min_prelude/name_poisoning.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/namespace/no_prelude/name_poisoning.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/namespace/min_prelude/name_poisoning.carbon
 
 // --- no_poison.carbon
 
diff --git a/toolchain/check/testdata/patterns/no_prelude/underscore.carbon b/toolchain/check/testdata/patterns/min_prelude/underscore.carbon
similarity index 90%
rename from toolchain/check/testdata/patterns/no_prelude/underscore.carbon
rename to toolchain/check/testdata/patterns/min_prelude/underscore.carbon
index ccd3a1b66e45..bdc72cf68c77 100644
--- a/toolchain/check/testdata/patterns/no_prelude/underscore.carbon
+++ b/toolchain/check/testdata/patterns/min_prelude/underscore.carbon
@@ -7,9 +7,9 @@
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/patterns/no_prelude/underscore.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/patterns/min_prelude/underscore.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/patterns/no_prelude/underscore.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/patterns/min_prelude/underscore.carbon
 
 // --- basic.carbon
 
@@ -126,10 +126,19 @@ fn F() -> {} {
 // CHECK:STDOUT:   %F: %F.type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:     import Core//prelude/...
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   name_binding_decl {
 // CHECK:STDOUT:     %_.patt.loc4: %empty_struct_type = binding_pattern _
 // CHECK:STDOUT:   }
@@ -207,12 +216,21 @@ fn F() -> {} {
 // CHECK:STDOUT:   %empty_struct: %empty_struct_type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:     import Core//prelude/...
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:     .G = %G.decl
 // CHECK:STDOUT:     .H = %H.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {
 // CHECK:STDOUT:     %_.patt: %empty_struct_type = binding_pattern _
 // CHECK:STDOUT:     %_.param_patt: %empty_struct_type = value_param_pattern %_.patt, call_param0
@@ -269,11 +287,20 @@ fn F() -> {} {
 // CHECK:STDOUT:   %F.specific_fn: <specific function> = specific_function %F, @F(%empty_struct_type) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:     import Core//prelude/...
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:     .G = %G.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {
 // CHECK:STDOUT:     %_.patt.loc4_6.1: type = symbolic_binding_pattern _, 0 [symbolic = %_.patt.loc4_6.2 (constants.%_.patt)]
 // CHECK:STDOUT:   } {
@@ -330,11 +357,20 @@ fn F() -> {} {
 // CHECK:STDOUT:   %F.specific_fn: <specific function> = specific_function %F, @F(%empty_struct_type) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:     import Core//prelude/...
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:     .G = %G.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {
 // CHECK:STDOUT:     %_.patt.loc4_6.1: type = symbolic_binding_pattern _, 0 [symbolic = %_.patt.loc4_6.2 (constants.%_.patt)]
 // CHECK:STDOUT:   } {
@@ -381,11 +417,20 @@ fn F() -> {} {
 // CHECK:STDOUT:   %G: %G.type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:     import Core//prelude/...
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:     .G = %G.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {
 // CHECK:STDOUT:     %_.patt.loc4_6.1: type = symbolic_binding_pattern _, 0 [symbolic = %_.patt.loc4_6.2 (constants.%_.patt)]
 // CHECK:STDOUT:   } {
@@ -452,10 +497,19 @@ fn F() -> {} {
 // CHECK:STDOUT:   %assoc0: %I.assoc_type = assoc_entity element0, @I.%_ [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:     import Core//prelude/...
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .I = %I.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %I.decl: type = interface_decl @I [concrete = constants.%I.type] {} {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
diff --git a/toolchain/check/testdata/return/no_prelude/import_convert_function.carbon b/toolchain/check/testdata/return/min_prelude/import_convert_function.carbon
similarity index 99%
rename from toolchain/check/testdata/return/no_prelude/import_convert_function.carbon
rename to toolchain/check/testdata/return/min_prelude/import_convert_function.carbon
index 07f9f79fd785..899406b383ed 100644
--- a/toolchain/check/testdata/return/no_prelude/import_convert_function.carbon
+++ b/toolchain/check/testdata/return/min_prelude/import_convert_function.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/return/no_prelude/import_convert_function.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/return/min_prelude/import_convert_function.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/return/no_prelude/import_convert_function.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/return/min_prelude/import_convert_function.carbon
 
 // --- core.carbon
 
@@ -383,6 +386,7 @@ fn F0(n: i32) -> P.D {
 // CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
 // CHECK:STDOUT:     .Int = %Core.Int
 // CHECK:STDOUT:     .ImplicitAs = %Core.ImplicitAs
+// CHECK:STDOUT:     import Core//prelude
 // CHECK:STDOUT:     import Core//default
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.ImplicitAs: %ImplicitAs.type.cc7 = import_ref Core//default, ImplicitAs, loaded [concrete = constants.%ImplicitAs.generic]
@@ -1192,17 +1196,18 @@ fn F0(n: i32) -> P.D {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     .Int = %Core.Int
+// CHECK:STDOUT:     .ImplicitAs = %Core.ImplicitAs
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:     import Core//default
+// CHECK:STDOUT:   }
 // CHECK:STDOUT:   %P: <namespace> = namespace file.%P.import, [concrete] {
 // CHECK:STDOUT:     .D = %P.D
 // CHECK:STDOUT:     .C = %P.C
 // CHECK:STDOUT:     .Make = %P.Make
 // CHECK:STDOUT:     import P//library
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
-// CHECK:STDOUT:     .Int = %Core.Int
-// CHECK:STDOUT:     .ImplicitAs = %Core.ImplicitAs
-// CHECK:STDOUT:     import Core//default
-// CHECK:STDOUT:   }
 // CHECK:STDOUT:   %P.D: type = import_ref P//library, D, loaded [concrete = constants.%D]
 // CHECK:STDOUT:   %P.import_ref.7e5: <witness> = import_ref P//library, loc7_35, loaded [concrete = constants.%complete_type.682]
 // CHECK:STDOUT:   %P.import_ref.cab = import_ref P//library, inst48 [no loc], unloaded
@@ -1251,12 +1256,12 @@ fn F0(n: i32) -> P.D {
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
-// CHECK:STDOUT:     .P = imports.%P
 // CHECK:STDOUT:     .Core = imports.%Core
+// CHECK:STDOUT:     .P = imports.%P
 // CHECK:STDOUT:     .F0 = %F0.decl
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %P.import = import P
 // CHECK:STDOUT:   %Core.import = import Core
+// CHECK:STDOUT:   %P.import = import P
 // CHECK:STDOUT:   %F0.decl: %F0.type = fn_decl @F0 [concrete = constants.%F0] {
 // CHECK:STDOUT:     %n.patt: %i32.builtin = binding_pattern n
 // CHECK:STDOUT:     %n.param_patt: %i32.builtin = value_param_pattern %n.patt, call_param0
@@ -1725,3 +1730,9 @@ fn F0(n: i32) -> P.D {
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/tuple/no_prelude/tuple_pattern.carbon b/toolchain/check/testdata/tuple/min_prelude/tuple_pattern.carbon
similarity index 92%
rename from toolchain/check/testdata/tuple/no_prelude/tuple_pattern.carbon
rename to toolchain/check/testdata/tuple/min_prelude/tuple_pattern.carbon
index 401034e1f1cb..9172a433144d 100644
--- a/toolchain/check/testdata/tuple/no_prelude/tuple_pattern.carbon
+++ b/toolchain/check/testdata/tuple/min_prelude/tuple_pattern.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/tuple/no_prelude/tuple_pattern.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/tuple/min_prelude/tuple_pattern.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/tuple/no_prelude/tuple_pattern.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/tuple/min_prelude/tuple_pattern.carbon
 
