Model type expressions as regions (#4698)

This is a precondition for enabling the new pattern-matching subsystem
to support binding patterns that have `if` expressions in the type
position.

---------

Co-authored-by: Richard Smith <richard@metafoo.co.uk>

toolchain/check/testdata/function/definition/import.carbon

@@ -152,11 +152,13 @@ fn D() {}
 // CHECK:STDOUT:     %return.patt: %i32 = return_slot_pattern
 // CHECK:STDOUT:     %return.param_patt: %i32 = out_param_pattern %return.patt, runtime_param1
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %int_32.loc5_9: Core.IntLiteral = int_value 32 [template = constants.%int_32]
-// CHECK:STDOUT:     %i32.loc5_9: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
 // CHECK:STDOUT:     %int_32.loc5_17: Core.IntLiteral = int_value 32 [template = constants.%int_32]
 // CHECK:STDOUT:     %i32.loc5_17: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
 // CHECK:STDOUT:     %b.param: %i32 = value_param runtime_param0
+// CHECK:STDOUT:     %.loc5: type = splice_block %i32.loc5_9 [template = constants.%i32] {
+// CHECK:STDOUT:       %int_32.loc5_9: Core.IntLiteral = int_value 32 [template = constants.%int_32]
+// CHECK:STDOUT:       %i32.loc5_9: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
+// CHECK:STDOUT:     }
 // CHECK:STDOUT:     %b: %i32 = bind_name b, %b.param
 // CHECK:STDOUT:     %return.param: ref %i32 = out_param runtime_param1
 // CHECK:STDOUT:     %return: ref %i32 = return_slot %return.param
@@ -167,14 +169,16 @@ fn D() {}
 // CHECK:STDOUT:     %return.patt: %struct_type.c = return_slot_pattern
 // CHECK:STDOUT:     %return.param_patt: %struct_type.c = out_param_pattern %return.patt, runtime_param1
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %int_32.loc6_10: Core.IntLiteral = int_value 32 [template = constants.%int_32]
-// CHECK:STDOUT:     %i32.loc6_10: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
-// CHECK:STDOUT:     %.loc6_14.1: %tuple.type.1 = tuple_literal (%i32.loc6_10)
-// CHECK:STDOUT:     %.loc6_14.2: type = converted %.loc6_14.1, constants.%tuple.type.2 [template = constants.%tuple.type.2]
 // CHECK:STDOUT:     %int_32.loc6_25: Core.IntLiteral = int_value 32 [template = constants.%int_32]
 // CHECK:STDOUT:     %i32.loc6_25: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
 // CHECK:STDOUT:     %struct_type.c: type = struct_type {.c: %i32} [template = constants.%struct_type.c]
 // CHECK:STDOUT:     %c.param: %tuple.type.2 = value_param runtime_param0
+// CHECK:STDOUT:     %.loc6_14.3: type = splice_block %.loc6_14.2 [template = constants.%tuple.type.2] {
+// CHECK:STDOUT:       %int_32.loc6_10: Core.IntLiteral = int_value 32 [template = constants.%int_32]
+// CHECK:STDOUT:       %i32.loc6_10: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
+// CHECK:STDOUT:       %.loc6_14.1: %tuple.type.1 = tuple_literal (%i32.loc6_10)
+// CHECK:STDOUT:       %.loc6_14.2: type = converted %.loc6_14.1, constants.%tuple.type.2 [template = constants.%tuple.type.2]
+// CHECK:STDOUT:     }
 // CHECK:STDOUT:     %c: %tuple.type.2 = bind_name c, %c.param
 // CHECK:STDOUT:     %return.param: ref %struct_type.c = out_param runtime_param1
 // CHECK:STDOUT:     %return: ref %struct_type.c = return_slot %return.param
@@ -283,17 +287,10 @@ fn D() {}
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %default.import = import <invalid>
-// CHECK:STDOUT:   %.loc6_9.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc6_9.2: type = converted %.loc6_9.1, constants.%empty_tuple.type [template = constants.%empty_tuple.type]
 // CHECK:STDOUT:   %a.var: ref %empty_tuple.type = var a
 // CHECK:STDOUT:   %a: ref %empty_tuple.type = bind_name a, %a.var
-// CHECK:STDOUT:   %int_32.loc7: Core.IntLiteral = int_value 32 [template = constants.%int_32]
-// CHECK:STDOUT:   %i32.loc7: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
 // CHECK:STDOUT:   %b.var: ref %i32 = var b
 // CHECK:STDOUT:   %b: ref %i32 = bind_name b, %b.var
-// CHECK:STDOUT:   %int_32.loc8: Core.IntLiteral = int_value 32 [template = constants.%int_32]
-// CHECK:STDOUT:   %i32.loc8: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
-// CHECK:STDOUT:   %struct_type.c: type = struct_type {.c: %i32} [template = constants.%struct_type.c]
 // CHECK:STDOUT:   %c.var: ref %struct_type.c = var c
 // CHECK:STDOUT:   %c: ref %struct_type.c = bind_name c, %c.var
 // CHECK:STDOUT: }
@@ -368,11 +365,13 @@ fn D() {}
 // CHECK:STDOUT:   %default.import = import <invalid>
 // CHECK:STDOUT:   %A.decl: %A.type = fn_decl @A [template = constants.%A] {} {}
 // CHECK:STDOUT:   %B.decl: %B.type = fn_decl @B [template = constants.%B] {} {
-// CHECK:STDOUT:     %int_32.loc23_9: Core.IntLiteral = int_value 32 [template = constants.%int_32]
-// CHECK:STDOUT:     %i32.loc23_9: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
 // CHECK:STDOUT:     %int_32.loc23_17: Core.IntLiteral = int_value 32 [template = constants.%int_32]
 // CHECK:STDOUT:     %i32.loc23_17: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
 // CHECK:STDOUT:     %b.param: %i32 = value_param runtime_param0
+// CHECK:STDOUT:     %.loc23: type = splice_block %i32.loc23_9 [template = constants.%i32] {
+// CHECK:STDOUT:       %int_32.loc23_9: Core.IntLiteral = int_value 32 [template = constants.%int_32]
+// CHECK:STDOUT:       %i32.loc23_9: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
+// CHECK:STDOUT:     }
 // CHECK:STDOUT:     %b: %i32 = bind_name b, %b.param
 // CHECK:STDOUT:     %return.param: ref %i32 = out_param runtime_param1
 // CHECK:STDOUT:     %return: ref %i32 = return_slot %return.param

