Make C++ types impl Core.Default. (#6962)

C++ classes that are default-constructible now implement `Core.Default`
by calling the default constructor.

toolchain/check/testdata/interop/cpp/builtins.carbon

@@ -511,11 +511,16 @@ fn F() {
 // CHECK:STDOUT:   %unsigned_int: type = class_type @unsigned_int [concrete]
 // CHECK:STDOUT:   %pattern_type.5ec: type = pattern_type %unsigned_int [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.4c4: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%unsigned_int) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %unsigned_int, (%DefaultOrUnformed.impl_witness.4c4) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %unsigned_int.Op.type: type = fn_type @unsigned_int.Op [concrete]
+// CHECK:STDOUT:   %unsigned_int.Op: %unsigned_int.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.bd1: <witness> = custom_witness (%unsigned_int.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.6ad: %Default.type = facet_value %unsigned_int, (%custom_witness.bd1) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.099: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.6ad) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %unsigned_int, (%DefaultOrUnformed.impl_witness.099) [concrete]
 // CHECK:STDOUT:   %int_32: Core.IntLiteral = int_value 32 [concrete]
 // CHECK:STDOUT:   %u32: type = class_type @UInt, @UInt(%int_32) [concrete]
 // CHECK:STDOUT:   %pattern_type.4a9: type = pattern_type %u32 [concrete]
@@ -533,8 +538,8 @@ fn F() {
 // CHECK:STDOUT:     import Cpp//...
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %unsigned_int.decl: type = class_decl @unsigned_int [concrete = constants.%unsigned_int] {} {}
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT:   %unsigned_int.foo.cpp_overload_set.value: %unsigned_int.foo.cpp_overload_set.type = cpp_overload_set_value @unsigned_int.foo.cpp_overload_set [concrete = constants.%unsigned_int.foo.cpp_overload_set.value]
 // CHECK:STDOUT:   %unsigned_int.foo.decl: %unsigned_int.foo.type = fn_decl @unsigned_int.foo [concrete = constants.%unsigned_int.foo] {
 // CHECK:STDOUT:     %self.param_patt: %pattern_type.5ec = ref_param_pattern [concrete]
@@ -555,14 +560,14 @@ fn F() {
 // CHECK:STDOUT:     %unsigned_int.var_patt: %pattern_type.5ec = var_pattern %unsigned_int.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %unsigned_int.var: ref %unsigned_int = var %unsigned_int.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%unsigned_int, (constants.%DefaultOrUnformed.impl_witness.4c4) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%unsigned_int, (constants.%DefaultOrUnformed.impl_witness.099) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc12_38.1: %DefaultOrUnformed.type = converted constants.%unsigned_int, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc12_38.1 [concrete = constants.%unsigned_int]
 // CHECK:STDOUT:   %.loc12_38.2: type = converted %.loc12_38.1, %as_type [concrete = constants.%unsigned_int]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc12_3: ref %unsigned_int = splice_block %unsigned_int.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %unsigned_int to %.loc12_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign %unsigned_int.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %unsigned_int to %.loc12_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign %unsigned_int.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   %.loc12_25: type = splice_block %unsigned_int.ref.loc12 [concrete = constants.%unsigned_int] {
 // CHECK:STDOUT:     %Cpp.ref: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %unsigned_int.ref.loc12: type = name_ref unsigned_int, imports.%unsigned_int.decl [concrete = constants.%unsigned_int]

toolchain/check/testdata/interop/cpp/class/constructor.carbon

@@ -21,6 +21,10 @@ class C {
   C();
 };
 
+struct NoDefault {
+  NoDefault(int);
+};
+
 // --- import_default.carbon
 
 library "[[@TEST_NAME]]";
@@ -33,6 +37,59 @@ fn F() {
   //@dump-sem-ir-end
 }
 
+// --- implicit_default.carbon
+
+library "[[@TEST_NAME]]";
+
+import Cpp library "default.h";
+
+fn F() {
+  //@dump-sem-ir-begin
+  var unused c: Cpp.C;
+  //@dump-sem-ir-end
+}
+
+fn G(T:! Core.Default & Core.Destroy) {
+  var unused x: T;
+}
+
+fn CallG() {
+  G(Cpp.C);
+}
+
+// --- todo_fail_no_default_decl.carbon
+
+library "[[@TEST_NAME]]";
+
+import Cpp library "default.h";
+
+fn F() {
+  // TODO: This should fail, but currently does not because the min_prelude
+  // version of UnformedInit is currently implemented by every type.
+  var unused x: Cpp.NoDefault;
+}
+
+// --- fail_no_default.carbon
+
+library "[[@TEST_NAME]]";
+
+import Cpp library "default.h";
+
+fn G(T:! Core.Default & Core.Destroy) {
+  var unused x: T;
+}
+
+fn CallG() {
+  // CHECK:STDERR: fail_no_default.carbon:[[@LINE+7]]:3: error: cannot convert type `NoDefault` into type implementing `Core.Default & Core.Destroy` [ConversionFailureTypeToFacet]
+  // CHECK:STDERR:   G(Cpp.NoDefault);
+  // CHECK:STDERR:   ^~~~~~~~~~~~~~~~
+  // CHECK:STDERR: fail_no_default.carbon:[[@LINE-8]]:6: note: initializing generic parameter `T` declared here [InitializingGenericParam]
+  // CHECK:STDERR: fn G(T:! Core.Default & Core.Destroy) {
+  // CHECK:STDERR:      ^
+  // CHECK:STDERR:
+  G(Cpp.NoDefault);
+}
+
 // ============================================================================
 // Non default constructor
 // ============================================================================
@@ -308,6 +365,62 @@ fn F() {
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: --- implicit_default.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: constants {
+// CHECK:STDOUT:   %empty_tuple.type: type = tuple_type () [concrete]
+// CHECK:STDOUT:   %C: type = class_type @C [concrete]
+// CHECK:STDOUT:   %pattern_type.217: type = pattern_type %C [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %C.Op.type: type = fn_type @C.Op [concrete]
+// CHECK:STDOUT:   %C.Op: %C.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.a0a: <witness> = custom_witness (%C.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.fdc: %Default.type = facet_value %C, (%custom_witness.a0a) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.2aa: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.fdc) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.898: %DefaultOrUnformed.type = facet_value %C, (%DefaultOrUnformed.impl_witness.2aa) [concrete]
+// CHECK:STDOUT:   %C.cpp_destructor.type: type = fn_type @C.cpp_destructor [concrete]
+// CHECK:STDOUT:   %C.cpp_destructor: %C.cpp_destructor.type = struct_value () [concrete]
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: imports {
+// CHECK:STDOUT:   %Cpp: <namespace> = namespace file.%Cpp.import_cpp, [concrete] {
+// CHECK:STDOUT:     .C = %C.decl
+// CHECK:STDOUT:     import Cpp//...
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %C.decl: type = class_decl @C [concrete = constants.%C] {} {}
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: fn @F() {
+// CHECK:STDOUT: !entry:
+// CHECK:STDOUT:   name_binding_decl {
+// CHECK:STDOUT:     %c.patt: %pattern_type.217 = ref_binding_pattern c [concrete]
+// CHECK:STDOUT:     %c.var_patt: %pattern_type.217 = var_pattern %c.patt [concrete]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %c.var: ref %C = var %c.var_patt
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%C, (constants.%DefaultOrUnformed.impl_witness.2aa) [concrete = constants.%DefaultOrUnformed.facet.898]
+// CHECK:STDOUT:   %.loc8_22.1: %DefaultOrUnformed.type = converted constants.%C, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet.898]
+// CHECK:STDOUT:   %as_type: type = facet_access_type %.loc8_22.1 [concrete = constants.%C]
+// CHECK:STDOUT:   %.loc8_22.2: type = converted %.loc8_22.1, %as_type [concrete = constants.%C]
+// CHECK:STDOUT:   <elided>
+// CHECK:STDOUT:   %.loc8_3: ref %C = splice_block %c.var {}
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %C to %.loc8_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign %c.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %.loc8_20: type = splice_block %C.ref [concrete = constants.%C] {
+// CHECK:STDOUT:     %Cpp.ref: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
+// CHECK:STDOUT:     %C.ref: type = name_ref C, imports.%C.decl [concrete = constants.%C]
+// CHECK:STDOUT:   }
+// CHECK:STDOUT:   %c: ref %C = ref_binding c, %c.var
+// CHECK:STDOUT:   %C.cpp_destructor.bound: <bound method> = bound_method %c.var, constants.%C.cpp_destructor
+// CHECK:STDOUT:   %C.cpp_destructor.call: init %empty_tuple.type = call %C.cpp_destructor.bound(%c.var)
+// CHECK:STDOUT:   <elided>
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: --- import_non_default.carbon
 // CHECK:STDOUT:
 // CHECK:STDOUT: constants {