 
 // --- basic.carbon
@@ -108,10 +111,18 @@ let (a: {}, b: {}) = ({}, {}, {});
 // CHECK:STDOUT:   %tuple: %tuple.type.b6b = tuple_value (%empty_struct, %empty_struct) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -209,13 +220,21 @@ let (a: {}, b: {}) = ({}, {}, {});
 // CHECK:STDOUT:   %H: %H.type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:     .G = %G.decl
 // CHECK:STDOUT:     .MakeTuple = %MakeTuple.decl
 // CHECK:STDOUT:     .H = %H.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
 // CHECK:STDOUT:   %G.decl: %G.type = fn_decl @G [concrete = constants.%G] {} {}
 // CHECK:STDOUT:   %MakeTuple.decl: %MakeTuple.type = fn_decl @MakeTuple [concrete = constants.%MakeTuple] {
@@ -394,10 +413,18 @@ let (a: {}, b: {}) = ({}, {}, {});
 // CHECK:STDOUT:   %empty_struct: %empty_struct_type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -447,11 +474,19 @@ let (a: {}, b: {}) = ({}, {}, {});
 // CHECK:STDOUT:   %empty_struct: %empty_struct_type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .x = %x
 // CHECK:STDOUT:     .y = %y
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   name_binding_decl {
 // CHECK:STDOUT:     %x.patt: %empty_struct_type = binding_pattern x
 // CHECK:STDOUT:     %y.patt: %empty_struct_type = binding_pattern y
@@ -488,10 +523,18 @@ let (a: {}, b: {}) = ({}, {}, {});
 // CHECK:STDOUT:   %Self: %I.type = bind_symbolic_name Self, 0 [symbolic]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .I = %I.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %I.decl: type = interface_decl @I [concrete = constants.%I.type] {} {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -500,8 +543,8 @@ let (a: {}, b: {}) = ({}, {}, {});
 // CHECK:STDOUT:
 // CHECK:STDOUT: !members:
 // CHECK:STDOUT:   .Self = %Self
-// CHECK:STDOUT:   .x = <unexpected>.inst23.loc9_8
-// CHECK:STDOUT:   .y = <unexpected>.inst27.loc9_15
+// CHECK:STDOUT:   .x = <unexpected>.inst25.loc9_8
+// CHECK:STDOUT:   .y = <unexpected>.inst29.loc9_15
 // CHECK:STDOUT:   has_error
 // CHECK:STDOUT:   witness = ()
 // CHECK:STDOUT: }
@@ -530,13 +573,21 @@ let (a: {}, b: {}) = ({}, {}, {});
 // CHECK:STDOUT:   %tuple.type.8d4: type = tuple_type (%empty_struct_type, %empty_struct_type, %empty_struct_type) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
-// CHECK:STDOUT:     .x = <unexpected>.inst19.loc8_6
-// CHECK:STDOUT:     .y = <unexpected>.inst23.loc8_13
-// CHECK:STDOUT:     .a = <unexpected>.inst33.loc14_6
-// CHECK:STDOUT:     .b = <unexpected>.inst37.loc14_13
+// CHECK:STDOUT:     .Core = imports.%Core
+// CHECK:STDOUT:     .x = <unexpected>.inst21.loc8_6
+// CHECK:STDOUT:     .y = <unexpected>.inst25.loc8_13
+// CHECK:STDOUT:     .a = <unexpected>.inst35.loc14_6
+// CHECK:STDOUT:     .b = <unexpected>.inst39.loc14_13
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   name_binding_decl {
 // CHECK:STDOUT:     %x.patt: %empty_struct_type = binding_pattern x
 // CHECK:STDOUT:     %y.patt: %empty_struct_type = binding_pattern y
@@ -560,3 +611,9 @@ let (a: {}, b: {}) = ({}, {}, {});
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/var/no_prelude/decl.carbon b/toolchain/check/testdata/var/min_prelude/decl.carbon
similarity index 54%
rename from toolchain/check/testdata/var/no_prelude/decl.carbon
rename to toolchain/check/testdata/var/min_prelude/decl.carbon
index bedae9eef3df..f2c983f574d4 100644
--- a/toolchain/check/testdata/var/no_prelude/decl.carbon
+++ b/toolchain/check/testdata/var/min_prelude/decl.carbon
@@ -2,17 +2,22 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/var/no_prelude/decl.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/var/min_prelude/decl.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/var/no_prelude/decl.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/var/min_prelude/decl.carbon
+
+// --- basic.carbon
 
 fn Main() {
   var x: ();
 }
 
-// CHECK:STDOUT: --- decl.carbon
+// CHECK:STDOUT: --- basic.carbon
 // CHECK:STDOUT:
 // CHECK:STDOUT: constants {
 // CHECK:STDOUT:   %Main.type: type = fn_type @Main [concrete]
@@ -20,10 +25,18 @@ fn Main() {
 // CHECK:STDOUT:   %Main: %Main.type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Main = %Main.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Main.decl: %Main.type = fn_decl @Main [concrete = constants.%Main] {} {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -31,14 +44,20 @@ fn Main() {
 // CHECK:STDOUT: !entry:
 // CHECK:STDOUT:   name_binding_decl {
 // CHECK:STDOUT:     %x.patt: %empty_tuple.type = binding_pattern x
-// CHECK:STDOUT:     %.loc12_3: %empty_tuple.type = var_pattern %x.patt
+// CHECK:STDOUT:     %.loc3_3: %empty_tuple.type = var_pattern %x.patt
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x.var: ref %empty_tuple.type = var x
-// CHECK:STDOUT:   %.loc12_11.1: type = splice_block %.loc12_11.3 [concrete = constants.%empty_tuple.type] {
-// CHECK:STDOUT:     %.loc12_11.2: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc12_11.3: type = converted %.loc12_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:   %.loc3_11.1: type = splice_block %.loc3_11.3 [concrete = constants.%empty_tuple.type] {
+// CHECK:STDOUT:     %.loc3_11.2: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc3_11.3: type = converted %.loc3_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x: ref %empty_tuple.type = bind_name x, %x.var
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/var/min_prelude/decl_with_init.carbon b/toolchain/check/testdata/var/min_prelude/decl_with_init.carbon
new file mode 100644
index 000000000000..6561d0ca5e01
--- /dev/null
+++ b/toolchain/check/testdata/var/min_prelude/decl_with_init.carbon
@@ -0,0 +1,68 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
+// AUTOUPDATE
+// TIP: To test this file alone, run:
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/var/min_prelude/decl_with_init.carbon
+// TIP: To dump output, run:
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/var/min_prelude/decl_with_init.carbon
+
+// --- basic.carbon
+
+fn Main() {
+  var x: () = ();
+}
+
+// CHECK:STDOUT: --- basic.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: constants {
+// CHECK:STDOUT:   %Main.type: type = fn_type @Main [concrete]
+// CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
+// CHECK:STDOUT:   %Main: %Main.type = struct_value () [concrete]
+// CHECK:STDOUT:   %empty_tuple: %empty_tuple.type = tuple_value () [concrete]
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
+// CHECK:STDOUT:     .Main = %Main.decl
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
+// CHECK:STDOUT:   %Main.decl: %Main.type = fn_decl @Main [concrete = constants.%Main] {} {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: fn @Main() {
+// CHECK:STDOUT: !entry:
+// CHECK:STDOUT:   name_binding_decl {
+// CHECK:STDOUT:     %x.patt: %empty_tuple.type = binding_pattern x
+// CHECK:STDOUT:     %.loc3_3.1: %empty_tuple.type = var_pattern %x.patt
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %x.var: ref %empty_tuple.type = var x
+// CHECK:STDOUT:   %.loc3_16.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:   %.loc3_16.2: init %empty_tuple.type = tuple_init () to %x.var [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   %.loc3_3.2: init %empty_tuple.type = converted %.loc3_16.1, %.loc3_16.2 [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   assign %x.var, %.loc3_3.2
+// CHECK:STDOUT:   %.loc3_11.1: type = splice_block %.loc3_11.3 [concrete = constants.%empty_tuple.type] {
+// CHECK:STDOUT:     %.loc3_11.2: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc3_11.3: type = converted %.loc3_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %x: ref %empty_tuple.type = bind_name x, %x.var
+// CHECK:STDOUT:   return
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/var/min_prelude/fail_duplicate_decl.carbon b/toolchain/check/testdata/var/min_prelude/fail_duplicate_decl.carbon
new file mode 100644
index 000000000000..716190995a7a
--- /dev/null
+++ b/toolchain/check/testdata/var/min_prelude/fail_duplicate_decl.carbon
@@ -0,0 +1,90 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
+// AUTOUPDATE
+// TIP: To test this file alone, run:
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/var/min_prelude/fail_duplicate_decl.carbon
+// TIP: To dump output, run:
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/var/min_prelude/fail_duplicate_decl.carbon
+
+// --- fail_basic.carbon
+
+fn Main() {
+  var x: () = ();
+  // CHECK:STDERR: fail_basic.carbon:[[@LINE+7]]:7: error: duplicate name `x` being declared in the same scope [NameDeclDuplicate]
+  // CHECK:STDERR:   var x: () = ();
+  // CHECK:STDERR:       ^
+  // CHECK:STDERR: fail_basic.carbon:[[@LINE-4]]:7: note: name is previously declared here [NameDeclPrevious]
+  // CHECK:STDERR:   var x: () = ();
+  // CHECK:STDERR:       ^
+  // CHECK:STDERR:
+  var x: () = ();
+}
+
+// CHECK:STDOUT: --- fail_basic.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: constants {
+// CHECK:STDOUT:   %Main.type: type = fn_type @Main [concrete]
+// CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
+// CHECK:STDOUT:   %Main: %Main.type = struct_value () [concrete]
+// CHECK:STDOUT:   %empty_tuple: %empty_tuple.type = tuple_value () [concrete]
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
+// CHECK:STDOUT:     .Main = %Main.decl
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
+// CHECK:STDOUT:   %Main.decl: %Main.type = fn_decl @Main [concrete = constants.%Main] {} {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: fn @Main() {
+// CHECK:STDOUT: !entry:
+// CHECK:STDOUT:   name_binding_decl {
+// CHECK:STDOUT:     %x.patt.loc3: %empty_tuple.type = binding_pattern x
+// CHECK:STDOUT:     %.loc3_3.1: %empty_tuple.type = var_pattern %x.patt.loc3
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %x.var.loc3: ref %empty_tuple.type = var x
+// CHECK:STDOUT:   %.loc3_16.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:   %.loc3_16.2: init %empty_tuple.type = tuple_init () to %x.var.loc3 [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   %.loc3_3.2: init %empty_tuple.type = converted %.loc3_16.1, %.loc3_16.2 [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   assign %x.var.loc3, %.loc3_3.2
+// CHECK:STDOUT:   %.loc3_11.1: type = splice_block %.loc3_11.3 [concrete = constants.%empty_tuple.type] {
+// CHECK:STDOUT:     %.loc3_11.2: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc3_11.3: type = converted %.loc3_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %x.loc3: ref %empty_tuple.type = bind_name x, %x.var.loc3
+// CHECK:STDOUT:   name_binding_decl {
+// CHECK:STDOUT:     %x.patt.loc11: %empty_tuple.type = binding_pattern x
+// CHECK:STDOUT:     %.loc11_3.1: %empty_tuple.type = var_pattern %x.patt.loc11
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %x.var.loc11: ref %empty_tuple.type = var x
+// CHECK:STDOUT:   %.loc11_16.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:   %.loc11_16.2: init %empty_tuple.type = tuple_init () to %x.var.loc11 [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   %.loc11_3.2: init %empty_tuple.type = converted %.loc11_16.1, %.loc11_16.2 [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   assign %x.var.loc11, %.loc11_3.2
+// CHECK:STDOUT:   %.loc11_11.1: type = splice_block %.loc11_11.3 [concrete = constants.%empty_tuple.type] {
+// CHECK:STDOUT:     %.loc11_11.2: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc11_11.3: type = converted %.loc11_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %x.loc11: ref %empty_tuple.type = bind_name x, %x.var.loc11
+// CHECK:STDOUT:   return
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/var/no_prelude/fail_init_with_self.carbon b/toolchain/check/testdata/var/min_prelude/fail_init_with_self.carbon
similarity index 54%
rename from toolchain/check/testdata/var/no_prelude/fail_init_with_self.carbon
rename to toolchain/check/testdata/var/min_prelude/fail_init_with_self.carbon
index e136091d7055..463d9cbad7f9 100644
--- a/toolchain/check/testdata/var/no_prelude/fail_init_with_self.carbon
+++ b/toolchain/check/testdata/var/min_prelude/fail_init_with_self.carbon
@@ -2,21 +2,26 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/var/no_prelude/fail_init_with_self.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/var/min_prelude/fail_init_with_self.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/var/no_prelude/fail_init_with_self.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/var/min_prelude/fail_init_with_self.carbon
+
+// --- fail_basic.carbon
 