toolchain/check/testdata/function/definition/import_access.carbon

@@ -242,8 +242,6 @@ private fn Redecl() {}
 // CHECK:STDOUT:   %Test.import = import Test
 // CHECK:STDOUT:   %default.import = import <invalid>
 // CHECK:STDOUT:   %Core.import = import Core
-// CHECK:STDOUT:   %.loc4_9.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc4_9.2: type = converted %.loc4_9.1, constants.%empty_tuple.type [template = constants.%empty_tuple.type]
 // CHECK:STDOUT:   %f.var: ref %empty_tuple.type = var f
 // CHECK:STDOUT:   %f: ref %empty_tuple.type = bind_name f, %f.var
 // CHECK:STDOUT: }
@@ -278,8 +276,6 @@ private fn Redecl() {}
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %default.import = import <invalid>
-// CHECK:STDOUT:   %.loc10_9.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc10_9.2: type = converted %.loc10_9.1, constants.%empty_tuple.type [template = constants.%empty_tuple.type]
 // CHECK:STDOUT:   %f.var: ref %empty_tuple.type = var f
 // CHECK:STDOUT:   %f: ref %empty_tuple.type = bind_name f, %f.var
 // CHECK:STDOUT: }
@@ -315,8 +311,6 @@ private fn Redecl() {}
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Test.import = import Test
-// CHECK:STDOUT:   %.loc10_9.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc10_9.2: type = converted %.loc10_9.1, constants.%empty_tuple.type [template = constants.%empty_tuple.type]
 // CHECK:STDOUT:   %f.var: ref %empty_tuple.type = var f
 // CHECK:STDOUT:   %f: ref %empty_tuple.type = bind_name f, %f.var
 // CHECK:STDOUT: }
@@ -354,8 +348,6 @@ private fn Redecl() {}
 // CHECK:STDOUT:   %Test.import = import Test
 // CHECK:STDOUT:   %default.import = import <invalid>
 // CHECK:STDOUT:   %Core.import = import Core
-// CHECK:STDOUT:   %.loc4_9.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc4_9.2: type = converted %.loc4_9.1, constants.%empty_tuple.type [template = constants.%empty_tuple.type]
 // CHECK:STDOUT:   %f.var: ref %empty_tuple.type = var f
 // CHECK:STDOUT:   %f: ref %empty_tuple.type = bind_name f, %f.var
 // CHECK:STDOUT: }
@@ -390,8 +382,6 @@ private fn Redecl() {}
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %default.import = import <invalid>
-// CHECK:STDOUT:   %.loc10_9.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc10_9.2: type = converted %.loc10_9.1, constants.%empty_tuple.type [template = constants.%empty_tuple.type]
 // CHECK:STDOUT:   %f.var: ref %empty_tuple.type = var f
 // CHECK:STDOUT:   %f: ref %empty_tuple.type = bind_name f, %f.var
 // CHECK:STDOUT: }
@@ -427,8 +417,6 @@ private fn Redecl() {}
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Test.import = import Test
-// CHECK:STDOUT:   %.loc10_9.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc10_9.2: type = converted %.loc10_9.1, constants.%empty_tuple.type [template = constants.%empty_tuple.type]
 // CHECK:STDOUT:   %f.var: ref %empty_tuple.type = var f
 // CHECK:STDOUT:   %f: ref %empty_tuple.type = bind_name f, %f.var
 // CHECK:STDOUT: }
@@ -466,8 +454,6 @@ private fn Redecl() {}
 // CHECK:STDOUT:   %Test.import = import Test
 // CHECK:STDOUT:   %default.import = import <invalid>
 // CHECK:STDOUT:   %Core.import = import Core
-// CHECK:STDOUT:   %.loc4_9.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc4_9.2: type = converted %.loc4_9.1, constants.%empty_tuple.type [template = constants.%empty_tuple.type]
 // CHECK:STDOUT:   %f.var: ref %empty_tuple.type = var f
 // CHECK:STDOUT:   %f: ref %empty_tuple.type = bind_name f, %f.var
 // CHECK:STDOUT:   %Forward.decl: %Forward.type = fn_decl @Forward [template = constants.%Forward] {} {}
@@ -506,8 +492,6 @@ private fn Redecl() {}
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %default.import = import <invalid>
-// CHECK:STDOUT:   %.loc10_9.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc10_9.2: type = converted %.loc10_9.1, constants.%empty_tuple.type [template = constants.%empty_tuple.type]
 // CHECK:STDOUT:   %f.var: ref %empty_tuple.type = var f
 // CHECK:STDOUT:   %f: ref %empty_tuple.type = bind_name f, %f.var
 // CHECK:STDOUT: }
@@ -543,8 +527,6 @@ private fn Redecl() {}
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Core.import = import Core
 // CHECK:STDOUT:   %Test.import = import Test
-// CHECK:STDOUT:   %.loc9_9.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:   %.loc9_9.2: type = converted %.loc9_9.1, constants.%empty_tuple.type [template = constants.%empty_tuple.type]
 // CHECK:STDOUT:   %f.var: ref %empty_tuple.type = var f
 // CHECK:STDOUT:   %f: ref %empty_tuple.type = bind_name f, %f.var
 // CHECK:STDOUT: }

toolchain/check/testdata/function/definition/no_prelude/basics.carbon

@@ -39,8 +39,8 @@ fn F(n: C) {}
 // CHECK:STDOUT:     %n.patt: %C = binding_pattern n
 // CHECK:STDOUT:     %n.param_patt: %C = value_param_pattern %n.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %C.ref: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %n.param: %C = value_param runtime_param0
+// CHECK:STDOUT:     %C.ref: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %n: %C = bind_name n, %n.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }

toolchain/check/testdata/function/definition/no_prelude/fail_decl_param_mismatch.carbon