toolchain/check/testdata/interop/cpp/function/class.carbon

@@ -653,11 +653,16 @@ fn F() {
 // CHECK:STDOUT:   %foo__carbon_thunk.type: type = fn_type @foo__carbon_thunk [concrete]
 // CHECK:STDOUT:   %foo__carbon_thunk: %foo__carbon_thunk.type = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.6df: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%C) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %C, (%DefaultOrUnformed.impl_witness.6df) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %C.Op.type: type = fn_type @C.Op [concrete]
+// CHECK:STDOUT:   %C.Op: %C.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.cb7: <witness> = custom_witness (%C.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.0fd: %Default.type = facet_value %C, (%custom_witness.cb7) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.5a3: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.0fd) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %C, (%DefaultOrUnformed.impl_witness.5a3) [concrete]
 // CHECK:STDOUT:   %C.cpp_destructor.type: type = fn_type @C.cpp_destructor [concrete]
 // CHECK:STDOUT:   %C.cpp_destructor: %C.cpp_destructor.type = struct_value () [concrete]
 // CHECK:STDOUT: }
@@ -679,8 +684,8 @@ fn F() {
 // CHECK:STDOUT:   } {
 // CHECK:STDOUT:     <elided>
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @F(%c.param: %C) {
@@ -696,14 +701,14 @@ fn F() {
 // CHECK:STDOUT:     %x.var_patt: %pattern_type.69f = var_pattern %x.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x.var: ref %C = var %x.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%C, (constants.%DefaultOrUnformed.impl_witness.6df) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%C, (constants.%DefaultOrUnformed.impl_witness.5a3) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc10_24.1: %DefaultOrUnformed.type = converted constants.%C, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc10_24.1 [concrete = constants.%C]
 // CHECK:STDOUT:   %.loc10_24.2: type = converted %.loc10_24.1, %as_type [concrete = constants.%C]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc10_3: ref %C = splice_block %x.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %C to %.loc10_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign %x.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %C to %.loc10_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign %x.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   %.loc10_22: type = splice_block %C.ref.loc10 [concrete = constants.%C] {
 // CHECK:STDOUT:     %Cpp.ref.loc10: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %N.ref.loc10: <namespace> = name_ref N, imports.%N [concrete = imports.%N]
@@ -775,11 +780,16 @@ fn F() {
 // CHECK:STDOUT:   %foo__carbon_thunk: %foo__carbon_thunk.type = struct_value () [concrete]
 // CHECK:STDOUT:   %pattern_type.cff: type = pattern_type %O [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.938: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%O) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %O, (%DefaultOrUnformed.impl_witness.938) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %O.Op.type: type = fn_type @O.Op [concrete]
+// CHECK:STDOUT:   %O.Op: %O.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.8f6: <witness> = custom_witness (%O.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.d7b: %Default.type = facet_value %O, (%custom_witness.8f6) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.e05: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.d7b) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %O, (%DefaultOrUnformed.impl_witness.e05) [concrete]
 // CHECK:STDOUT:   %O.cpp_destructor.type: type = fn_type @O.cpp_destructor [concrete]
 // CHECK:STDOUT:   %O.cpp_destructor: %O.cpp_destructor.type = struct_value () [concrete]
 // CHECK:STDOUT: }
@@ -797,8 +807,8 @@ fn F() {
 // CHECK:STDOUT:   } {
 // CHECK:STDOUT:     <elided>
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @F(%c.param: %C) {
@@ -814,14 +824,14 @@ fn F() {
 // CHECK:STDOUT:     %x.var_patt: %pattern_type.cff = var_pattern %x.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x.var: ref %O = var %x.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%O, (constants.%DefaultOrUnformed.impl_witness.938) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%O, (constants.%DefaultOrUnformed.impl_witness.e05) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc9_22.1: %DefaultOrUnformed.type = converted constants.%O, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc9_22.1 [concrete = constants.%O]
 // CHECK:STDOUT:   %.loc9_22.2: type = converted %.loc9_22.1, %as_type [concrete = constants.%O]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc9_3: ref %O = splice_block %x.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %O to %.loc9_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign %x.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %O to %.loc9_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign %x.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   %.loc9_20: type = splice_block %O.ref.loc9 [concrete = constants.%O] {
 // CHECK:STDOUT:     %Cpp.ref.loc9: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %O.ref.loc9: type = name_ref O, imports.%O.decl [concrete = constants.%O]