 fn Main() {
-  // CHECK:STDERR: fail_init_with_self.carbon:[[@LINE+4]]:15: error: `x` used before initialization [UsedBeforeInitialization]
+  // CHECK:STDERR: fail_basic.carbon:[[@LINE+4]]:15: error: `x` used before initialization [UsedBeforeInitialization]
   // CHECK:STDERR:   var x: () = x;
   // CHECK:STDERR:               ^
   // CHECK:STDERR:
   var x: () = x;
 }
 
-// CHECK:STDOUT: --- fail_init_with_self.carbon
+// CHECK:STDOUT: --- fail_basic.carbon
 // CHECK:STDOUT:
 // CHECK:STDOUT: constants {
 // CHECK:STDOUT:   %Main.type: type = fn_type @Main [concrete]
@@ -24,10 +29,18 @@ fn Main() {
 // CHECK:STDOUT:   %Main: %Main.type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Main = %Main.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Main.decl: %Main.type = fn_decl @Main [concrete = constants.%Main] {} {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -35,16 +48,22 @@ fn Main() {
 // CHECK:STDOUT: !entry:
 // CHECK:STDOUT:   name_binding_decl {
 // CHECK:STDOUT:     %x.patt: %empty_tuple.type = binding_pattern x
-// CHECK:STDOUT:     %.loc16_3: %empty_tuple.type = var_pattern %x.patt
+// CHECK:STDOUT:     %.loc7_3: %empty_tuple.type = var_pattern %x.patt
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x.var: ref %empty_tuple.type = var x
 // CHECK:STDOUT:   %x.ref: <error> = name_ref x, <error> [concrete = <error>]
 // CHECK:STDOUT:   assign %x.var, <error>
-// CHECK:STDOUT:   %.loc16_11.1: type = splice_block %.loc16_11.3 [concrete = constants.%empty_tuple.type] {
-// CHECK:STDOUT:     %.loc16_11.2: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc16_11.3: type = converted %.loc16_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:   %.loc7_11.1: type = splice_block %.loc7_11.3 [concrete = constants.%empty_tuple.type] {
+// CHECK:STDOUT:     %.loc7_11.2: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc7_11.3: type = converted %.loc7_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x: ref %empty_tuple.type = bind_name x, %x.var
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/var/no_prelude/fail_lookup_outside_scope.carbon b/toolchain/check/testdata/var/min_prelude/fail_lookup_outside_scope.carbon
similarity index 58%
rename from toolchain/check/testdata/var/no_prelude/fail_lookup_outside_scope.carbon
rename to toolchain/check/testdata/var/min_prelude/fail_lookup_outside_scope.carbon
index c32a4bb68f4c..0d9e37af3e19 100644
--- a/toolchain/check/testdata/var/no_prelude/fail_lookup_outside_scope.carbon
+++ b/toolchain/check/testdata/var/min_prelude/fail_lookup_outside_scope.carbon
@@ -2,23 +2,28 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/var/no_prelude/fail_lookup_outside_scope.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/var/min_prelude/fail_lookup_outside_scope.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/var/no_prelude/fail_lookup_outside_scope.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/var/min_prelude/fail_lookup_outside_scope.carbon
+
+// --- fail_basic.carbon
 
 fn Main() {
   var x: ();
 }
 
-// CHECK:STDERR: fail_lookup_outside_scope.carbon:[[@LINE+4]]:13: error: name `x` not found [NameNotFound]
+// CHECK:STDERR: fail_basic.carbon:[[@LINE+4]]:13: error: name `x` not found [NameNotFound]
 // CHECK:STDERR: var y: () = x;
 // CHECK:STDERR:             ^
 // CHECK:STDERR:
 var y: () = x;
 