@@ -111,18 +111,22 @@ fn K() -> {} { return {}; }
 // CHECK:STDOUT:     %x.patt: %empty_tuple.type = binding_pattern x
 // CHECK:STDOUT:     %x.param_patt: %empty_tuple.type = value_param_pattern %x.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %.loc19_10.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc19_10.2: type = converted %.loc19_10.1, constants.%empty_tuple.type [template = constants.%empty_tuple.type]
 // CHECK:STDOUT:     %x.param: %empty_tuple.type = value_param runtime_param0
+// CHECK:STDOUT:     %.loc19_10.3: type = splice_block %.loc19_10.2 [template = constants.%empty_tuple.type] {
+// CHECK:STDOUT:       %.loc19_10.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:       %.loc19_10.2: type = converted %.loc19_10.1, constants.%empty_tuple.type [template = constants.%empty_tuple.type]
+// CHECK:STDOUT:     }
 // CHECK:STDOUT:     %x: %empty_tuple.type = bind_name x, %x.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %G.decl: %G.type = fn_decl @G [template = constants.%G] {
 // CHECK:STDOUT:     %x.patt: %empty_tuple.type = binding_pattern x
 // CHECK:STDOUT:     %x.param_patt: %empty_tuple.type = value_param_pattern %x.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %.loc21_10.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc21_10.2: type = converted %.loc21_10.1, constants.%empty_tuple.type [template = constants.%empty_tuple.type]
 // CHECK:STDOUT:     %x.param: %empty_tuple.type = value_param runtime_param0
+// CHECK:STDOUT:     %.loc21_10.3: type = splice_block %.loc21_10.2 [template = constants.%empty_tuple.type] {
+// CHECK:STDOUT:       %.loc21_10.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:       %.loc21_10.2: type = converted %.loc21_10.1, constants.%empty_tuple.type [template = constants.%empty_tuple.type]
+// CHECK:STDOUT:     }
 // CHECK:STDOUT:     %x: %empty_tuple.type = bind_name x, %x.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %.decl.loc29: %.type.2 = fn_decl @.2 [template = constants.%.2] {} {}
@@ -130,9 +134,11 @@ fn K() -> {} { return {}; }
 // CHECK:STDOUT:     %x.patt: %empty_tuple.type = binding_pattern x
 // CHECK:STDOUT:     %x.param_patt: %empty_tuple.type = value_param_pattern %x.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %.loc31_10.1: %empty_tuple.type = tuple_literal ()
-// CHECK:STDOUT:     %.loc31_10.2: type = converted %.loc31_10.1, constants.%empty_tuple.type [template = constants.%empty_tuple.type]
 // CHECK:STDOUT:     %x.param: %empty_tuple.type = value_param runtime_param0
+// CHECK:STDOUT:     %.loc31_10.3: type = splice_block %.loc31_10.2 [template = constants.%empty_tuple.type] {
+// CHECK:STDOUT:       %.loc31_10.1: %empty_tuple.type = tuple_literal ()
+// CHECK:STDOUT:       %.loc31_10.2: type = converted %.loc31_10.1, constants.%empty_tuple.type [template = constants.%empty_tuple.type]
+// CHECK:STDOUT:     }
 // CHECK:STDOUT:     %x: %empty_tuple.type = bind_name x, %x.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %.decl.loc36: %.type.3 = fn_decl @.3 [template = constants.%.3] {

toolchain/check/testdata/function/definition/no_prelude/fail_redef.carbon

@@ -35,8 +35,5 @@ fn F() {}
 // CHECK:STDOUT: fn @F() {
 // CHECK:STDOUT: !entry:
 // CHECK:STDOUT:   return
-// CHECK:STDOUT:
-// CHECK:STDOUT: !.loc18:
-// CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:

toolchain/check/testdata/function/definition/no_prelude/syntactic_merge.carbon

@@ -194,32 +194,32 @@ fn Foo(a: const (const C)) {}
 // CHECK:STDOUT:     %a.patt: %C = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %C = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %C.ref.loc7: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a.param.loc7: %C = value_param runtime_param0
+// CHECK:STDOUT:     %C.ref.loc7: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a.loc7: %C = bind_name a, %a.param.loc7
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Foo.decl.loc8: %Foo.type = fn_decl @Foo [template = constants.%Foo] {
 // CHECK:STDOUT:     %a.patt: %C = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %C = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %C.ref.loc8: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a.param.loc8: %C = value_param runtime_param0
+// CHECK:STDOUT:     %C.ref.loc8: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a.loc8: %C = bind_name a, %a.param.loc8
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Bar.decl.loc10: %Bar.type = fn_decl @Bar [template = constants.%Bar] {
 // CHECK:STDOUT:     %a.patt: %C = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %C = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %D.ref.loc10: type = name_ref D, file.%D [template = constants.%C]
 // CHECK:STDOUT:     %a.param.loc10: %C = value_param runtime_param0
+// CHECK:STDOUT:     %D.ref.loc10: type = name_ref D, file.%D [template = constants.%C]
 // CHECK:STDOUT:     %a.loc10: %C = bind_name a, %a.param.loc10
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Bar.decl.loc11: %Bar.type = fn_decl @Bar [template = constants.%Bar] {
 // CHECK:STDOUT:     %a.patt: %C = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %C = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %D.ref.loc11: type = name_ref D, file.%D [template = constants.%C]
 // CHECK:STDOUT:     %a.param.loc11: %C = value_param runtime_param0
+// CHECK:STDOUT:     %D.ref.loc11: type = name_ref D, file.%D [template = constants.%C]
 // CHECK:STDOUT:     %a.loc11: %C = bind_name a, %a.param.loc11
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
@@ -262,16 +262,16 @@ fn Foo(a: const (const C)) {}
 // CHECK:STDOUT:     %a.patt: %C = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %C = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %C.ref.loc6: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a.param.loc6: %C = value_param runtime_param0
+// CHECK:STDOUT:     %C.ref.loc6: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a.loc6: %C = bind_name a, %a.param.loc6
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Foo.decl.loc7: %Foo.type = fn_decl @Foo [template = constants.%Foo] {
 // CHECK:STDOUT:     %a.patt: %C = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %C = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %C.ref.loc7: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a.param.loc7: %C = value_param runtime_param0
+// CHECK:STDOUT:     %C.ref.loc7: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a.loc7: %C = bind_name a, %a.param.loc7
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
@@ -311,16 +311,16 @@ fn Foo(a: const (const C)) {}
 // CHECK:STDOUT:     %a.patt: %C = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %C = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %C.ref: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a.param: %C = value_param runtime_param0
+// CHECK:STDOUT:     %C.ref: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a: %C = bind_name a, %a.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %.decl: %.type = fn_decl @.1 [template = constants.%.1] {
 // CHECK:STDOUT:     %a.patt: %C = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %C = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %C.ref: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a.param: %C = value_param runtime_param0
+// CHECK:STDOUT:     %C.ref: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a: %C = bind_name a, %a.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
@@ -360,16 +360,16 @@ fn Foo(a: const (const C)) {}
 // CHECK:STDOUT:     %a.patt: %C = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %C = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %C.ref.loc6: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a.param.loc6: %C = value_param runtime_param0
+// CHECK:STDOUT:     %C.ref.loc6: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a.loc6: %C = bind_name a, %a.param.loc6