toolchain/check/testdata/interop/cpp/function/reference.carbon

@@ -381,18 +381,27 @@ fn F() {
 // CHECK:STDOUT:   %S: type = class_type @S [concrete]
 // CHECK:STDOUT:   %pattern_type.7da: type = pattern_type %S [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.6b7: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%S) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.d8f: %DefaultOrUnformed.type = facet_value %S, (%DefaultOrUnformed.impl_witness.6b7) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %S.Op.type: type = fn_type @S.Op [concrete]
+// CHECK:STDOUT:   %S.Op: %S.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.4cd: <witness> = custom_witness (%S.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.889: %Default.type = facet_value %S, (%custom_witness.4cd) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.a91: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.889) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.b0b: %DefaultOrUnformed.type = facet_value %S, (%DefaultOrUnformed.impl_witness.a91) [concrete]
 // CHECK:STDOUT:   %TakesLValue.cpp_overload_set.type: type = cpp_overload_set_type @TakesLValue.cpp_overload_set [concrete]
 // CHECK:STDOUT:   %TakesLValue.cpp_overload_set.value: %TakesLValue.cpp_overload_set.type = cpp_overload_set_value @TakesLValue.cpp_overload_set [concrete]
 // CHECK:STDOUT:   %const: type = const_type %S [concrete]
 // CHECK:STDOUT:   %T.e15: type = class_type @T [concrete]
 // CHECK:STDOUT:   %pattern_type.e6b: type = pattern_type %T.e15 [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.a11: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%T.e15) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.5fe: %DefaultOrUnformed.type = facet_value %T.e15, (%DefaultOrUnformed.impl_witness.a11) [concrete]
+// CHECK:STDOUT:   %T.Op.type: type = fn_type @T.Op [concrete]
+// CHECK:STDOUT:   %T.Op: %T.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.3b9: <witness> = custom_witness (%T.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.2fe: %Default.type = facet_value %T.e15, (%custom_witness.3b9) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.1bd: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.2fe) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.ac4: %DefaultOrUnformed.type = facet_value %T.e15, (%DefaultOrUnformed.impl_witness.1bd) [concrete]
 // CHECK:STDOUT:   %S.cpp_destructor.type: type = fn_type @S.cpp_destructor [concrete]
 // CHECK:STDOUT:   %S.cpp_destructor: %S.cpp_destructor.type = struct_value () [concrete]
 // CHECK:STDOUT:   %T.cpp_destructor.type: type = fn_type @T.cpp_destructor [concrete]
@@ -407,8 +416,8 @@ fn F() {
 // CHECK:STDOUT:     import Cpp//...
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %S.decl: type = class_decl @S [concrete = constants.%S] {} {}
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT:   %TakesLValue.cpp_overload_set.value: %TakesLValue.cpp_overload_set.type = cpp_overload_set_value @TakesLValue.cpp_overload_set [concrete = constants.%TakesLValue.cpp_overload_set.value]
 // CHECK:STDOUT:   %T.decl: type = class_decl @T [concrete = constants.%T.e15] {} {}
 // CHECK:STDOUT: }
@@ -420,14 +429,14 @@ fn F() {
 // CHECK:STDOUT:     %v.var_patt: %pattern_type.7da = var_pattern %v.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %v.var: ref %S = var %v.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc8: %DefaultOrUnformed.type = facet_value constants.%S, (constants.%DefaultOrUnformed.impl_witness.6b7) [concrete = constants.%DefaultOrUnformed.facet.d8f]
-// CHECK:STDOUT:   %.loc8_15.1: %DefaultOrUnformed.type = converted constants.%S, %DefaultOrUnformed.facet.loc8 [concrete = constants.%DefaultOrUnformed.facet.d8f]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc8: %DefaultOrUnformed.type = facet_value constants.%S, (constants.%DefaultOrUnformed.impl_witness.a91) [concrete = constants.%DefaultOrUnformed.facet.b0b]
+// CHECK:STDOUT:   %.loc8_15.1: %DefaultOrUnformed.type = converted constants.%S, %DefaultOrUnformed.facet.loc8 [concrete = constants.%DefaultOrUnformed.facet.b0b]
 // CHECK:STDOUT:   %as_type.loc8: type = facet_access_type %.loc8_15.1 [concrete = constants.%S]
 // CHECK:STDOUT:   %.loc8_15.2: type = converted %.loc8_15.1, %as_type.loc8 [concrete = constants.%S]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc8_3: ref %S = splice_block %v.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call.loc8: init %S to %.loc8_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn.1()
-// CHECK:STDOUT:   assign %v.var, %T.as.DefaultOrUnformed.impl.Op.call.loc8
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc8: init %S to %.loc8_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn.1()
+// CHECK:STDOUT:   assign %v.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc8
 // CHECK:STDOUT:   %.loc8_13: type = splice_block %S.ref.loc8 [concrete = constants.%S] {
 // CHECK:STDOUT:     %Cpp.ref.loc8: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %S.ref.loc8: type = name_ref S, imports.%S.decl [concrete = constants.%S]
@@ -459,14 +468,14 @@ fn F() {
 // CHECK:STDOUT:     %t.var_patt: %pattern_type.e6b = var_pattern %t.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %t.var: ref %T.e15 = var %t.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc30: %DefaultOrUnformed.type = facet_value constants.%T.e15, (constants.%DefaultOrUnformed.impl_witness.a11) [concrete = constants.%DefaultOrUnformed.facet.5fe]
-// CHECK:STDOUT:   %.loc30_15.1: %DefaultOrUnformed.type = converted constants.%T.e15, %DefaultOrUnformed.facet.loc30 [concrete = constants.%DefaultOrUnformed.facet.5fe]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc30: %DefaultOrUnformed.type = facet_value constants.%T.e15, (constants.%DefaultOrUnformed.impl_witness.1bd) [concrete = constants.%DefaultOrUnformed.facet.ac4]
+// CHECK:STDOUT:   %.loc30_15.1: %DefaultOrUnformed.type = converted constants.%T.e15, %DefaultOrUnformed.facet.loc30 [concrete = constants.%DefaultOrUnformed.facet.ac4]
 // CHECK:STDOUT:   %as_type.loc30: type = facet_access_type %.loc30_15.1 [concrete = constants.%T.e15]
 // CHECK:STDOUT:   %.loc30_15.2: type = converted %.loc30_15.1, %as_type.loc30 [concrete = constants.%T.e15]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc30_3: ref %T.e15 = splice_block %t.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call.loc30: init %T.e15 to %.loc30_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn.2()
-// CHECK:STDOUT:   assign %t.var, %T.as.DefaultOrUnformed.impl.Op.call.loc30
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc30: init %T.e15 to %.loc30_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn.2()
+// CHECK:STDOUT:   assign %t.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc30
 // CHECK:STDOUT:   %.loc30_13: type = splice_block %T.ref [concrete = constants.%T.e15] {
 // CHECK:STDOUT:     %Cpp.ref.loc30: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %T.ref: type = name_ref T, imports.%T.decl [concrete = constants.%T.e15]
@@ -480,14 +489,14 @@ fn F() {
 // CHECK:STDOUT:     %u.var_patt: %pattern_type.7da = var_pattern %u.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %u.var: ref %S = var %u.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc41: %DefaultOrUnformed.type = facet_value constants.%S, (constants.%DefaultOrUnformed.impl_witness.6b7) [concrete = constants.%DefaultOrUnformed.facet.d8f]
-// CHECK:STDOUT:   %.loc41_15.1: %DefaultOrUnformed.type = converted constants.%S, %DefaultOrUnformed.facet.loc41 [concrete = constants.%DefaultOrUnformed.facet.d8f]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc41: %DefaultOrUnformed.type = facet_value constants.%S, (constants.%DefaultOrUnformed.impl_witness.a91) [concrete = constants.%DefaultOrUnformed.facet.b0b]
+// CHECK:STDOUT:   %.loc41_15.1: %DefaultOrUnformed.type = converted constants.%S, %DefaultOrUnformed.facet.loc41 [concrete = constants.%DefaultOrUnformed.facet.b0b]