-// CHECK:STDOUT: --- fail_lookup_outside_scope.carbon
+// CHECK:STDOUT: --- fail_basic.carbon
 // CHECK:STDOUT:
 // CHECK:STDOUT: constants {
 // CHECK:STDOUT:   %Main.type: type = fn_type @Main [concrete]
@@ -26,21 +31,29 @@ var y: () = x;
 // CHECK:STDOUT:   %Main: %Main.type = struct_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Main = %Main.decl
 // CHECK:STDOUT:     .y = %y
 // CHECK:STDOUT:     .x = <poisoned>
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Main.decl: %Main.type = fn_decl @Main [concrete = constants.%Main] {} {}
 // CHECK:STDOUT:   name_binding_decl {
 // CHECK:STDOUT:     %y.patt: %empty_tuple.type = binding_pattern y
-// CHECK:STDOUT:     %.loc19_1: %empty_tuple.type = var_pattern %y.patt
+// CHECK:STDOUT:     %.loc10_1: %empty_tuple.type = var_pattern %y.patt
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %y.var: ref %empty_tuple.type = var y
-// CHECK:STDOUT:   %.loc19_9.1: type = splice_block %.loc19_9.3 [concrete = constants.%empty_tuple.type] {
-// CHECK:STDOUT:     %.loc19_9.2: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc19_9.3: type = converted %.loc19_9.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:   %.loc10_9.1: type = splice_block %.loc10_9.3 [concrete = constants.%empty_tuple.type] {
+// CHECK:STDOUT:     %.loc10_9.2: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc10_9.3: type = converted %.loc10_9.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %y: ref %empty_tuple.type = bind_name y, %y.var
 // CHECK:STDOUT: }
@@ -49,12 +62,12 @@ var y: () = x;
 // CHECK:STDOUT: !entry:
 // CHECK:STDOUT:   name_binding_decl {
 // CHECK:STDOUT:     %x.patt: %empty_tuple.type = binding_pattern x
-// CHECK:STDOUT:     %.loc12_3: %empty_tuple.type = var_pattern %x.patt
+// CHECK:STDOUT:     %.loc3_3: %empty_tuple.type = var_pattern %x.patt
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x.var: ref %empty_tuple.type = var x
-// CHECK:STDOUT:   %.loc12_11.1: type = splice_block %.loc12_11.3 [concrete = constants.%empty_tuple.type] {
-// CHECK:STDOUT:     %.loc12_11.2: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc12_11.3: type = converted %.loc12_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:   %.loc3_11.1: type = splice_block %.loc3_11.3 [concrete = constants.%empty_tuple.type] {
+// CHECK:STDOUT:     %.loc3_11.2: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc3_11.3: type = converted %.loc3_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x: ref %empty_tuple.type = bind_name x, %x.var
 // CHECK:STDOUT:   return
@@ -67,3 +80,9 @@ var y: () = x;
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/var/min_prelude/global_lookup_in_scope.carbon b/toolchain/check/testdata/var/min_prelude/global_lookup_in_scope.carbon
new file mode 100644
index 000000000000..25a3dbc3d90c
--- /dev/null
+++ b/toolchain/check/testdata/var/min_prelude/global_lookup_in_scope.carbon
@@ -0,0 +1,102 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
+// AUTOUPDATE
+// TIP: To test this file alone, run:
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/var/min_prelude/global_lookup_in_scope.carbon
+// TIP: To dump output, run:
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/var/min_prelude/global_lookup_in_scope.carbon
+
+// --- basic.carbon
+
+var x: {.v: ()} = {.v = ()};
+
+fn Main() {
+  var y: {.v: ()} = x;
+}
+
+// CHECK:STDOUT: --- basic.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: constants {
+// CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
+// CHECK:STDOUT:   %struct_type.v: type = struct_type {.v: %empty_tuple.type} [concrete]
+// CHECK:STDOUT:   %empty_tuple: %empty_tuple.type = tuple_value () [concrete]
+// CHECK:STDOUT:   %struct: %struct_type.v = struct_value (%empty_tuple) [concrete]
+// CHECK:STDOUT:   %Main.type: type = fn_type @Main [concrete]
+// CHECK:STDOUT:   %Main: %Main.type = struct_value () [concrete]
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
+// CHECK:STDOUT:     .x = %x
+// CHECK:STDOUT:     .Main = %Main.decl
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
+// CHECK:STDOUT:   name_binding_decl {
+// CHECK:STDOUT:     %x.patt: %struct_type.v = binding_pattern x
+// CHECK:STDOUT:     %.loc2_1: %struct_type.v = var_pattern %x.patt
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %x.var: ref %struct_type.v = var x
+// CHECK:STDOUT:   %.loc2_15: type = splice_block %struct_type.v [concrete = constants.%struct_type.v] {
+// CHECK:STDOUT:     %.loc2_14.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc2_14.2: type = converted %.loc2_14.1, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:     %struct_type.v: type = struct_type {.v: %empty_tuple.type} [concrete = constants.%struct_type.v]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %x: ref %struct_type.v = bind_name x, %x.var
+// CHECK:STDOUT:   %Main.decl: %Main.type = fn_decl @Main [concrete = constants.%Main] {} {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: fn @Main() {
+// CHECK:STDOUT: !entry:
+// CHECK:STDOUT:   name_binding_decl {
+// CHECK:STDOUT:     %y.patt: %struct_type.v = binding_pattern y
+// CHECK:STDOUT:     %.loc5_3.1: %struct_type.v = var_pattern %y.patt
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %y.var: ref %struct_type.v = var y
+// CHECK:STDOUT:   %x.ref: ref %struct_type.v = name_ref x, file.%x
+// CHECK:STDOUT:   %.loc5_21.1: ref %empty_tuple.type = struct_access %x.ref, element0
+// CHECK:STDOUT:   %.loc5_21.2: ref %empty_tuple.type = struct_access %y.var, element0
+// CHECK:STDOUT:   %.loc5_21.3: init %empty_tuple.type = tuple_init () to %.loc5_21.2 [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   %.loc5_21.4: init %empty_tuple.type = converted %.loc5_21.1, %.loc5_21.3 [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   %.loc5_21.5: init %struct_type.v = struct_init (%.loc5_21.4) to %y.var [concrete = constants.%struct]
+// CHECK:STDOUT:   %.loc5_3.2: init %struct_type.v = converted %x.ref, %.loc5_21.5 [concrete = constants.%struct]
+// CHECK:STDOUT:   assign %y.var, %.loc5_3.2
+// CHECK:STDOUT:   %.loc5_17: type = splice_block %struct_type.v [concrete = constants.%struct_type.v] {
+// CHECK:STDOUT:     %.loc5_16.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc5_16.2: type = converted %.loc5_16.1, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:     %struct_type.v: type = struct_type {.v: %empty_tuple.type} [concrete = constants.%struct_type.v]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %y: ref %struct_type.v = bind_name y, %y.var
+// CHECK:STDOUT:   return
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: fn @__global_init() {
+// CHECK:STDOUT: !entry:
+// CHECK:STDOUT:   %.loc2_26.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:   %.loc2_27.1: %struct_type.v = struct_literal (%.loc2_26.1)
+// CHECK:STDOUT:   %.loc2_27.2: ref %empty_tuple.type = struct_access file.%x.var, element0
+// CHECK:STDOUT:   %.loc2_26.2: init %empty_tuple.type = tuple_init () to %.loc2_27.2 [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   %.loc2_27.3: init %empty_tuple.type = converted %.loc2_26.1, %.loc2_26.2 [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   %.loc2_27.4: init %struct_type.v = struct_init (%.loc2_27.3) to file.%x.var [concrete = constants.%struct]
+// CHECK:STDOUT:   %.loc2_1: init %struct_type.v = converted %.loc2_27.1, %.loc2_27.4 [concrete = constants.%struct]
+// CHECK:STDOUT:   assign file.%x.var, %.loc2_1
+// CHECK:STDOUT:   return
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/var/no_prelude/lookup.carbon b/toolchain/check/testdata/var/min_prelude/lookup.carbon
similarity index 58%
rename from toolchain/check/testdata/var/no_prelude/lookup.carbon
rename to toolchain/check/testdata/var/min_prelude/lookup.carbon
index cd20578717aa..8c83b6385591 100644
--- a/toolchain/check/testdata/var/no_prelude/lookup.carbon
+++ b/toolchain/check/testdata/var/min_prelude/lookup.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/var/no_prelude/lookup.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/var/min_prelude/lookup.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/var/no_prelude/lookup.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/var/min_prelude/lookup.carbon
 
 fn Main() {
   var x: () = ();
@@ -22,10 +25,18 @@ fn Main() {
 // CHECK:STDOUT:   %empty_tuple: %empty_tuple.type = tuple_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .Main = %Main.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Main.decl: %Main.type = fn_decl @Main [concrete = constants.%Main] {} {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -33,19 +44,25 @@ fn Main() {
 // CHECK:STDOUT: !entry:
 // CHECK:STDOUT:   name_binding_decl {
 // CHECK:STDOUT:     %x.patt: %empty_tuple.type = binding_pattern x
-// CHECK:STDOUT:     %.loc12_3.1: %empty_tuple.type = var_pattern %x.patt
+// CHECK:STDOUT:     %.loc15_3.1: %empty_tuple.type = var_pattern %x.patt
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x.var: ref %empty_tuple.type = var x
-// CHECK:STDOUT:   %.loc12_16.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc12_16.2: init %empty_tuple.type = tuple_init () to %x.var [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   %.loc12_3.2: init %empty_tuple.type = converted %.loc12_16.1, %.loc12_16.2 [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   assign %x.var, %.loc12_3.2
-// CHECK:STDOUT:   %.loc12_11.1: type = splice_block %.loc12_11.3 [concrete = constants.%empty_tuple.type] {
-// CHECK:STDOUT:     %.loc12_11.2: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc12_11.3: type = converted %.loc12_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:   %.loc15_16.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:   %.loc15_16.2: init %empty_tuple.type = tuple_init () to %x.var [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   %.loc15_3.2: init %empty_tuple.type = converted %.loc15_16.1, %.loc15_16.2 [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   assign %x.var, %.loc15_3.2
+// CHECK:STDOUT:   %.loc15_11.1: type = splice_block %.loc15_11.3 [concrete = constants.%empty_tuple.type] {
+// CHECK:STDOUT:     %.loc15_11.2: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc15_11.3: type = converted %.loc15_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x: ref %empty_tuple.type = bind_name x, %x.var
 // CHECK:STDOUT:   %x.ref: ref %empty_tuple.type = name_ref x, %x
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/var/min_prelude/shadowing.carbon b/toolchain/check/testdata/var/min_prelude/shadowing.carbon
new file mode 100644
index 000000000000..6fdbc19f886b
--- /dev/null
+++ b/toolchain/check/testdata/var/min_prelude/shadowing.carbon
@@ -0,0 +1,127 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
+// AUTOUPDATE
+// TIP: To test this file alone, run:
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/var/min_prelude/shadowing.carbon
+// TIP: To dump output, run:
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/var/min_prelude/shadowing.carbon
+
+// --- basics.carbon
+
+namespace NS;
+
+fn Main() {
+  var NS: () = ();
+  NS = ();
+
+  var x: () = ();
+  if (true) {
+    var x: () = ();
+
+    // TODO: We should reject this use of the shadowed variable `x`.
+    x = ();
+  }
+}
+
+// CHECK:STDOUT: --- basics.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: constants {
+// CHECK:STDOUT:   %Main.type: type = fn_type @Main [concrete]
+// CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
+// CHECK:STDOUT:   %Main: %Main.type = struct_value () [concrete]
+// CHECK:STDOUT:   %empty_tuple: %empty_tuple.type = tuple_value () [concrete]
+// CHECK:STDOUT:   %true: bool = bool_literal true [concrete]
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
+// CHECK:STDOUT:     .NS = %NS
+// CHECK:STDOUT:     .Main = %Main.decl
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
+// CHECK:STDOUT:   %NS: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT:   %Main.decl: %Main.type = fn_decl @Main [concrete = constants.%Main] {} {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: fn @Main() {
+// CHECK:STDOUT: !entry:
+// CHECK:STDOUT:   name_binding_decl {
+// CHECK:STDOUT:     %NS.patt: %empty_tuple.type = binding_pattern NS
+// CHECK:STDOUT:     %.loc5_3.1: %empty_tuple.type = var_pattern %NS.patt
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %NS.var: ref %empty_tuple.type = var NS
+// CHECK:STDOUT:   %.loc5_17.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:   %.loc5_17.2: init %empty_tuple.type = tuple_init () to %NS.var [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   %.loc5_3.2: init %empty_tuple.type = converted %.loc5_17.1, %.loc5_17.2 [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   assign %NS.var, %.loc5_3.2
+// CHECK:STDOUT:   %.loc5_12.1: type = splice_block %.loc5_12.3 [concrete = constants.%empty_tuple.type] {
+// CHECK:STDOUT:     %.loc5_12.2: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc5_12.3: type = converted %.loc5_12.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %NS: ref %empty_tuple.type = bind_name NS, %NS.var
+// CHECK:STDOUT:   %NS.ref: ref %empty_tuple.type = name_ref NS, %NS
+// CHECK:STDOUT:   %.loc6_9.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:   %.loc6_9.2: init %empty_tuple.type = tuple_init () to %NS.ref [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   %.loc6_6: init %empty_tuple.type = converted %.loc6_9.1, %.loc6_9.2 [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   assign %NS.ref, %.loc6_6
+// CHECK:STDOUT:   name_binding_decl {
+// CHECK:STDOUT:     %x.patt.loc8: %empty_tuple.type = binding_pattern x
+// CHECK:STDOUT:     %.loc8_3.1: %empty_tuple.type = var_pattern %x.patt.loc8
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %x.var.loc8: ref %empty_tuple.type = var x
+// CHECK:STDOUT:   %.loc8_16.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:   %.loc8_16.2: init %empty_tuple.type = tuple_init () to %x.var.loc8 [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   %.loc8_3.2: init %empty_tuple.type = converted %.loc8_16.1, %.loc8_16.2 [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   assign %x.var.loc8, %.loc8_3.2
+// CHECK:STDOUT:   %.loc8_11.1: type = splice_block %.loc8_11.3 [concrete = constants.%empty_tuple.type] {
+// CHECK:STDOUT:     %.loc8_11.2: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc8_11.3: type = converted %.loc8_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %x.loc8: ref %empty_tuple.type = bind_name x, %x.var.loc8
+// CHECK:STDOUT:   %true: bool = bool_literal true [concrete = constants.%true]
+// CHECK:STDOUT:   if %true br !if.then else br !if.else
+// CHECK:STDOUT:
+// CHECK:STDOUT: !if.then:
+// CHECK:STDOUT:   name_binding_decl {
+// CHECK:STDOUT:     %x.patt.loc10: %empty_tuple.type = binding_pattern x
+// CHECK:STDOUT:     %.loc10_5.1: %empty_tuple.type = var_pattern %x.patt.loc10
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %x.var.loc10: ref %empty_tuple.type = var x
+// CHECK:STDOUT:   %.loc10_18.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:   %.loc10_18.2: init %empty_tuple.type = tuple_init () to %x.var.loc10 [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   %.loc10_5.2: init %empty_tuple.type = converted %.loc10_18.1, %.loc10_18.2 [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   assign %x.var.loc10, %.loc10_5.2
+// CHECK:STDOUT:   %.loc10_13.1: type = splice_block %.loc10_13.3 [concrete = constants.%empty_tuple.type] {
+// CHECK:STDOUT:     %.loc10_13.2: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:     %.loc10_13.3: type = converted %.loc10_13.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %x.loc10: ref %empty_tuple.type = bind_name x, %x.var.loc10
+// CHECK:STDOUT:   %x.ref: ref %empty_tuple.type = name_ref x, %x.loc10
+// CHECK:STDOUT:   %.loc13_10.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:   %.loc13_10.2: init %empty_tuple.type = tuple_init () to %x.ref [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   %.loc13_7: init %empty_tuple.type = converted %.loc13_10.1, %.loc13_10.2 [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   assign %x.ref, %.loc13_7
+// CHECK:STDOUT:   br !if.else
+// CHECK:STDOUT:
+// CHECK:STDOUT: !if.else:
+// CHECK:STDOUT:   return
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/var/no_prelude/var_pattern.carbon b/toolchain/check/testdata/var/min_prelude/var_pattern.carbon
similarity index 90%
rename from toolchain/check/testdata/var/no_prelude/var_pattern.carbon
rename to toolchain/check/testdata/var/min_prelude/var_pattern.carbon
index 192366170169..189c7c12d6d6 100644
--- a/toolchain/check/testdata/var/no_prelude/var_pattern.carbon
+++ b/toolchain/check/testdata/var/min_prelude/var_pattern.carbon
@@ -2,11 +2,14 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// EXTRA-ARGS: --custom-core
+//
 // AUTOUPDATE
 // TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/var/no_prelude/var_pattern.carbon
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/var/min_prelude/var_pattern.carbon
 // TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/var/no_prelude/var_pattern.carbon
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/var/min_prelude/var_pattern.carbon
 
 // --- basic.carbon
 
@@ -101,10 +104,18 @@ class C {
 // CHECK:STDOUT:   %empty_tuple: %empty_tuple.type = tuple_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -137,10 +148,18 @@ class C {
 // CHECK:STDOUT:   %empty_tuple: %empty_tuple.type = tuple_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -185,11 +204,19 @@ class C {
 // CHECK:STDOUT:   %empty_tuple: %empty_tuple.type = tuple_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:     .G = %G.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {
 // CHECK:STDOUT:     %x.patt: %empty_tuple.type = binding_pattern x
 // CHECK:STDOUT:     %x.param_patt: %empty_tuple.type = value_param_pattern %x.patt, call_param0
@@ -256,10 +283,18 @@ class C {
 // CHECK:STDOUT:   %tuple: %tuple.type.bcd = tuple_value (%empty_tuple, %empty_tuple) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .F = %F.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -343,10 +378,18 @@ class C {
 // CHECK:STDOUT:   %complete_type: <witness> = complete_type_witness %empty_struct_type [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Core: <namespace> = namespace file.%Core.import, [concrete] {
+// CHECK:STDOUT:     import Core//prelude
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
+// CHECK:STDOUT:     .Core = imports.%Core
 // CHECK:STDOUT:     .C = %C.decl
 // CHECK:STDOUT:   }
+// CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %C.decl: type = class_decl @C [concrete = constants.%C] {} {}
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -371,3 +414,9 @@ class C {
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @F(%self.param: %C);
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- include_files/destroy.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {}
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/var/no_prelude/decl_with_init.carbon b/toolchain/check/testdata/var/no_prelude/decl_with_init.carbon
deleted file mode 100644
index f80026df06b0..000000000000
--- a/toolchain/check/testdata/var/no_prelude/decl_with_init.carbon
+++ /dev/null
@@ -1,49 +0,0 @@
-// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
-// Exceptions. See /LICENSE for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-// AUTOUPDATE
-// TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/var/no_prelude/decl_with_init.carbon
-// TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/var/no_prelude/decl_with_init.carbon
-
-fn Main() {
-  var x: () = ();
-}
-
-// CHECK:STDOUT: --- decl_with_init.carbon
-// CHECK:STDOUT:
-// CHECK:STDOUT: constants {
-// CHECK:STDOUT:   %Main.type: type = fn_type @Main [concrete]
-// CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
-// CHECK:STDOUT:   %Main: %Main.type = struct_value () [concrete]
-// CHECK:STDOUT:   %empty_tuple: %empty_tuple.type = tuple_value () [concrete]
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: file {
-// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
-// CHECK:STDOUT:     .Main = %Main.decl
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %Main.decl: %Main.type = fn_decl @Main [concrete = constants.%Main] {} {}
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: fn @Main() {
-// CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   name_binding_decl {
-// CHECK:STDOUT:     %x.patt: %empty_tuple.type = binding_pattern x
-// CHECK:STDOUT:     %.loc12_3.1: %empty_tuple.type = var_pattern %x.patt
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %x.var: ref %empty_tuple.type = var x
-// CHECK:STDOUT:   %.loc12_16.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc12_16.2: init %empty_tuple.type = tuple_init () to %x.var [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   %.loc12_3.2: init %empty_tuple.type = converted %.loc12_16.1, %.loc12_16.2 [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   assign %x.var, %.loc12_3.2
-// CHECK:STDOUT:   %.loc12_11.1: type = splice_block %.loc12_11.3 [concrete = constants.%empty_tuple.type] {
-// CHECK:STDOUT:     %.loc12_11.2: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc12_11.3: type = converted %.loc12_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %x: ref %empty_tuple.type = bind_name x, %x.var
-// CHECK:STDOUT:   return
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/var/no_prelude/fail_duplicate_decl.carbon b/toolchain/check/testdata/var/no_prelude/fail_duplicate_decl.carbon
deleted file mode 100644
index 59ec5f478d7d..000000000000
--- a/toolchain/check/testdata/var/no_prelude/fail_duplicate_decl.carbon
+++ /dev/null
@@ -1,72 +0,0 @@
-// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
-// Exceptions. See /LICENSE for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-// AUTOUPDATE
-// TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/var/no_prelude/fail_duplicate_decl.carbon
-// TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/var/no_prelude/fail_duplicate_decl.carbon
-
-
-fn Main() {
-  var x: () = ();
-  // CHECK:STDERR: fail_duplicate_decl.carbon:[[@LINE+7]]:7: error: duplicate name `x` being declared in the same scope [NameDeclDuplicate]
-  // CHECK:STDERR:   var x: () = ();
-  // CHECK:STDERR:       ^
-  // CHECK:STDERR: fail_duplicate_decl.carbon:[[@LINE-4]]:7: note: name is previously declared here [NameDeclPrevious]
-  // CHECK:STDERR:   var x: () = ();
-  // CHECK:STDERR:       ^
-  // CHECK:STDERR:
-  var x: () = ();
-}
-
-// CHECK:STDOUT: --- fail_duplicate_decl.carbon
-// CHECK:STDOUT:
-// CHECK:STDOUT: constants {
-// CHECK:STDOUT:   %Main.type: type = fn_type @Main [concrete]
-// CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
-// CHECK:STDOUT:   %Main: %Main.type = struct_value () [concrete]
-// CHECK:STDOUT:   %empty_tuple: %empty_tuple.type = tuple_value () [concrete]
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: file {
-// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
-// CHECK:STDOUT:     .Main = %Main.decl
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %Main.decl: %Main.type = fn_decl @Main [concrete = constants.%Main] {} {}
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: fn @Main() {
-// CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   name_binding_decl {
-// CHECK:STDOUT:     %x.patt.loc13: %empty_tuple.type = binding_pattern x
-// CHECK:STDOUT:     %.loc13_3.1: %empty_tuple.type = var_pattern %x.patt.loc13
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %x.var.loc13: ref %empty_tuple.type = var x
-// CHECK:STDOUT:   %.loc13_16.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc13_16.2: init %empty_tuple.type = tuple_init () to %x.var.loc13 [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   %.loc13_3.2: init %empty_tuple.type = converted %.loc13_16.1, %.loc13_16.2 [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   assign %x.var.loc13, %.loc13_3.2
-// CHECK:STDOUT:   %.loc13_11.1: type = splice_block %.loc13_11.3 [concrete = constants.%empty_tuple.type] {
-// CHECK:STDOUT:     %.loc13_11.2: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc13_11.3: type = converted %.loc13_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %x.loc13: ref %empty_tuple.type = bind_name x, %x.var.loc13
-// CHECK:STDOUT:   name_binding_decl {
-// CHECK:STDOUT:     %x.patt.loc21: %empty_tuple.type = binding_pattern x
-// CHECK:STDOUT:     %.loc21_3.1: %empty_tuple.type = var_pattern %x.patt.loc21
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %x.var.loc21: ref %empty_tuple.type = var x
-// CHECK:STDOUT:   %.loc21_16.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc21_16.2: init %empty_tuple.type = tuple_init () to %x.var.loc21 [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   %.loc21_3.2: init %empty_tuple.type = converted %.loc21_16.1, %.loc21_16.2 [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   assign %x.var.loc21, %.loc21_3.2
-// CHECK:STDOUT:   %.loc21_11.1: type = splice_block %.loc21_11.3 [concrete = constants.%empty_tuple.type] {
-// CHECK:STDOUT:     %.loc21_11.2: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc21_11.3: type = converted %.loc21_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %x.loc21: ref %empty_tuple.type = bind_name x, %x.var.loc21
-// CHECK:STDOUT:   return
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/var/no_prelude/fail_init_type_mismatch.carbon b/toolchain/check/testdata/var/no_prelude/fail_init_type_mismatch.carbon
index 4e07a2f19365..856f79fd93e6 100644
--- a/toolchain/check/testdata/var/no_prelude/fail_init_type_mismatch.carbon
+++ b/toolchain/check/testdata/var/no_prelude/fail_init_type_mismatch.carbon
@@ -8,48 +8,43 @@
 // TIP: To dump output, run:
 // TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/var/no_prelude/fail_init_type_mismatch.carbon
 
-fn Main() {
-  // CHECK:STDERR: fail_init_type_mismatch.carbon:[[@LINE+4]]:3: error: `Core.ImplicitAs` implicitly referenced here, but package `Core` not found [CoreNotFound]
-  // CHECK:STDERR:   var x: {} = ();
-  // CHECK:STDERR:   ^~~~~~~~~
-  // CHECK:STDERR:
-  var x: {} = ();
-}
+// CHECK:STDERR: fail_init_type_mismatch.carbon:[[@LINE+4]]:1: error: `Core.ImplicitAs` implicitly referenced here, but package `Core` not found [CoreNotFound]
+// CHECK:STDERR: var x: {} = ();
+// CHECK:STDERR: ^~~~~~~~~
+// CHECK:STDERR:
+var x: {} = ();
 
 // CHECK:STDOUT: --- fail_init_type_mismatch.carbon
 // CHECK:STDOUT:
 // CHECK:STDOUT: constants {
-// CHECK:STDOUT:   %Main.type: type = fn_type @Main [concrete]
-// CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
-// CHECK:STDOUT:   %Main: %Main.type = struct_value () [concrete]
 // CHECK:STDOUT:   %empty_struct_type: type = struct_type {} [concrete]
+// CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
 // CHECK:STDOUT:   %empty_tuple: %empty_tuple.type = tuple_value () [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
 // CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
-// CHECK:STDOUT:     .Main = %Main.decl
+// CHECK:STDOUT:     .x = %x
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %Main.decl: %Main.type = fn_decl @Main [concrete = constants.%Main] {} {}
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: fn @Main() {
-// CHECK:STDOUT: !entry:
 // CHECK:STDOUT:   name_binding_decl {
 // CHECK:STDOUT:     %x.patt: %empty_struct_type = binding_pattern x
-// CHECK:STDOUT:     %.loc16_3.1: %empty_struct_type = var_pattern %x.patt
+// CHECK:STDOUT:     %.loc15_1: %empty_struct_type = var_pattern %x.patt
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x.var: ref %empty_struct_type = var x
-// CHECK:STDOUT:   %.loc16_16.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %empty_tuple: %empty_tuple.type = tuple_value () [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   %.loc16_16.2: %empty_tuple.type = converted %.loc16_16.1, %empty_tuple [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   %.loc16_3.2: %empty_struct_type = converted %.loc16_16.1, <error> [concrete = <error>]
-// CHECK:STDOUT:   assign %x.var, <error>
-// CHECK:STDOUT:   %.loc16_11.1: type = splice_block %.loc16_11.3 [concrete = constants.%empty_struct_type] {
-// CHECK:STDOUT:     %.loc16_11.2: %empty_struct_type = struct_literal ()
-// CHECK:STDOUT:     %.loc16_11.3: type = converted %.loc16_11.2, constants.%empty_struct_type [concrete = constants.%empty_struct_type]
+// CHECK:STDOUT:   %.loc15_9.1: type = splice_block %.loc15_9.3 [concrete = constants.%empty_struct_type] {
+// CHECK:STDOUT:     %.loc15_9.2: %empty_struct_type = struct_literal ()
+// CHECK:STDOUT:     %.loc15_9.3: type = converted %.loc15_9.2, constants.%empty_struct_type [concrete = constants.%empty_struct_type]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x: ref %empty_struct_type = bind_name x, %x.var
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: fn @__global_init() {
+// CHECK:STDOUT: !entry:
+// CHECK:STDOUT:   %.loc15_14.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:   %empty_tuple: %empty_tuple.type = tuple_value () [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   %.loc15_14.2: %empty_tuple.type = converted %.loc15_14.1, %empty_tuple [concrete = constants.%empty_tuple]
+// CHECK:STDOUT:   %.loc15_1: %empty_struct_type = converted %.loc15_14.1, <error> [concrete = <error>]
+// CHECK:STDOUT:   assign file.%x.var, <error>
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
diff --git a/toolchain/check/testdata/var/no_prelude/global_lookup_in_scope.carbon b/toolchain/check/testdata/var/no_prelude/global_lookup_in_scope.carbon
deleted file mode 100644
index ef255172a569..000000000000
--- a/toolchain/check/testdata/var/no_prelude/global_lookup_in_scope.carbon
+++ /dev/null
@@ -1,83 +0,0 @@
-// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
-// Exceptions. See /LICENSE for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-// AUTOUPDATE
-// TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/var/no_prelude/global_lookup_in_scope.carbon
-// TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/var/no_prelude/global_lookup_in_scope.carbon
-
-var x: {.v: ()} = {.v = ()};
-
-fn Main() {
-  var y: {.v: ()} = x;
-}
-
-// CHECK:STDOUT: --- global_lookup_in_scope.carbon
-// CHECK:STDOUT:
-// CHECK:STDOUT: constants {
-// CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
-// CHECK:STDOUT:   %struct_type.v: type = struct_type {.v: %empty_tuple.type} [concrete]
-// CHECK:STDOUT:   %empty_tuple: %empty_tuple.type = tuple_value () [concrete]
-// CHECK:STDOUT:   %struct: %struct_type.v = struct_value (%empty_tuple) [concrete]
-// CHECK:STDOUT:   %Main.type: type = fn_type @Main [concrete]
-// CHECK:STDOUT:   %Main: %Main.type = struct_value () [concrete]
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: file {
-// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
-// CHECK:STDOUT:     .x = %x
-// CHECK:STDOUT:     .Main = %Main.decl
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   name_binding_decl {
-// CHECK:STDOUT:     %x.patt: %struct_type.v = binding_pattern x
-// CHECK:STDOUT:     %.loc11_1: %struct_type.v = var_pattern %x.patt
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %x.var: ref %struct_type.v = var x
-// CHECK:STDOUT:   %.loc11_15: type = splice_block %struct_type.v [concrete = constants.%struct_type.v] {
-// CHECK:STDOUT:     %.loc11_14.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc11_14.2: type = converted %.loc11_14.1, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
-// CHECK:STDOUT:     %struct_type.v: type = struct_type {.v: %empty_tuple.type} [concrete = constants.%struct_type.v]
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %x: ref %struct_type.v = bind_name x, %x.var
-// CHECK:STDOUT:   %Main.decl: %Main.type = fn_decl @Main [concrete = constants.%Main] {} {}
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: fn @Main() {
-// CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   name_binding_decl {
-// CHECK:STDOUT:     %y.patt: %struct_type.v = binding_pattern y
-// CHECK:STDOUT:     %.loc14_3.1: %struct_type.v = var_pattern %y.patt
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %y.var: ref %struct_type.v = var y
-// CHECK:STDOUT:   %x.ref: ref %struct_type.v = name_ref x, file.%x
-// CHECK:STDOUT:   %.loc14_21.1: ref %empty_tuple.type = struct_access %x.ref, element0
-// CHECK:STDOUT:   %.loc14_21.2: ref %empty_tuple.type = struct_access %y.var, element0
-// CHECK:STDOUT:   %.loc14_21.3: init %empty_tuple.type = tuple_init () to %.loc14_21.2 [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   %.loc14_21.4: init %empty_tuple.type = converted %.loc14_21.1, %.loc14_21.3 [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   %.loc14_21.5: init %struct_type.v = struct_init (%.loc14_21.4) to %y.var [concrete = constants.%struct]
-// CHECK:STDOUT:   %.loc14_3.2: init %struct_type.v = converted %x.ref, %.loc14_21.5 [concrete = constants.%struct]
-// CHECK:STDOUT:   assign %y.var, %.loc14_3.2
-// CHECK:STDOUT:   %.loc14_17: type = splice_block %struct_type.v [concrete = constants.%struct_type.v] {
-// CHECK:STDOUT:     %.loc14_16.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc14_16.2: type = converted %.loc14_16.1, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
-// CHECK:STDOUT:     %struct_type.v: type = struct_type {.v: %empty_tuple.type} [concrete = constants.%struct_type.v]
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %y: ref %struct_type.v = bind_name y, %y.var
-// CHECK:STDOUT:   return
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: fn @__global_init() {
-// CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   %.loc11_26.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc11_27.1: %struct_type.v = struct_literal (%.loc11_26.1)
-// CHECK:STDOUT:   %.loc11_27.2: ref %empty_tuple.type = struct_access file.%x.var, element0
-// CHECK:STDOUT:   %.loc11_26.2: init %empty_tuple.type = tuple_init () to %.loc11_27.2 [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   %.loc11_27.3: init %empty_tuple.type = converted %.loc11_26.1, %.loc11_26.2 [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   %.loc11_27.4: init %struct_type.v = struct_init (%.loc11_27.3) to file.%x.var [concrete = constants.%struct]
-// CHECK:STDOUT:   %.loc11_1: init %struct_type.v = converted %.loc11_27.1, %.loc11_27.4 [concrete = constants.%struct]
-// CHECK:STDOUT:   assign file.%x.var, %.loc11_1
-// CHECK:STDOUT:   return
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
diff --git a/toolchain/check/testdata/var/no_prelude/shadowing.carbon b/toolchain/check/testdata/var/no_prelude/shadowing.carbon
deleted file mode 100644
index 9c6a6a0de89f..000000000000
--- a/toolchain/check/testdata/var/no_prelude/shadowing.carbon
+++ /dev/null
@@ -1,108 +0,0 @@
-// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
-// Exceptions. See /LICENSE for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-// AUTOUPDATE
-// TIP: To test this file alone, run:
-// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/var/no_prelude/shadowing.carbon
-// TIP: To dump output, run:
-// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/var/no_prelude/shadowing.carbon
-
-namespace NS;
-
-fn Main() {
-  var NS: () = ();
-  NS = ();
-
-  var x: () = ();
-  if (true) {
-    var x: () = ();
-
-    // TODO: We should reject this use of the shadowed variable `x`.
-    x = ();
-  }
-}
-
-// CHECK:STDOUT: --- shadowing.carbon
-// CHECK:STDOUT:
-// CHECK:STDOUT: constants {
-// CHECK:STDOUT:   %Main.type: type = fn_type @Main [concrete]
-// CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
-// CHECK:STDOUT:   %Main: %Main.type = struct_value () [concrete]
-// CHECK:STDOUT:   %empty_tuple: %empty_tuple.type = tuple_value () [concrete]
-// CHECK:STDOUT:   %true: bool = bool_literal true [concrete]
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: file {
-// CHECK:STDOUT:   package: <namespace> = namespace [concrete] {
-// CHECK:STDOUT:     .NS = %NS
-// CHECK:STDOUT:     .Main = %Main.decl
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %NS: <namespace> = namespace [concrete] {}
-// CHECK:STDOUT:   %Main.decl: %Main.type = fn_decl @Main [concrete = constants.%Main] {} {}
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: fn @Main() {
-// CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   name_binding_decl {
-// CHECK:STDOUT:     %NS.patt: %empty_tuple.type = binding_pattern NS
-// CHECK:STDOUT:     %.loc14_3.1: %empty_tuple.type = var_pattern %NS.patt
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %NS.var: ref %empty_tuple.type = var NS
-// CHECK:STDOUT:   %.loc14_17.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc14_17.2: init %empty_tuple.type = tuple_init () to %NS.var [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   %.loc14_3.2: init %empty_tuple.type = converted %.loc14_17.1, %.loc14_17.2 [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   assign %NS.var, %.loc14_3.2
-// CHECK:STDOUT:   %.loc14_12.1: type = splice_block %.loc14_12.3 [concrete = constants.%empty_tuple.type] {
-// CHECK:STDOUT:     %.loc14_12.2: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc14_12.3: type = converted %.loc14_12.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %NS: ref %empty_tuple.type = bind_name NS, %NS.var
-// CHECK:STDOUT:   %NS.ref: ref %empty_tuple.type = name_ref NS, %NS
-// CHECK:STDOUT:   %.loc15_9.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc15_9.2: init %empty_tuple.type = tuple_init () to %NS.ref [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   %.loc15_6: init %empty_tuple.type = converted %.loc15_9.1, %.loc15_9.2 [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   assign %NS.ref, %.loc15_6
-// CHECK:STDOUT:   name_binding_decl {
-// CHECK:STDOUT:     %x.patt.loc17: %empty_tuple.type = binding_pattern x
-// CHECK:STDOUT:     %.loc17_3.1: %empty_tuple.type = var_pattern %x.patt.loc17
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %x.var.loc17: ref %empty_tuple.type = var x
-// CHECK:STDOUT:   %.loc17_16.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc17_16.2: init %empty_tuple.type = tuple_init () to %x.var.loc17 [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   %.loc17_3.2: init %empty_tuple.type = converted %.loc17_16.1, %.loc17_16.2 [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   assign %x.var.loc17, %.loc17_3.2
-// CHECK:STDOUT:   %.loc17_11.1: type = splice_block %.loc17_11.3 [concrete = constants.%empty_tuple.type] {
-// CHECK:STDOUT:     %.loc17_11.2: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc17_11.3: type = converted %.loc17_11.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %x.loc17: ref %empty_tuple.type = bind_name x, %x.var.loc17
-// CHECK:STDOUT:   %true: bool = bool_literal true [concrete = constants.%true]
-// CHECK:STDOUT:   if %true br !if.then else br !if.else
-// CHECK:STDOUT:
-// CHECK:STDOUT: !if.then:
-// CHECK:STDOUT:   name_binding_decl {
-// CHECK:STDOUT:     %x.patt.loc19: %empty_tuple.type = binding_pattern x
-// CHECK:STDOUT:     %.loc19_5.1: %empty_tuple.type = var_pattern %x.patt.loc19
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %x.var.loc19: ref %empty_tuple.type = var x
-// CHECK:STDOUT:   %.loc19_18.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc19_18.2: init %empty_tuple.type = tuple_init () to %x.var.loc19 [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   %.loc19_5.2: init %empty_tuple.type = converted %.loc19_18.1, %.loc19_18.2 [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   assign %x.var.loc19, %.loc19_5.2
-// CHECK:STDOUT:   %.loc19_13.1: type = splice_block %.loc19_13.3 [concrete = constants.%empty_tuple.type] {
-// CHECK:STDOUT:     %.loc19_13.2: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc19_13.3: type = converted %.loc19_13.2, constants.%empty_tuple.type [concrete = constants.%empty_tuple.type]
-// CHECK:STDOUT:   }
-// CHECK:STDOUT:   %x.loc19: ref %empty_tuple.type = bind_name x, %x.var.loc19
-// CHECK:STDOUT:   %x.ref: ref %empty_tuple.type = name_ref x, %x.loc19
-// CHECK:STDOUT:   %.loc22_10.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc22_10.2: init %empty_tuple.type = tuple_init () to %x.ref [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   %.loc22_7: init %empty_tuple.type = converted %.loc22_10.1, %.loc22_10.2 [concrete = constants.%empty_tuple]
-// CHECK:STDOUT:   assign %x.ref, %.loc22_7
-// CHECK:STDOUT:   br !if.else
-// CHECK:STDOUT:
-// CHECK:STDOUT: !if.else:
-// CHECK:STDOUT:   return
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
diff --git a/toolchain/driver/testdata/fail_flush_errors.carbon b/toolchain/driver/testdata/fail_flush_errors.carbon
index bed01311cc50..c45a25622e26 100644
--- a/toolchain/driver/testdata/fail_flush_errors.carbon
+++ b/toolchain/driver/testdata/fail_flush_errors.carbon
@@ -2,7 +2,8 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
-// ARGS: --include-diagnostic-kind compile --no-prelude-import %s
+// INCLUDE-FILE: toolchain/testing/min_prelude/destroy.carbon
+// ARGS: --include-diagnostic-kind compile --custom-core %s
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
diff --git a/toolchain/testing/min_prelude/destroy.carbon b/toolchain/testing/min_prelude/destroy.carbon
new file mode 100644
index 000000000000..d40b38421d37
--- /dev/null
+++ b/toolchain/testing/min_prelude/destroy.carbon
@@ -0,0 +1,14 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+// A minimal prelude for tests that require destruction.
+package Core library "prelude";
+
+// TODO: Uncomment once the interface is used.
+// interface Destroy {
+//   fn Op[self: Self]();
+// }
+// impl forall [T:! type] T as Destroy {
+//   fn Op[self: Self]() = "no_op";
+// }