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Foo.decl.loc7: %Foo.type = fn_decl @Foo [template = constants.%Foo] {
 // CHECK:STDOUT:     %a.patt: %C = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %C = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %C.ref.loc7: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a.param.loc7: %C = value_param runtime_param0
+// CHECK:STDOUT:     %C.ref.loc7: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a.loc7: %C = bind_name a, %a.param.loc7
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
@@ -413,16 +413,16 @@ fn Foo(a: const (const C)) {}
 // CHECK:STDOUT:     %a.patt: %C = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %C = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %C.ref: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a.param: %C = value_param runtime_param0
+// CHECK:STDOUT:     %C.ref: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a: %C = bind_name a, %a.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Bar.decl: %Bar.type = fn_decl @Bar [template = constants.%Bar] {
 // CHECK:STDOUT:     %a.patt: %C = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %C = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %D.ref: type = name_ref D, file.%D [template = constants.%C]
 // CHECK:STDOUT:     %a.param: %C = value_param runtime_param0
+// CHECK:STDOUT:     %D.ref: type = name_ref D, file.%D [template = constants.%C]
 // CHECK:STDOUT:     %a: %C = bind_name a, %a.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
@@ -471,16 +471,16 @@ fn Foo(a: const (const C)) {}
 // CHECK:STDOUT:     %a.patt: %C = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %C = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %C.ref: type = name_ref C, imports.%import_ref.1 [template = constants.%C]
 // CHECK:STDOUT:     %a.param: %C = value_param runtime_param0
+// CHECK:STDOUT:     %C.ref: type = name_ref C, imports.%import_ref.1 [template = constants.%C]
 // CHECK:STDOUT:     %a: %C = bind_name a, %a.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %Bar.decl: %Bar.type = fn_decl @Bar [template = constants.%Bar] {
 // CHECK:STDOUT:     %a.patt: %C = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %C = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %D.ref: type = name_ref D, imports.%import_ref.2 [template = constants.%C]
 // CHECK:STDOUT:     %a.param: %C = value_param runtime_param0
+// CHECK:STDOUT:     %D.ref: type = name_ref D, imports.%import_ref.2 [template = constants.%C]
 // CHECK:STDOUT:     %a: %C = bind_name a, %a.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
@@ -526,16 +526,16 @@ fn Foo(a: const (const C)) {}
 // CHECK:STDOUT:     %a.patt: %C = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %C = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %C.ref: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a.param: %C = value_param runtime_param0
+// CHECK:STDOUT:     %C.ref: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a: %C = bind_name a, %a.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %.decl: %.type = fn_decl @.1 [template = constants.%.1] {
 // CHECK:STDOUT:     %b.patt: %C = binding_pattern b
 // CHECK:STDOUT:     %b.param_patt: %C = value_param_pattern %b.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %D.ref: type = name_ref D, file.%D [template = constants.%C]
 // CHECK:STDOUT:     %b.param: %C = value_param runtime_param0
+// CHECK:STDOUT:     %D.ref: type = name_ref D, file.%D [template = constants.%C]
 // CHECK:STDOUT:     %b: %C = bind_name b, %b.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
@@ -580,16 +580,16 @@ fn Foo(a: const (const C)) {}
 // CHECK:STDOUT:     %a.patt: %C = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %C = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %C.ref: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a.param: %C = value_param runtime_param0
+// CHECK:STDOUT:     %C.ref: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a: %C = bind_name a, %a.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %.decl: %.type = fn_decl @.1 [template = constants.%.1] {
 // CHECK:STDOUT:     %a.patt: %C = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %C = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %D.ref: type = name_ref D, file.%D [template = constants.%C]
 // CHECK:STDOUT:     %a.param: %C = value_param runtime_param0