 // CHECK:STDOUT:   %as_type.loc41: type = facet_access_type %.loc41_15.1 [concrete = constants.%S]
 // CHECK:STDOUT:   %.loc41_15.2: type = converted %.loc41_15.1, %as_type.loc41 [concrete = constants.%S]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc41_3: ref %S = splice_block %u.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call.loc41: init %S to %.loc41_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn.3()
-// CHECK:STDOUT:   assign %u.var, %T.as.DefaultOrUnformed.impl.Op.call.loc41
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc41: init %S to %.loc41_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn.3()
+// CHECK:STDOUT:   assign %u.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc41
 // CHECK:STDOUT:   %.loc41_13: type = splice_block %S.ref.loc41 [concrete = constants.%S] {
 // CHECK:STDOUT:     %Cpp.ref.loc41: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %S.ref.loc41: type = name_ref S, imports.%S.decl [concrete = constants.%S]
@@ -570,17 +579,26 @@ fn F() {
 // CHECK:STDOUT:   %empty_struct_type: type = struct_type {} [concrete]
 // CHECK:STDOUT:   %pattern_type.7da: type = pattern_type %S [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T.67d: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T.67d) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.6b7: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%S) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.d8f: %DefaultOrUnformed.type = facet_value %S, (%DefaultOrUnformed.impl_witness.6b7) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %S.Op.type: type = fn_type @S.Op [concrete]
+// CHECK:STDOUT:   %S.Op: %S.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.4cd: <witness> = custom_witness (%S.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.889: %Default.type = facet_value %S, (%custom_witness.4cd) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.a91: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.889) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.b0b: %DefaultOrUnformed.type = facet_value %S, (%DefaultOrUnformed.impl_witness.a91) [concrete]
 // CHECK:STDOUT:   %TakesRValue.cpp_overload_set.type: type = cpp_overload_set_type @TakesRValue.cpp_overload_set [concrete]
 // CHECK:STDOUT:   %TakesRValue.cpp_overload_set.value: %TakesRValue.cpp_overload_set.type = cpp_overload_set_value @TakesRValue.cpp_overload_set [concrete]
 // CHECK:STDOUT:   %T.e15: type = class_type @T [concrete]
 // CHECK:STDOUT:   %pattern_type.e6b: type = pattern_type %T.e15 [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.a11: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%T.e15) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.5fe: %DefaultOrUnformed.type = facet_value %T.e15, (%DefaultOrUnformed.impl_witness.a11) [concrete]
+// CHECK:STDOUT:   %T.Op.type: type = fn_type @T.Op [concrete]
+// CHECK:STDOUT:   %T.Op: %T.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.3b9: <witness> = custom_witness (%T.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.2fe: %Default.type = facet_value %T.e15, (%custom_witness.3b9) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.1bd: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.2fe) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.ac4: %DefaultOrUnformed.type = facet_value %T.e15, (%DefaultOrUnformed.impl_witness.1bd) [concrete]
 // CHECK:STDOUT:   %empty_struct.a40: %empty_struct_type = struct_value () [concrete]
 // CHECK:STDOUT:   %S.val: %S = struct_value () [concrete]
 // CHECK:STDOUT:   %const: type = const_type %S [concrete]
@@ -599,8 +617,8 @@ fn F() {
 // CHECK:STDOUT:     import Cpp//...
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %S.decl: type = class_decl @S [concrete = constants.%S] {} {}
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT:   %TakesRValue.cpp_overload_set.value: %TakesRValue.cpp_overload_set.type = cpp_overload_set_value @TakesRValue.cpp_overload_set [concrete = constants.%TakesRValue.cpp_overload_set.value]
 // CHECK:STDOUT:   %T.decl: type = class_decl @T [concrete = constants.%T.e15] {} {}
 // CHECK:STDOUT: }
@@ -612,14 +630,14 @@ fn F() {
 // CHECK:STDOUT:     %s.var_patt: %pattern_type.7da = var_pattern %s.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %s.var: ref %S = var %s.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc8: %DefaultOrUnformed.type = facet_value constants.%S, (constants.%DefaultOrUnformed.impl_witness.6b7) [concrete = constants.%DefaultOrUnformed.facet.d8f]
-// CHECK:STDOUT:   %.loc8_15.1: %DefaultOrUnformed.type = converted constants.%S, %DefaultOrUnformed.facet.loc8 [concrete = constants.%DefaultOrUnformed.facet.d8f]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc8: %DefaultOrUnformed.type = facet_value constants.%S, (constants.%DefaultOrUnformed.impl_witness.a91) [concrete = constants.%DefaultOrUnformed.facet.b0b]
+// CHECK:STDOUT:   %.loc8_15.1: %DefaultOrUnformed.type = converted constants.%S, %DefaultOrUnformed.facet.loc8 [concrete = constants.%DefaultOrUnformed.facet.b0b]
 // CHECK:STDOUT:   %as_type.loc8: type = facet_access_type %.loc8_15.1 [concrete = constants.%S]
 // CHECK:STDOUT:   %.loc8_15.2: type = converted %.loc8_15.1, %as_type.loc8 [concrete = constants.%S]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc8_3: ref %S = splice_block %s.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call.loc8: init %S to %.loc8_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn.1()
-// CHECK:STDOUT:   assign %s.var, %T.as.DefaultOrUnformed.impl.Op.call.loc8
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc8: init %S to %.loc8_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn.1()
+// CHECK:STDOUT:   assign %s.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc8
 // CHECK:STDOUT:   %.loc8_13: type = splice_block %S.ref.loc8 [concrete = constants.%S] {
 // CHECK:STDOUT:     %Cpp.ref.loc8: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %S.ref.loc8: type = name_ref S, imports.%S.decl [concrete = constants.%S]
@@ -633,14 +651,14 @@ fn F() {
 // CHECK:STDOUT:     %t.var_patt: %pattern_type.e6b = var_pattern %t.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %t.var: ref %T.e15 = var %t.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc19: %DefaultOrUnformed.type = facet_value constants.%T.e15, (constants.%DefaultOrUnformed.impl_witness.a11) [concrete = constants.%DefaultOrUnformed.facet.5fe]
-// CHECK:STDOUT:   %.loc19_15.1: %DefaultOrUnformed.type = converted constants.%T.e15, %DefaultOrUnformed.facet.loc19 [concrete = constants.%DefaultOrUnformed.facet.5fe]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc19: %DefaultOrUnformed.type = facet_value constants.%T.e15, (constants.%DefaultOrUnformed.impl_witness.1bd) [concrete = constants.%DefaultOrUnformed.facet.ac4]
+// CHECK:STDOUT:   %.loc19_15.1: %DefaultOrUnformed.type = converted constants.%T.e15, %DefaultOrUnformed.facet.loc19 [concrete = constants.%DefaultOrUnformed.facet.ac4]
 // CHECK:STDOUT:   %as_type.loc19: type = facet_access_type %.loc19_15.1 [concrete = constants.%T.e15]
 // CHECK:STDOUT:   %.loc19_15.2: type = converted %.loc19_15.1, %as_type.loc19 [concrete = constants.%T.e15]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc19_3: ref %T.e15 = splice_block %t.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call.loc19: init %T.e15 to %.loc19_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn.2()
-// CHECK:STDOUT:   assign %t.var, %T.as.DefaultOrUnformed.impl.Op.call.loc19
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc19: init %T.e15 to %.loc19_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn.2()
+// CHECK:STDOUT:   assign %t.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc19
 // CHECK:STDOUT:   %.loc19_13: type = splice_block %T.ref [concrete = constants.%T.e15] {
 // CHECK:STDOUT:     %Cpp.ref.loc19: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %T.ref: type = name_ref T, imports.%T.decl [concrete = constants.%T.e15]

toolchain/check/testdata/interop/cpp/function/struct.carbon

@@ -652,11 +652,16 @@ fn F() {
 // CHECK:STDOUT:   %foo__carbon_thunk.type: type = fn_type @foo__carbon_thunk [concrete]
 // CHECK:STDOUT:   %foo__carbon_thunk: %foo__carbon_thunk.type = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.590: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%S) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %S, (%DefaultOrUnformed.impl_witness.590) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %S.Op.type: type = fn_type @S.Op [concrete]
+// CHECK:STDOUT:   %S.Op: %S.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.4c9: <witness> = custom_witness (%S.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.dcf: %Default.type = facet_value %S, (%custom_witness.4c9) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.33e: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.dcf) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %S, (%DefaultOrUnformed.impl_witness.33e) [concrete]
 // CHECK:STDOUT:   %S.cpp_destructor.type: type = fn_type @S.cpp_destructor [concrete]
 // CHECK:STDOUT:   %S.cpp_destructor: %S.cpp_destructor.type = struct_value () [concrete]
 // CHECK:STDOUT: }
@@ -678,8 +683,8 @@ fn F() {
 // CHECK:STDOUT:   } {
 // CHECK:STDOUT:     <elided>
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @F(%s.param: %S) {
@@ -695,14 +700,14 @@ fn F() {
 // CHECK:STDOUT:     %x.var_patt: %pattern_type.cd8 = var_pattern %x.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x.var: ref %S = var %x.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%S, (constants.%DefaultOrUnformed.impl_witness.590) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%S, (constants.%DefaultOrUnformed.impl_witness.33e) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc10_24.1: %DefaultOrUnformed.type = converted constants.%S, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc10_24.1 [concrete = constants.%S]
 // CHECK:STDOUT:   %.loc10_24.2: type = converted %.loc10_24.1, %as_type [concrete = constants.%S]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc10_3: ref %S = splice_block %x.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %S to %.loc10_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign %x.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %S to %.loc10_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign %x.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   %.loc10_22: type = splice_block %S.ref.loc10 [concrete = constants.%S] {
 // CHECK:STDOUT:     %Cpp.ref.loc10: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %N.ref.loc10: <namespace> = name_ref N, imports.%N [concrete = imports.%N]
@@ -774,11 +779,16 @@ fn F() {
 // CHECK:STDOUT:   %foo__carbon_thunk: %foo__carbon_thunk.type = struct_value () [concrete]
 // CHECK:STDOUT:   %pattern_type.cff: type = pattern_type %O [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.938: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%O) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %O, (%DefaultOrUnformed.impl_witness.938) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %O.Op.type: type = fn_type @O.Op [concrete]
+// CHECK:STDOUT:   %O.Op: %O.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.8f6: <witness> = custom_witness (%O.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.d7b: %Default.type = facet_value %O, (%custom_witness.8f6) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.e05: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.d7b) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %O, (%DefaultOrUnformed.impl_witness.e05) [concrete]
 // CHECK:STDOUT:   %O.cpp_destructor.type: type = fn_type @O.cpp_destructor [concrete]
 // CHECK:STDOUT:   %O.cpp_destructor: %O.cpp_destructor.type = struct_value () [concrete]
 // CHECK:STDOUT: }
@@ -796,8 +806,8 @@ fn F() {
 // CHECK:STDOUT:   } {
 // CHECK:STDOUT:     <elided>
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @F(%s.param: %S) {
@@ -813,14 +823,14 @@ fn F() {
 // CHECK:STDOUT:     %x.var_patt: %pattern_type.cff = var_pattern %x.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x.var: ref %O = var %x.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%O, (constants.%DefaultOrUnformed.impl_witness.938) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%O, (constants.%DefaultOrUnformed.impl_witness.e05) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc9_22.1: %DefaultOrUnformed.type = converted constants.%O, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc9_22.1 [concrete = constants.%O]
 // CHECK:STDOUT:   %.loc9_22.2: type = converted %.loc9_22.1, %as_type [concrete = constants.%O]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc9_3: ref %O = splice_block %x.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %O to %.loc9_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign %x.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %O to %.loc9_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign %x.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   %.loc9_20: type = splice_block %O.ref.loc9 [concrete = constants.%O] {
 // CHECK:STDOUT:     %Cpp.ref.loc9: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %O.ref.loc9: type = name_ref O, imports.%O.decl [concrete = constants.%O]

toolchain/check/testdata/interop/cpp/function/union.carbon

@@ -577,11 +577,16 @@ fn F() {
 // CHECK:STDOUT:   %foo__carbon_thunk.type: type = fn_type @foo__carbon_thunk [concrete]
 // CHECK:STDOUT:   %foo__carbon_thunk: %foo__carbon_thunk.type = struct_value () [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.860: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%U) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %U, (%DefaultOrUnformed.impl_witness.860) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %U.Op.type: type = fn_type @U.Op [concrete]
+// CHECK:STDOUT:   %U.Op: %U.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.cb9: <witness> = custom_witness (%U.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.916: %Default.type = facet_value %U, (%custom_witness.cb9) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.225: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.916) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %U, (%DefaultOrUnformed.impl_witness.225) [concrete]
 // CHECK:STDOUT:   %U.cpp_destructor.type: type = fn_type @U.cpp_destructor [concrete]
 // CHECK:STDOUT:   %U.cpp_destructor: %U.cpp_destructor.type = struct_value () [concrete]
 // CHECK:STDOUT: }
@@ -603,8 +608,8 @@ fn F() {
 // CHECK:STDOUT:   } {
 // CHECK:STDOUT:     <elided>
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @F(%u.param: %U) {
@@ -620,14 +625,14 @@ fn F() {
 // CHECK:STDOUT:     %x.var_patt: %pattern_type.eb9 = var_pattern %x.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x.var: ref %U = var %x.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%U, (constants.%DefaultOrUnformed.impl_witness.860) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%U, (constants.%DefaultOrUnformed.impl_witness.225) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc10_24.1: %DefaultOrUnformed.type = converted constants.%U, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc10_24.1 [concrete = constants.%U]
 // CHECK:STDOUT:   %.loc10_24.2: type = converted %.loc10_24.1, %as_type [concrete = constants.%U]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc10_3: ref %U = splice_block %x.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %U to %.loc10_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign %x.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %U to %.loc10_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign %x.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   %.loc10_22: type = splice_block %U.ref.loc10 [concrete = constants.%U] {
 // CHECK:STDOUT:     %Cpp.ref.loc10: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %N.ref.loc10: <namespace> = name_ref N, imports.%N [concrete = imports.%N]
@@ -699,11 +704,16 @@ fn F() {
 // CHECK:STDOUT:   %foo__carbon_thunk: %foo__carbon_thunk.type = struct_value () [concrete]
 // CHECK:STDOUT:   %pattern_type.cff: type = pattern_type %O [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.938: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%O) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %O, (%DefaultOrUnformed.impl_witness.938) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %O.Op.type: type = fn_type @O.Op [concrete]
+// CHECK:STDOUT:   %O.Op: %O.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.8f6: <witness> = custom_witness (%O.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.d7b: %Default.type = facet_value %O, (%custom_witness.8f6) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.e05: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.d7b) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %O, (%DefaultOrUnformed.impl_witness.e05) [concrete]
 // CHECK:STDOUT:   %O.cpp_destructor.type: type = fn_type @O.cpp_destructor [concrete]
 // CHECK:STDOUT:   %O.cpp_destructor: %O.cpp_destructor.type = struct_value () [concrete]
 // CHECK:STDOUT: }
@@ -721,8 +731,8 @@ fn F() {
 // CHECK:STDOUT:   } {
 // CHECK:STDOUT:     <elided>
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @F(%u.param: %U) {
@@ -738,14 +748,14 @@ fn F() {
 // CHECK:STDOUT:     %x.var_patt: %pattern_type.cff = var_pattern %x.patt [concrete]
 // CHECK:STDOUT:   }
 // CHECK:STDOUT:   %x.var: ref %O = var %x.var_patt
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%O, (constants.%DefaultOrUnformed.impl_witness.938) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%O, (constants.%DefaultOrUnformed.impl_witness.e05) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc9_22.1: %DefaultOrUnformed.type = converted constants.%O, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc9_22.1 [concrete = constants.%O]
 // CHECK:STDOUT:   %.loc9_22.2: type = converted %.loc9_22.1, %as_type [concrete = constants.%O]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc9_3: ref %O = splice_block %x.var {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %O to %.loc9_3 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign %x.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %O to %.loc9_3 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign %x.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   %.loc9_20: type = splice_block %O.ref.loc9 [concrete = constants.%O] {
 // CHECK:STDOUT:     %Cpp.ref.loc9: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
 // CHECK:STDOUT:     %O.ref.loc9: type = name_ref O, imports.%O.decl [concrete = constants.%O]