+// CHECK:STDOUT:     %D.ref: type = name_ref D, file.%D [template = constants.%C]
 // CHECK:STDOUT:     %a: %C = bind_name a, %a.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
@@ -636,16 +636,16 @@ fn Foo(a: const (const C)) {}
 // CHECK:STDOUT:     %a.patt.loc7_8.1: %C = symbolic_binding_pattern a, 0 [symbolic = %a.patt.loc7_8.2 (constants.%a.patt)]
 // CHECK:STDOUT:     %a.param_patt: %C = value_param_pattern %a.patt.loc7_8.1, runtime_param<invalid> [symbolic = %a.patt.loc7_8.2 (constants.%a.patt)]
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %C.ref: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a.param: %C = value_param runtime_param<invalid>
+// CHECK:STDOUT:     %C.ref: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a.loc7_8.1: %C = bind_symbolic_name a, 0, %a.param [symbolic = %a.loc7_8.2 (constants.%a)]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %.decl: %.type = fn_decl @.1 [template = constants.%.1] {
 // CHECK:STDOUT:     %a.patt.loc15_8.1: %C = symbolic_binding_pattern a, 0 [symbolic = %a.patt.loc15_8.2 (constants.%a.patt)]
 // CHECK:STDOUT:     %a.param_patt: %C = value_param_pattern %a.patt.loc15_8.1, runtime_param<invalid> [symbolic = %a.patt.loc15_8.2 (constants.%a.patt)]
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %D.ref: type = name_ref D, file.%D [template = constants.%C]
 // CHECK:STDOUT:     %a.param: %C = value_param runtime_param<invalid>
+// CHECK:STDOUT:     %D.ref: type = name_ref D, file.%D [template = constants.%C]
 // CHECK:STDOUT:     %a.loc15_8.1: %C = bind_symbolic_name a, 0, %a.param [symbolic = %a.loc15_8.2 (constants.%a)]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
@@ -761,8 +761,8 @@ fn Foo(a: const (const C)) {}
 // CHECK:STDOUT:     %a.patt: %C = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %C = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %C.ref: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a.param: %C = value_param runtime_param0
+// CHECK:STDOUT:     %C.ref: type = name_ref C, file.%C.decl [template = constants.%C]
 // CHECK:STDOUT:     %a: %C = bind_name a, %a.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
@@ -807,8 +807,8 @@ fn Foo(a: const (const C)) {}
 // CHECK:STDOUT:     %a.patt: %C = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %C = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %D.ref: type = name_ref D, file.%D [template = constants.%C]
 // CHECK:STDOUT:     %a.param: %C = value_param runtime_param0
+// CHECK:STDOUT:     %D.ref: type = name_ref D, file.%D [template = constants.%C]
 // CHECK:STDOUT:     %a: %C = bind_name a, %a.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }
@@ -847,19 +847,23 @@ fn Foo(a: const (const C)) {}
 // CHECK:STDOUT:     %a.patt: %const = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %const = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %C.ref: type = name_ref C, file.%C.decl [template = constants.%C]
-// CHECK:STDOUT:     %const: type = const_type %C [template = constants.%const]
 // CHECK:STDOUT:     %a.param: %const = value_param runtime_param0
+// CHECK:STDOUT:     %.loc6: type = splice_block %const [template = constants.%const] {
+// CHECK:STDOUT:       %C.ref: type = name_ref C, file.%C.decl [template = constants.%C]
+// CHECK:STDOUT:       %const: type = const_type %C [template = constants.%const]
+// CHECK:STDOUT:     }
 // CHECK:STDOUT:     %a: %const = bind_name a, %a.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %.decl: %.type = fn_decl @.1 [template = constants.%.1] {
 // CHECK:STDOUT:     %a.patt: %const = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %const = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %C.ref: type = name_ref C, file.%C.decl [template = constants.%C]
-// CHECK:STDOUT:     %const.loc17_18: type = const_type %C [template = constants.%const]
-// CHECK:STDOUT:     %const.loc17_11: type = const_type %const [template = constants.%const]
 // CHECK:STDOUT:     %a.param: %const = value_param runtime_param0
+// CHECK:STDOUT:     %.loc17: type = splice_block %const.loc17_11 [template = constants.%const] {
+// CHECK:STDOUT:       %C.ref: type = name_ref C, file.%C.decl [template = constants.%C]
+// CHECK:STDOUT:       %const.loc17_18: type = const_type %C [template = constants.%const]
+// CHECK:STDOUT:       %const.loc17_11: type = const_type %const [template = constants.%const]
+// CHECK:STDOUT:     }
 // CHECK:STDOUT:     %a: %const = bind_name a, %a.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }

toolchain/check/testdata/function/definition/params_one.carbon

@@ -37,9 +37,11 @@ fn Foo(a: i32) {}
 // CHECK:STDOUT:     %a.patt: %i32 = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %i32 = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %int_32: Core.IntLiteral = int_value 32 [template = constants.%int_32]
-// CHECK:STDOUT:     %i32: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
 // CHECK:STDOUT:     %a.param: %i32 = value_param runtime_param0
+// CHECK:STDOUT:     %.loc11: type = splice_block %i32 [template = constants.%i32] {
+// CHECK:STDOUT:       %int_32: Core.IntLiteral = int_value 32 [template = constants.%int_32]
+// CHECK:STDOUT:       %i32: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
+// CHECK:STDOUT:     }
 // CHECK:STDOUT:     %a: %i32 = bind_name a, %a.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }

toolchain/check/testdata/function/definition/params_one_comma.carbon

@@ -37,9 +37,11 @@ fn Foo(a: i32,) {}
 // CHECK:STDOUT:     %a.patt: %i32 = binding_pattern a
 // CHECK:STDOUT:     %a.param_patt: %i32 = value_param_pattern %a.patt, runtime_param0
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %int_32: Core.IntLiteral = int_value 32 [template = constants.%int_32]
-// CHECK:STDOUT:     %i32: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
 // CHECK:STDOUT:     %a.param: %i32 = value_param runtime_param0
+// CHECK:STDOUT:     %.loc11: type = splice_block %i32 [template = constants.%i32] {
+// CHECK:STDOUT:       %int_32: Core.IntLiteral = int_value 32 [template = constants.%int_32]
+// CHECK:STDOUT:       %i32: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
+// CHECK:STDOUT:     }
 // CHECK:STDOUT:     %a: %i32 = bind_name a, %a.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }

toolchain/check/testdata/function/definition/params_two.carbon

@@ -39,13 +39,17 @@ fn Foo(a: i32, b: i32) {}
 // CHECK:STDOUT:     %b.patt: %i32 = binding_pattern b
 // CHECK:STDOUT:     %b.param_patt: %i32 = value_param_pattern %b.patt, runtime_param1
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %int_32.loc11_11: Core.IntLiteral = int_value 32 [template = constants.%int_32]
-// CHECK:STDOUT:     %i32.loc11_11: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
-// CHECK:STDOUT:     %int_32.loc11_19: Core.IntLiteral = int_value 32 [template = constants.%int_32]
-// CHECK:STDOUT:     %i32.loc11_19: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
 // CHECK:STDOUT:     %a.param: %i32 = value_param runtime_param0
+// CHECK:STDOUT:     %.loc11_11: type = splice_block %i32.loc11_11 [template = constants.%i32] {
+// CHECK:STDOUT:       %int_32.loc11_11: Core.IntLiteral = int_value 32 [template = constants.%int_32]
+// CHECK:STDOUT:       %i32.loc11_11: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
+// CHECK:STDOUT:     }
 // CHECK:STDOUT:     %a: %i32 = bind_name a, %a.param
 // CHECK:STDOUT:     %b.param: %i32 = value_param runtime_param1
+// CHECK:STDOUT:     %.loc11_19: type = splice_block %i32.loc11_19 [template = constants.%i32] {
+// CHECK:STDOUT:       %int_32.loc11_19: Core.IntLiteral = int_value 32 [template = constants.%int_32]
+// CHECK:STDOUT:       %i32.loc11_19: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
+// CHECK:STDOUT:     }
 // CHECK:STDOUT:     %b: %i32 = bind_name b, %b.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }

toolchain/check/testdata/function/definition/params_two_comma.carbon

@@ -39,13 +39,17 @@ fn Foo(a: i32, b: i32,) {}
 // CHECK:STDOUT:     %b.patt: %i32 = binding_pattern b
 // CHECK:STDOUT:     %b.param_patt: %i32 = value_param_pattern %b.patt, runtime_param1
 // CHECK:STDOUT:   } {
-// CHECK:STDOUT:     %int_32.loc11_11: Core.IntLiteral = int_value 32 [template = constants.%int_32]
-// CHECK:STDOUT:     %i32.loc11_11: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
-// CHECK:STDOUT:     %int_32.loc11_19: Core.IntLiteral = int_value 32 [template = constants.%int_32]
-// CHECK:STDOUT:     %i32.loc11_19: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
 // CHECK:STDOUT:     %a.param: %i32 = value_param runtime_param0
+// CHECK:STDOUT:     %.loc11_11: type = splice_block %i32.loc11_11 [template = constants.%i32] {
+// CHECK:STDOUT:       %int_32.loc11_11: Core.IntLiteral = int_value 32 [template = constants.%int_32]
+// CHECK:STDOUT:       %i32.loc11_11: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
+// CHECK:STDOUT:     }
 // CHECK:STDOUT:     %a: %i32 = bind_name a, %a.param
 // CHECK:STDOUT:     %b.param: %i32 = value_param runtime_param1
+// CHECK:STDOUT:     %.loc11_19: type = splice_block %i32.loc11_19 [template = constants.%i32] {
+// CHECK:STDOUT:       %int_32.loc11_19: Core.IntLiteral = int_value 32 [template = constants.%int_32]
+// CHECK:STDOUT:       %i32.loc11_19: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
+// CHECK:STDOUT:     }
 // CHECK:STDOUT:     %b: %i32 = bind_name b, %b.param
 // CHECK:STDOUT:   }
 // CHECK:STDOUT: }