toolchain/check/testdata/interop/cpp/template/argument_count.carbon

@@ -124,16 +124,21 @@ var too_many: Cpp.FixedSizePack(Cpp.A, Cpp.A).Inner(Cpp.B, Cpp.B, Cpp.B);
 // CHECK:STDOUT:   %TwoTypes: type = class_type @TwoTypes [concrete]
 // CHECK:STDOUT:   %pattern_type.2da: type = pattern_type %TwoTypes [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.679: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%TwoTypes) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %TwoTypes, (%DefaultOrUnformed.impl_witness.679) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %TwoTypes.Op.type: type = fn_type @TwoTypes.Op [concrete]
+// CHECK:STDOUT:   %TwoTypes.Op: %TwoTypes.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.2e3: <witness> = custom_witness (%TwoTypes.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.c59: %Default.type = facet_value %TwoTypes, (%custom_witness.2e3) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.fcc: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.c59) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %TwoTypes, (%DefaultOrUnformed.impl_witness.fcc) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
@@ -147,14 +152,14 @@ var too_many: Cpp.FixedSizePack(Cpp.A, Cpp.A).Inner(Cpp.B, Cpp.B, Cpp.B);
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @__global_init() {
 // CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%TwoTypes, (constants.%DefaultOrUnformed.impl_witness.679) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%TwoTypes, (constants.%DefaultOrUnformed.impl_witness.fcc) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc7_34.1: %DefaultOrUnformed.type = converted constants.%TwoTypes, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc7_34.1 [concrete = constants.%TwoTypes]
 // CHECK:STDOUT:   %.loc7_34.2: type = converted %.loc7_34.1, %as_type [concrete = constants.%TwoTypes]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc7_1: ref %TwoTypes = splice_block file.%x.var [concrete = file.%x.var] {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %TwoTypes to %.loc7_1 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign file.%x.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %TwoTypes to %.loc7_1 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign file.%x.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -164,28 +169,45 @@ var too_many: Cpp.FixedSizePack(Cpp.A, Cpp.A).Inner(Cpp.B, Cpp.B, Cpp.B);
 // CHECK:STDOUT:   %TypePack.49edc4.1: type = class_type @TypePack.1 [concrete]
 // CHECK:STDOUT:   %pattern_type.9db866.1: type = pattern_type %TypePack.49edc4.1 [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.bca864.1: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%TypePack.49edc4.1) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.95dbcc.1: %DefaultOrUnformed.type = facet_value %TypePack.49edc4.1, (%DefaultOrUnformed.impl_witness.bca864.1) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %TypePack.Op.type.c6ed4b.1: type = fn_type @TypePack.Op.1 [concrete]
+// CHECK:STDOUT:   %TypePack.Op.4bf03f.1: %TypePack.Op.type.c6ed4b.1 = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.969c90.1: <witness> = custom_witness (%TypePack.Op.4bf03f.1), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.314ffa.1: %Default.type = facet_value %TypePack.49edc4.1, (%custom_witness.969c90.1) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.fd05a0.1: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.314ffa.1) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.7756c0.1: %DefaultOrUnformed.type = facet_value %TypePack.49edc4.1, (%DefaultOrUnformed.impl_witness.fd05a0.1) [concrete]
 // CHECK:STDOUT:   %TypePack.49edc4.2: type = class_type @TypePack.2 [concrete]
 // CHECK:STDOUT:   %pattern_type.9db866.2: type = pattern_type %TypePack.49edc4.2 [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.bca864.2: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%TypePack.49edc4.2) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.95dbcc.2: %DefaultOrUnformed.type = facet_value %TypePack.49edc4.2, (%DefaultOrUnformed.impl_witness.bca864.2) [concrete]
+// CHECK:STDOUT:   %TypePack.Op.type.c6ed4b.2: type = fn_type @TypePack.Op.2 [concrete]
+// CHECK:STDOUT:   %TypePack.Op.4bf03f.2: %TypePack.Op.type.c6ed4b.2 = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.969c90.2: <witness> = custom_witness (%TypePack.Op.4bf03f.2), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.314ffa.2: %Default.type = facet_value %TypePack.49edc4.2, (%custom_witness.969c90.2) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.fd05a0.2: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.314ffa.2) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.7756c0.2: %DefaultOrUnformed.type = facet_value %TypePack.49edc4.2, (%DefaultOrUnformed.impl_witness.fd05a0.2) [concrete]
 // CHECK:STDOUT:   %TypePack.49edc4.3: type = class_type @TypePack.3 [concrete]
 // CHECK:STDOUT:   %pattern_type.9db866.3: type = pattern_type %TypePack.49edc4.3 [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.bca864.3: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%TypePack.49edc4.3) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.95dbcc.3: %DefaultOrUnformed.type = facet_value %TypePack.49edc4.3, (%DefaultOrUnformed.impl_witness.bca864.3) [concrete]
+// CHECK:STDOUT:   %TypePack.Op.type.c6ed4b.3: type = fn_type @TypePack.Op.3 [concrete]
+// CHECK:STDOUT:   %TypePack.Op.4bf03f.3: %TypePack.Op.type.c6ed4b.3 = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.969c90.3: <witness> = custom_witness (%TypePack.Op.4bf03f.3), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.314ffa.3: %Default.type = facet_value %TypePack.49edc4.3, (%custom_witness.969c90.3) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.fd05a0.3: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.314ffa.3) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.7756c0.3: %DefaultOrUnformed.type = facet_value %TypePack.49edc4.3, (%DefaultOrUnformed.impl_witness.fd05a0.3) [concrete]
 // CHECK:STDOUT:   %TypePack.49edc4.4: type = class_type @TypePack.4 [concrete]
 // CHECK:STDOUT:   %pattern_type.9db866.4: type = pattern_type %TypePack.49edc4.4 [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.bca864.4: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%TypePack.49edc4.4) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.95dbcc.4: %DefaultOrUnformed.type = facet_value %TypePack.49edc4.4, (%DefaultOrUnformed.impl_witness.bca864.4) [concrete]
+// CHECK:STDOUT:   %TypePack.Op.type.c6ed4b.4: type = fn_type @TypePack.Op.4 [concrete]
+// CHECK:STDOUT:   %TypePack.Op.4bf03f.4: %TypePack.Op.type.c6ed4b.4 = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.969c90.4: <witness> = custom_witness (%TypePack.Op.4bf03f.4), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.314ffa.4: %Default.type = facet_value %TypePack.49edc4.4, (%custom_witness.969c90.4) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.fd05a0.4: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.314ffa.4) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.7756c0.4: %DefaultOrUnformed.type = facet_value %TypePack.49edc4.4, (%DefaultOrUnformed.impl_witness.fd05a0.4) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
@@ -217,38 +239,38 @@ var too_many: Cpp.FixedSizePack(Cpp.A, Cpp.A).Inner(Cpp.B, Cpp.B, Cpp.B);
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @__global_init() {
 // CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc7: %DefaultOrUnformed.type = facet_value constants.%TypePack.49edc4.1, (constants.%DefaultOrUnformed.impl_witness.bca864.1) [concrete = constants.%DefaultOrUnformed.facet.95dbcc.1]
-// CHECK:STDOUT:   %.loc7_23.1: %DefaultOrUnformed.type = converted constants.%TypePack.49edc4.1, %DefaultOrUnformed.facet.loc7 [concrete = constants.%DefaultOrUnformed.facet.95dbcc.1]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc7: %DefaultOrUnformed.type = facet_value constants.%TypePack.49edc4.1, (constants.%DefaultOrUnformed.impl_witness.fd05a0.1) [concrete = constants.%DefaultOrUnformed.facet.7756c0.1]
+// CHECK:STDOUT:   %.loc7_23.1: %DefaultOrUnformed.type = converted constants.%TypePack.49edc4.1, %DefaultOrUnformed.facet.loc7 [concrete = constants.%DefaultOrUnformed.facet.7756c0.1]
 // CHECK:STDOUT:   %as_type.loc7: type = facet_access_type %.loc7_23.1 [concrete = constants.%TypePack.49edc4.1]
 // CHECK:STDOUT:   %.loc7_23.2: type = converted %.loc7_23.1, %as_type.loc7 [concrete = constants.%TypePack.49edc4.1]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc7_1: ref %TypePack.49edc4.1 = splice_block file.%a0.var [concrete = file.%a0.var] {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call.loc7: init %TypePack.49edc4.1 to %.loc7_1 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn.1()
-// CHECK:STDOUT:   assign file.%a0.var, %T.as.DefaultOrUnformed.impl.Op.call.loc7
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc8: %DefaultOrUnformed.type = facet_value constants.%TypePack.49edc4.2, (constants.%DefaultOrUnformed.impl_witness.bca864.2) [concrete = constants.%DefaultOrUnformed.facet.95dbcc.2]
-// CHECK:STDOUT:   %.loc8_28.1: %DefaultOrUnformed.type = converted constants.%TypePack.49edc4.2, %DefaultOrUnformed.facet.loc8 [concrete = constants.%DefaultOrUnformed.facet.95dbcc.2]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc7: init %TypePack.49edc4.1 to %.loc7_1 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn.1()
+// CHECK:STDOUT:   assign file.%a0.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc7
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc8: %DefaultOrUnformed.type = facet_value constants.%TypePack.49edc4.2, (constants.%DefaultOrUnformed.impl_witness.fd05a0.2) [concrete = constants.%DefaultOrUnformed.facet.7756c0.2]
+// CHECK:STDOUT:   %.loc8_28.1: %DefaultOrUnformed.type = converted constants.%TypePack.49edc4.2, %DefaultOrUnformed.facet.loc8 [concrete = constants.%DefaultOrUnformed.facet.7756c0.2]
 // CHECK:STDOUT:   %as_type.loc8: type = facet_access_type %.loc8_28.1 [concrete = constants.%TypePack.49edc4.2]
 // CHECK:STDOUT:   %.loc8_28.2: type = converted %.loc8_28.1, %as_type.loc8 [concrete = constants.%TypePack.49edc4.2]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc8_1: ref %TypePack.49edc4.2 = splice_block file.%a1.var [concrete = file.%a1.var] {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call.loc8: init %TypePack.49edc4.2 to %.loc8_1 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn.2()
-// CHECK:STDOUT:   assign file.%a1.var, %T.as.DefaultOrUnformed.impl.Op.call.loc8
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc9: %DefaultOrUnformed.type = facet_value constants.%TypePack.49edc4.3, (constants.%DefaultOrUnformed.impl_witness.bca864.3) [concrete = constants.%DefaultOrUnformed.facet.95dbcc.3]
-// CHECK:STDOUT:   %.loc9_35.1: %DefaultOrUnformed.type = converted constants.%TypePack.49edc4.3, %DefaultOrUnformed.facet.loc9 [concrete = constants.%DefaultOrUnformed.facet.95dbcc.3]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc8: init %TypePack.49edc4.2 to %.loc8_1 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn.2()
+// CHECK:STDOUT:   assign file.%a1.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc8
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc9: %DefaultOrUnformed.type = facet_value constants.%TypePack.49edc4.3, (constants.%DefaultOrUnformed.impl_witness.fd05a0.3) [concrete = constants.%DefaultOrUnformed.facet.7756c0.3]
+// CHECK:STDOUT:   %.loc9_35.1: %DefaultOrUnformed.type = converted constants.%TypePack.49edc4.3, %DefaultOrUnformed.facet.loc9 [concrete = constants.%DefaultOrUnformed.facet.7756c0.3]
 // CHECK:STDOUT:   %as_type.loc9: type = facet_access_type %.loc9_35.1 [concrete = constants.%TypePack.49edc4.3]
 // CHECK:STDOUT:   %.loc9_35.2: type = converted %.loc9_35.1, %as_type.loc9 [concrete = constants.%TypePack.49edc4.3]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc9_1: ref %TypePack.49edc4.3 = splice_block file.%a2.var [concrete = file.%a2.var] {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call.loc9: init %TypePack.49edc4.3 to %.loc9_1 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn.3()
-// CHECK:STDOUT:   assign file.%a2.var, %T.as.DefaultOrUnformed.impl.Op.call.loc9
-// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc10: %DefaultOrUnformed.type = facet_value constants.%TypePack.49edc4.4, (constants.%DefaultOrUnformed.impl_witness.bca864.4) [concrete = constants.%DefaultOrUnformed.facet.95dbcc.4]
-// CHECK:STDOUT:   %.loc10_42.1: %DefaultOrUnformed.type = converted constants.%TypePack.49edc4.4, %DefaultOrUnformed.facet.loc10 [concrete = constants.%DefaultOrUnformed.facet.95dbcc.4]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc9: init %TypePack.49edc4.3 to %.loc9_1 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn.3()
+// CHECK:STDOUT:   assign file.%a2.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc9
+// CHECK:STDOUT:   %DefaultOrUnformed.facet.loc10: %DefaultOrUnformed.type = facet_value constants.%TypePack.49edc4.4, (constants.%DefaultOrUnformed.impl_witness.fd05a0.4) [concrete = constants.%DefaultOrUnformed.facet.7756c0.4]
+// CHECK:STDOUT:   %.loc10_42.1: %DefaultOrUnformed.type = converted constants.%TypePack.49edc4.4, %DefaultOrUnformed.facet.loc10 [concrete = constants.%DefaultOrUnformed.facet.7756c0.4]
 // CHECK:STDOUT:   %as_type.loc10: type = facet_access_type %.loc10_42.1 [concrete = constants.%TypePack.49edc4.4]
 // CHECK:STDOUT:   %.loc10_42.2: type = converted %.loc10_42.1, %as_type.loc10 [concrete = constants.%TypePack.49edc4.4]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc10_1: ref %TypePack.49edc4.4 = splice_block file.%a3.var [concrete = file.%a3.var] {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call.loc10: init %TypePack.49edc4.4 to %.loc10_1 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn.4()
-// CHECK:STDOUT:   assign file.%a3.var, %T.as.DefaultOrUnformed.impl.Op.call.loc10
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc10: init %TypePack.49edc4.4 to %.loc10_1 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn.4()
+// CHECK:STDOUT:   assign file.%a3.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call.loc10
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT: }
 // CHECK:STDOUT:

toolchain/check/testdata/interop/cpp/template/template_template_param.carbon

@@ -86,16 +86,21 @@ var x: Cpp.TwoTemplates(Cpp.A, true);
 // CHECK:STDOUT:   %TwoTemplates: type = class_type @TwoTemplates [concrete]
 // CHECK:STDOUT:   %pattern_type.2b7: type = pattern_type %TwoTemplates [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.cea: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%TwoTemplates) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %TwoTemplates, (%DefaultOrUnformed.impl_witness.cea) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %TwoTemplates.Op.type: type = fn_type @TwoTemplates.Op [concrete]
+// CHECK:STDOUT:   %TwoTemplates.Op: %TwoTemplates.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.6e5: <witness> = custom_witness (%TwoTemplates.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.90a: %Default.type = facet_value %TwoTemplates, (%custom_witness.6e5) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.18b: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.90a) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %TwoTemplates, (%DefaultOrUnformed.impl_witness.18b) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
@@ -109,14 +114,14 @@ var x: Cpp.TwoTemplates(Cpp.A, true);
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @__global_init() {
 // CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%TwoTemplates, (constants.%DefaultOrUnformed.impl_witness.cea) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%TwoTemplates, (constants.%DefaultOrUnformed.impl_witness.18b) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc7_38.1: %DefaultOrUnformed.type = converted constants.%TwoTemplates, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc7_38.1 [concrete = constants.%TwoTemplates]
 // CHECK:STDOUT:   %.loc7_38.2: type = converted %.loc7_38.1, %as_type [concrete = constants.%TwoTemplates]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc7_1: ref %TwoTemplates = splice_block file.%x.var [concrete = file.%x.var] {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %TwoTemplates to %.loc7_1 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign file.%x.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %TwoTemplates to %.loc7_1 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign file.%x.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT: }
 // CHECK:STDOUT:

toolchain/check/testdata/interop/cpp/template/type_param.carbon

@@ -70,16 +70,21 @@ var x: Cpp.TwoTypes(Cpp.A, {});
 // CHECK:STDOUT:   %TwoTypes: type = class_type @TwoTypes [concrete]
 // CHECK:STDOUT:   %pattern_type.2da: type = pattern_type %TwoTypes [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.679: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%TwoTypes) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %TwoTypes, (%DefaultOrUnformed.impl_witness.679) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %TwoTypes.Op.type: type = fn_type @TwoTypes.Op [concrete]
+// CHECK:STDOUT:   %TwoTypes.Op: %TwoTypes.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.2e3: <witness> = custom_witness (%TwoTypes.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.c59: %Default.type = facet_value %TwoTypes, (%custom_witness.2e3) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.fcc: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.c59) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %TwoTypes, (%DefaultOrUnformed.impl_witness.fcc) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
@@ -93,14 +98,14 @@ var x: Cpp.TwoTypes(Cpp.A, {});
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @__global_init() {
 // CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%TwoTypes, (constants.%DefaultOrUnformed.impl_witness.679) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%TwoTypes, (constants.%DefaultOrUnformed.impl_witness.fcc) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc7_34.1: %DefaultOrUnformed.type = converted constants.%TwoTypes, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc7_34.1 [concrete = constants.%TwoTypes]
 // CHECK:STDOUT:   %.loc7_34.2: type = converted %.loc7_34.1, %as_type [concrete = constants.%TwoTypes]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc7_1: ref %TwoTypes = splice_block file.%x.var [concrete = file.%x.var] {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %TwoTypes to %.loc7_1 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign file.%x.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %TwoTypes to %.loc7_1 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign file.%x.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -110,16 +115,21 @@ var x: Cpp.TwoTypes(Cpp.A, {});
 // CHECK:STDOUT:   %TwoTypes: type = class_type @TwoTypes [concrete]
 // CHECK:STDOUT:   %pattern_type.2da: type = pattern_type %TwoTypes [concrete]
 // CHECK:STDOUT:   %DefaultOrUnformed.type: type = facet_type <@DefaultOrUnformed> [concrete]
-// CHECK:STDOUT:   %T: type = symbolic_binding T, 0 [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.type.6c6: type = fn_type @T.as.DefaultOrUnformed.impl.Op, @T.as.DefaultOrUnformed.impl(%T) [symbolic]
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.ae1: %T.as.DefaultOrUnformed.impl.Op.type.6c6 = struct_value () [symbolic]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.679: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table, @T.as.DefaultOrUnformed.impl(%TwoTypes) [concrete]
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %TwoTypes, (%DefaultOrUnformed.impl_witness.679) [concrete]
+// CHECK:STDOUT:   %Default.type: type = facet_type <@Default> [concrete]
+// CHECK:STDOUT:   %T.50c: %Default.type = symbolic_binding T, 0 [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1: type = fn_type @T.binding.as_type.as.DefaultOrUnformed.impl.Op, @T.binding.as_type.as.DefaultOrUnformed.impl(%T.50c) [symbolic]
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.185: %T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1 = struct_value () [symbolic]
+// CHECK:STDOUT:   %TwoTypes.Op.type: type = fn_type @TwoTypes.Op [concrete]
+// CHECK:STDOUT:   %TwoTypes.Op: %TwoTypes.Op.type = struct_value () [concrete]
+// CHECK:STDOUT:   %custom_witness.2e3: <witness> = custom_witness (%TwoTypes.Op), @Default [concrete]
+// CHECK:STDOUT:   %Default.facet.c59: %Default.type = facet_value %TwoTypes, (%custom_witness.2e3) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness.fcc: <witness> = impl_witness imports.%DefaultOrUnformed.impl_witness_table.608, @T.binding.as_type.as.DefaultOrUnformed.impl(%Default.facet.c59) [concrete]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value %TwoTypes, (%DefaultOrUnformed.impl_witness.fcc) [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
-// CHECK:STDOUT:   %Core.import_ref.01d: @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op.type (%T.as.DefaultOrUnformed.impl.Op.type.6c6) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.as.DefaultOrUnformed.impl.%T.as.DefaultOrUnformed.impl.Op (constants.%T.as.DefaultOrUnformed.impl.Op.ae1)]
-// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table = impl_witness_table (%Core.import_ref.01d), @T.as.DefaultOrUnformed.impl [concrete]
+// CHECK:STDOUT:   %Core.import_ref.9c6: @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type (%T.binding.as_type.as.DefaultOrUnformed.impl.Op.type.8d1) = import_ref Core//prelude/parts/default, loc{{\d+_\d+}}, loaded [symbolic = @T.binding.as_type.as.DefaultOrUnformed.impl.%T.binding.as_type.as.DefaultOrUnformed.impl.Op (constants.%T.binding.as_type.as.DefaultOrUnformed.impl.Op.185)]
+// CHECK:STDOUT:   %DefaultOrUnformed.impl_witness_table.608 = impl_witness_table (%Core.import_ref.9c6), @T.binding.as_type.as.DefaultOrUnformed.impl [concrete]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: file {
@@ -133,14 +143,14 @@ var x: Cpp.TwoTypes(Cpp.A, {});
 // CHECK:STDOUT:
 // CHECK:STDOUT: fn @__global_init() {
 // CHECK:STDOUT: !entry:
-// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%TwoTypes, (constants.%DefaultOrUnformed.impl_witness.679) [concrete = constants.%DefaultOrUnformed.facet]
+// CHECK:STDOUT:   %DefaultOrUnformed.facet: %DefaultOrUnformed.type = facet_value constants.%TwoTypes, (constants.%DefaultOrUnformed.impl_witness.fcc) [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %.loc7_32.1: %DefaultOrUnformed.type = converted constants.%TwoTypes, %DefaultOrUnformed.facet [concrete = constants.%DefaultOrUnformed.facet]
 // CHECK:STDOUT:   %as_type: type = facet_access_type %.loc7_32.1 [concrete = constants.%TwoTypes]
 // CHECK:STDOUT:   %.loc7_32.2: type = converted %.loc7_32.1, %as_type [concrete = constants.%TwoTypes]
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT:   %.loc7_1: ref %TwoTypes = splice_block file.%x.var [concrete = file.%x.var] {}
-// CHECK:STDOUT:   %T.as.DefaultOrUnformed.impl.Op.call: init %TwoTypes to %.loc7_1 = call %T.as.DefaultOrUnformed.impl.Op.specific_fn()
-// CHECK:STDOUT:   assign file.%x.var, %T.as.DefaultOrUnformed.impl.Op.call
+// CHECK:STDOUT:   %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call: init %TwoTypes to %.loc7_1 = call %T.binding.as_type.as.DefaultOrUnformed.impl.Op.specific_fn()
+// CHECK:STDOUT:   assign file.%x.var, %T.binding.as_type.as.DefaultOrUnformed.impl.Op.call
 // CHECK:STDOUT:   <elided>
 // CHECK:STDOUT: }
 // CHECK:STDOUT: