Store an `InstId` instead of a `TypeId` in `UnboundElementType`. (#5260)

This gives a slightly simpler representation for `UnboundElementType`s
in eval blocks, and in principle allows us to preserve the spelling of a
field's type into the `UnboundElementType` and thereby into a field
reference, although as of right now this doesn't affect our diagnostic
output in any way.

During error recovery for a field with a non-concrete type, preserve the
type in the `UnboundElementType` regardless. It's not really problematic
to have a non-concrete type there, and this makes it easier to track the
instruction used to specify the type.

This is a step towards switching symbolic types to always be abstract
during type checking.

toolchain/check/handle_binding_pattern.cpp

@@ -16,6 +16,7 @@
 #include "toolchain/sem_ir/ids.h"
 #include "toolchain/sem_ir/inst.h"
 #include "toolchain/sem_ir/pattern.h"
+#include "toolchain/sem_ir/typed_insts.h"
 
 namespace Carbon::Check {
 
@@ -141,11 +142,15 @@ static auto HandleAnyBindingPattern(Context& context, Parse::NodeId node_id,
           return context.emitter().Build(type_node, AbstractTypeInFieldDecl,
                                          cast_type_id);
         });
+    if (cast_type_id == SemIR::ErrorInst::SingletonTypeId) {
+      cast_type_inst_id = SemIR::ErrorInst::SingletonInstId;
+    }
     auto binding_id =
         context.parse_tree().As<Parse::VarBindingPatternId>(node_id);
     auto& class_info = context.classes().Get(parent_class_decl->class_id);
-    auto field_type_id =
-        GetUnboundElementType(context, class_info.self_type_id, cast_type_id);
+    auto field_type_id = GetUnboundElementType(
+        context, context.types().GetInstId(class_info.self_type_id),
+        cast_type_inst_id);
     auto field_id =
         AddInst<SemIR::FieldDecl>(context, binding_id,
                                   {.type_id = field_type_id,

toolchain/check/handle_class.cpp

@@ -545,8 +545,9 @@ auto HandleParseNode(Context& context, Parse::BaseDeclId node_id) -> bool {
 
   // The `base` value in the class scope has an unbound element type. Instance
   // binding will be performed when it's found by name lookup into an instance.
-  auto field_type_id = GetUnboundElementType(context, class_info.self_type_id,
-                                             base_info.type_id);
+  auto field_type_id = GetUnboundElementType(
+      context, context.types().GetInstId(class_info.self_type_id),
+      base_info.inst_id);
   class_info.base_id =
       AddInst<SemIR::BaseDecl>(context, node_id,
                                {.type_id = field_type_id,
@@ -658,7 +659,8 @@ static auto AddStructTypeFields(
             field_decl.type_id);
     struct_type_fields.push_back(
         {.name_id = field_decl.name_id,
-         .type_id = unbound_element_type.element_type_id});
+         .type_id = context.types().GetTypeIdForTypeInstId(
+             unbound_element_type.element_type_inst_id)});
   }
   auto fields_id =
       context.struct_type_fields().AddCanonical(struct_type_fields);

toolchain/check/import_ref.cpp

@@ -2823,21 +2823,18 @@ static auto TryResolveTypedInst(ImportRefResolver& resolver,
                                 SemIR::UnboundElementType inst)
     -> ResolveResult {
   CARBON_CHECK(inst.type_id == SemIR::TypeType::SingletonTypeId);
-  auto class_const_id = GetLocalConstantId(resolver, inst.class_type_id);
-  auto elem_const_id = GetLocalConstantId(resolver, inst.element_type_id);
+  auto class_const_inst_id =
+      GetLocalConstantInstId(resolver, inst.class_type_inst_id);
+  auto elem_const_inst_id =
+      GetLocalConstantInstId(resolver, inst.element_type_inst_id);
   if (resolver.HasNewWork()) {
     return ResolveResult::Retry();
   }
 
   return ResolveAs<SemIR::UnboundElementType>(
-      resolver,
-      {.type_id = SemIR::TypeType::SingletonTypeId,
-       .class_type_id =
-           resolver.local_context().types().GetTypeIdForTypeConstantId(
-               class_const_id),
-       .element_type_id =
-           resolver.local_context().types().GetTypeIdForTypeConstantId(
-               elem_const_id)});
+      resolver, {.type_id = SemIR::TypeType::SingletonTypeId,
+                 .class_type_inst_id = class_const_inst_id,
+                 .element_type_inst_id = elem_const_inst_id});
 }
 
 // Tries to resolve the InstId, returning a canonical constant when ready, or

toolchain/check/member_access.cpp

@@ -384,8 +384,10 @@ static auto PerformInstanceBinding(Context& context, SemIR::LocId loc_id,
           context.types().TryGetAs<SemIR::UnboundElementType>(
               context.insts().Get(member_id).type_id())) {
     // Convert the base to the type of the element if necessary.
-    base_id = ConvertToValueOrRefOfType(context, loc_id, base_id,
-                                        unbound_element_type->class_type_id);
+    base_id = ConvertToValueOrRefOfType(
+        context, loc_id, base_id,
+        context.types().GetTypeIdForTypeInstId(
+            unbound_element_type->class_type_inst_id));
 
     // Find the specified element, which could be either a field or a base
     // class, and build an element access expression.
@@ -396,7 +398,8 @@ static auto PerformInstanceBinding(Context& context, SemIR::LocId loc_id,
     auto index = GetClassElementIndex(context, element_id);
     auto access_id = GetOrAddInst<SemIR::ClassElementAccess>(
         context, loc_id,
-        {.type_id = unbound_element_type->element_type_id,
+        {.type_id = context.types().GetTypeIdForTypeInstId(
+             unbound_element_type->element_type_inst_id),
          .base_id = base_id,
          .index = index});
     if (SemIR::GetExprCategory(context.sem_ir(), base_id) ==

toolchain/check/testdata/class/fail_generic_method.carbon

@@ -101,7 +101,7 @@ fn Class(N:! i32).F[self: Self](n: T) {}
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @Class.%T.loc11_13.2 (%T) [symbolic = %require_complete (constants.%require_complete.4ae)]
 // CHECK:STDOUT:   %Class: type = class_type @Class, @Class(%T.loc11_13.2) [symbolic = %Class (constants.%Class)]
-// CHECK:STDOUT:   %Class.elem: type = unbound_element_type @Class.%Class (%Class), @Class.%T.loc11_13.2 (%T) [symbolic = %Class.elem (constants.%Class.elem)]
+// CHECK:STDOUT:   %Class.elem: type = unbound_element_type %Class, %T.loc11_13.2 [symbolic = %Class.elem (constants.%Class.elem)]
 // CHECK:STDOUT:   %F.type: type = fn_type @F.1, @Class(%T.loc11_13.2) [symbolic = %F.type (constants.%F.type.6d6)]
 // CHECK:STDOUT:   %F: @Class.%F.type (%F.type.6d6) = struct_value () [symbolic = %F (constants.%F.cca)]
 // CHECK:STDOUT:   %struct_type.a: type = struct_type {.a: @Class.%T.loc11_13.2 (%T)} [symbolic = %struct_type.a (constants.%struct_type.a)]

toolchain/check/testdata/class/generic/adapt.carbon

@@ -191,7 +191,7 @@ fn ImportedConvertLocal(a: Adapter(C)) -> i32 {
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @C.%T.loc4_9.2 (%T) [symbolic = %require_complete (constants.%require_complete.4ae)]
 // CHECK:STDOUT:   %C: type = class_type @C, @C(%T.loc4_9.2) [symbolic = %C (constants.%C.f2e)]
-// CHECK:STDOUT:   %C.elem: type = unbound_element_type @C.%C (%C.f2e), @C.%T.loc4_9.2 (%T) [symbolic = %C.elem (constants.%C.elem.66c)]
+// CHECK:STDOUT:   %C.elem: type = unbound_element_type %C, %T.loc4_9.2 [symbolic = %C.elem (constants.%C.elem.66c)]
 // CHECK:STDOUT:   %struct_type.x: type = struct_type {.x: @C.%T.loc4_9.2 (%T)} [symbolic = %struct_type.x (constants.%struct_type.x.2ac)]
 // CHECK:STDOUT:   %complete_type.loc6_1.2: <witness> = complete_type_witness @C.%struct_type.x (%struct_type.x.2ac) [symbolic = %complete_type.loc6_1.2 (constants.%complete_type.433)]
 // CHECK:STDOUT:
@@ -341,7 +341,7 @@ fn ImportedConvertLocal(a: Adapter(C)) -> i32 {
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @C.%T (%T) [symbolic = %require_complete (constants.%require_complete.4ae)]
 // CHECK:STDOUT:   %C: type = class_type @C, @C(%T) [symbolic = %C (constants.%C.f2e)]
-// CHECK:STDOUT:   %C.elem: type = unbound_element_type @C.%C (%C.f2e), @C.%T (%T) [symbolic = %C.elem (constants.%C.elem.66c)]
+// CHECK:STDOUT:   %C.elem: type = unbound_element_type %C, %T [symbolic = %C.elem (constants.%C.elem.66c)]
 // CHECK:STDOUT:   %struct_type.x: type = struct_type {.x: @C.%T (%T)} [symbolic = %struct_type.x (constants.%struct_type.x.2ac)]
 // CHECK:STDOUT:   %complete_type: <witness> = complete_type_witness @C.%struct_type.x (%struct_type.x.2ac) [symbolic = %complete_type (constants.%complete_type.433)]
 // CHECK:STDOUT:
@@ -459,7 +459,7 @@ fn ImportedConvertLocal(a: Adapter(C)) -> i32 {
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @C.%T.loc4_9.2 (%T) [symbolic = %require_complete (constants.%require_complete.4ae)]
 // CHECK:STDOUT:   %C: type = class_type @C, @C(%T.loc4_9.2) [symbolic = %C (constants.%C.f2e)]
-// CHECK:STDOUT:   %C.elem: type = unbound_element_type @C.%C (%C.f2e), @C.%T.loc4_9.2 (%T) [symbolic = %C.elem (constants.%C.elem.66c)]
+// CHECK:STDOUT:   %C.elem: type = unbound_element_type %C, %T.loc4_9.2 [symbolic = %C.elem (constants.%C.elem.66c)]
 // CHECK:STDOUT:   %struct_type.x: type = struct_type {.x: @C.%T.loc4_9.2 (%T)} [symbolic = %struct_type.x (constants.%struct_type.x.2ac)]
 // CHECK:STDOUT:   %complete_type.loc6_1.2: <witness> = complete_type_witness @C.%struct_type.x (%struct_type.x.2ac) [symbolic = %complete_type.loc6_1.2 (constants.%complete_type.433)]
 // CHECK:STDOUT:
@@ -576,7 +576,7 @@ fn ImportedConvertLocal(a: Adapter(C)) -> i32 {
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @C.%T.loc7_9.2 (%T) [symbolic = %require_complete (constants.%require_complete.4ae)]
 // CHECK:STDOUT:   %C: type = class_type @C, @C(%T.loc7_9.2) [symbolic = %C (constants.%C.f2e)]
-// CHECK:STDOUT:   %C.elem: type = unbound_element_type @C.%C (%C.f2e), @C.%T.loc7_9.2 (%T) [symbolic = %C.elem (constants.%C.elem.66c)]
+// CHECK:STDOUT:   %C.elem: type = unbound_element_type %C, %T.loc7_9.2 [symbolic = %C.elem (constants.%C.elem.66c)]
 // CHECK:STDOUT:   %struct_type.x: type = struct_type {.x: @C.%T.loc7_9.2 (%T)} [symbolic = %struct_type.x (constants.%struct_type.x.2ac)]
 // CHECK:STDOUT:   %complete_type.loc9_1.2: <witness> = complete_type_witness @C.%struct_type.x (%struct_type.x.2ac) [symbolic = %complete_type.loc9_1.2 (constants.%complete_type.433)]
 // CHECK:STDOUT:
@@ -712,7 +712,7 @@ fn ImportedConvertLocal(a: Adapter(C)) -> i32 {
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @C.%T (%T) [symbolic = %require_complete (constants.%require_complete.4ae)]
 // CHECK:STDOUT:   %C: type = class_type @C, @C(%T) [symbolic = %C (constants.%C.f2e)]
-// CHECK:STDOUT:   %C.elem: type = unbound_element_type @C.%C (%C.f2e), @C.%T (%T) [symbolic = %C.elem (constants.%C.elem.66c)]
+// CHECK:STDOUT:   %C.elem: type = unbound_element_type %C, %T [symbolic = %C.elem (constants.%C.elem.66c)]
 // CHECK:STDOUT:   %struct_type.x: type = struct_type {.x: @C.%T (%T)} [symbolic = %struct_type.x (constants.%struct_type.x.2ac)]
 // CHECK:STDOUT:   %complete_type: <witness> = complete_type_witness @C.%struct_type.x (%struct_type.x.2ac) [symbolic = %complete_type (constants.%complete_type.433)]
 // CHECK:STDOUT:

toolchain/check/testdata/class/generic/base_is_generic.carbon

@@ -162,7 +162,7 @@ fn H() {
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @Base.%T.loc4_17.2 (%T) [symbolic = %require_complete (constants.%require_complete.4ae)]
 // CHECK:STDOUT:   %Base: type = class_type @Base, @Base(%T.loc4_17.2) [symbolic = %Base (constants.%Base.370)]
-// CHECK:STDOUT:   %Base.elem: type = unbound_element_type @Base.%Base (%Base.370), @Base.%T.loc4_17.2 (%T) [symbolic = %Base.elem (constants.%Base.elem.9af)]
+// CHECK:STDOUT:   %Base.elem: type = unbound_element_type %Base, %T.loc4_17.2 [symbolic = %Base.elem (constants.%Base.elem.9af)]
 // CHECK:STDOUT:   %struct_type.x: type = struct_type {.x: @Base.%T.loc4_17.2 (%T)} [symbolic = %struct_type.x (constants.%struct_type.x.2ac)]
 // CHECK:STDOUT:   %complete_type.loc6_1.2: <witness> = complete_type_witness @Base.%struct_type.x (%struct_type.x.2ac) [symbolic = %complete_type.loc6_1.2 (constants.%complete_type.433)]
 // CHECK:STDOUT:
@@ -347,7 +347,7 @@ fn H() {
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @Base.%T (%T) [symbolic = %require_complete (constants.%require_complete.4ae)]
 // CHECK:STDOUT:   %Base: type = class_type @Base, @Base(%T) [symbolic = %Base (constants.%Base.370)]
-// CHECK:STDOUT:   %Base.elem: type = unbound_element_type @Base.%Base (%Base.370), @Base.%T (%T) [symbolic = %Base.elem (constants.%Base.elem.9af)]
+// CHECK:STDOUT:   %Base.elem: type = unbound_element_type %Base, %T [symbolic = %Base.elem (constants.%Base.elem.9af)]
 // CHECK:STDOUT:   %struct_type.x: type = struct_type {.x: @Base.%T (%T)} [symbolic = %struct_type.x (constants.%struct_type.x.2ac)]
 // CHECK:STDOUT:   %complete_type: <witness> = complete_type_witness @Base.%struct_type.x (%struct_type.x.2ac) [symbolic = %complete_type (constants.%complete_type.433)]
 // CHECK:STDOUT:
@@ -600,7 +600,7 @@ fn H() {
 // CHECK:STDOUT:   %X.loc9_19.2: type = class_type @X, @X(%T.loc8_9.2) [symbolic = %X.loc9_19.2 (constants.%X.75b6d8.2)]
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @C.%X.loc9_19.2 (%X.75b6d8.2) [symbolic = %require_complete (constants.%require_complete.441)]
 // CHECK:STDOUT:   %C: type = class_type @C, @C(%T.loc8_9.2) [symbolic = %C (constants.%C.f2e)]
-// CHECK:STDOUT:   %C.elem: type = unbound_element_type @C.%C (%C.f2e), @C.%X.loc9_19.2 (%X.75b6d8.2) [symbolic = %C.elem (constants.%C.elem.3f4)]
+// CHECK:STDOUT:   %C.elem: type = unbound_element_type %C, %X.loc9_19.2 [symbolic = %C.elem (constants.%C.elem.3f4)]
 // CHECK:STDOUT:   %struct_type.base: type = struct_type {.base: @C.%X.loc9_19.2 (%X.75b6d8.2)} [symbolic = %struct_type.base (constants.%struct_type.base.f5f)]
 // CHECK:STDOUT:   %complete_type.loc10_1.2: <witness> = complete_type_witness @C.%struct_type.base (%struct_type.base.f5f) [symbolic = %complete_type.loc10_1.2 (constants.%complete_type.768)]
 // CHECK:STDOUT:
@@ -822,7 +822,7 @@ fn H() {
 // CHECK:STDOUT:   %X: type = class_type @X, @X(%T) [symbolic = %X (constants.%X.75b6d8.2)]
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @C.%X (%X.75b6d8.2) [symbolic = %require_complete (constants.%require_complete.441)]
 // CHECK:STDOUT:   %C: type = class_type @C, @C(%T) [symbolic = %C (constants.%C.f2e)]
-// CHECK:STDOUT:   %C.elem: type = unbound_element_type @C.%C (%C.f2e), @C.%X (%X.75b6d8.2) [symbolic = %C.elem (constants.%C.elem.3f4)]
+// CHECK:STDOUT:   %C.elem: type = unbound_element_type %C, %X [symbolic = %C.elem (constants.%C.elem.3f4)]
 // CHECK:STDOUT:   %struct_type.base: type = struct_type {.base: @C.%X (%X.75b6d8.2)} [symbolic = %struct_type.base (constants.%struct_type.base.f5f)]
 // CHECK:STDOUT:   %complete_type: <witness> = complete_type_witness @C.%struct_type.base (%struct_type.base.f5f) [symbolic = %complete_type (constants.%complete_type.768)]
 // CHECK:STDOUT:

toolchain/check/testdata/class/generic/basic.carbon

@@ -85,7 +85,7 @@ class Declaration(T:! type);
 // CHECK:STDOUT:   %GetValue: @Class.%GetValue.type (%GetValue.type) = struct_value () [symbolic = %GetValue (constants.%GetValue)]
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @Class.%T.loc11_13.2 (%T) [symbolic = %require_complete (constants.%require_complete.4ae)]
 // CHECK:STDOUT:   %Class: type = class_type @Class, @Class(%T.loc11_13.2) [symbolic = %Class (constants.%Class)]
-// CHECK:STDOUT:   %Class.elem: type = unbound_element_type @Class.%Class (%Class), @Class.%T.loc11_13.2 (%T) [symbolic = %Class.elem (constants.%Class.elem)]
+// CHECK:STDOUT:   %Class.elem: type = unbound_element_type %Class, %T.loc11_13.2 [symbolic = %Class.elem (constants.%Class.elem)]
 // CHECK:STDOUT:   %struct_type.k: type = struct_type {.k: @Class.%T.loc11_13.2 (%T)} [symbolic = %struct_type.k (constants.%struct_type.k)]
 // CHECK:STDOUT:   %complete_type.loc22_1.2: <witness> = complete_type_witness @Class.%struct_type.k (%struct_type.k) [symbolic = %complete_type.loc22_1.2 (constants.%complete_type)]
 // CHECK:STDOUT:
@@ -159,7 +159,7 @@ class Declaration(T:! type);
 // CHECK:STDOUT:   %require_complete.loc12_34: <witness> = require_complete_type @GetAddr.%ptr.loc12_38.1 (%ptr.79f) [symbolic = %require_complete.loc12_34 (constants.%require_complete.6e5)]
 // CHECK:STDOUT:   %require_complete.loc12_23: <witness> = require_complete_type @GetAddr.%ptr.loc12_29.1 (%ptr.955) [symbolic = %require_complete.loc12_23 (constants.%require_complete.2ae)]
 // CHECK:STDOUT:   %require_complete.loc13: <witness> = require_complete_type @GetAddr.%Class (%Class) [symbolic = %require_complete.loc13 (constants.%require_complete.4f8)]
-// CHECK:STDOUT:   %Class.elem: type = unbound_element_type @GetAddr.%Class (%Class), @GetAddr.%T (%T) [symbolic = %Class.elem (constants.%Class.elem)]
+// CHECK:STDOUT:   %Class.elem: type = unbound_element_type %Class, %T [symbolic = %Class.elem (constants.%Class.elem)]
 // CHECK:STDOUT:
 // CHECK:STDOUT:   fn[addr %self.param_patt: @GetAddr.%ptr.loc12_29.1 (%ptr.955)]() -> @GetAddr.%ptr.loc12_38.1 (%ptr.79f) {
 // CHECK:STDOUT:   !entry:
@@ -178,7 +178,7 @@ class Declaration(T:! type);
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete.loc17: <witness> = require_complete_type @GetValue.%Class (%Class) [symbolic = %require_complete.loc17 (constants.%require_complete.4f8)]
-// CHECK:STDOUT:   %Class.elem: type = unbound_element_type @GetValue.%Class (%Class), @GetValue.%T (%T) [symbolic = %Class.elem (constants.%Class.elem)]
+// CHECK:STDOUT:   %Class.elem: type = unbound_element_type %Class, %T [symbolic = %Class.elem (constants.%Class.elem)]
 // CHECK:STDOUT:   %require_complete.loc18: <witness> = require_complete_type @GetValue.%T (%T) [symbolic = %require_complete.loc18 (constants.%require_complete.4ae)]
 // CHECK:STDOUT:
 // CHECK:STDOUT:   fn[%self.param_patt: @GetValue.%Class (%Class)]() -> @GetValue.%T (%T) {

toolchain/check/testdata/class/generic/complete_in_conversion.carbon

@@ -168,13 +168,13 @@ fn F(a: A(0)*) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %A: type = class_type @A, @A(%N.loc6_9.2) [symbolic = %A (constants.%A.dd3)]
-// CHECK:STDOUT:   %A.elem.loc7: type = unbound_element_type @A.%A (%A.dd3), %B [symbolic = %A.elem.loc7 (constants.%A.elem.500)]
+// CHECK:STDOUT:   %A.elem.loc7: type = unbound_element_type %A, constants.%B [symbolic = %A.elem.loc7 (constants.%A.elem.500)]
 // CHECK:STDOUT:   %Convert.bound: <bound method> = bound_method %N.loc6_9.2, constants.%Convert.960 [symbolic = %Convert.bound (constants.%Convert.bound.588)]
 // CHECK:STDOUT:   %bound_method: <bound method> = bound_method %N.loc6_9.2, constants.%Convert.specific_fn.8a8 [symbolic = %bound_method (constants.%bound_method.f9c)]
 // CHECK:STDOUT:   %int.convert_checked: init Core.IntLiteral = call %bound_method(%N.loc6_9.2) [symbolic = %int.convert_checked (constants.%int.convert_checked)]
 // CHECK:STDOUT:   %iN.builtin: type = int_type signed, %int.convert_checked [symbolic = %iN.builtin (constants.%iN.builtin.8fe)]
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @A.%iN.builtin (%iN.builtin.8fe) [symbolic = %require_complete (constants.%require_complete.e34)]
-// CHECK:STDOUT:   %A.elem.loc12: type = unbound_element_type @A.%A (%A.dd3), @A.%iN.builtin (%iN.builtin.8fe) [symbolic = %A.elem.loc12 (constants.%A.elem.07f)]
+// CHECK:STDOUT:   %A.elem.loc12: type = unbound_element_type %A, %iN.builtin [symbolic = %A.elem.loc12 (constants.%A.elem.07f)]
 // CHECK:STDOUT:   %struct_type.base.n: type = struct_type {.base: %B, .n: @A.%iN.builtin (%iN.builtin.8fe)} [symbolic = %struct_type.base.n (constants.%struct_type.base.n)]
 // CHECK:STDOUT:   %complete_type.loc13_1.2: <witness> = complete_type_witness @A.%struct_type.base.n (%struct_type.base.n) [symbolic = %complete_type.loc13_1.2 (constants.%complete_type.beb)]
 // CHECK:STDOUT:

toolchain/check/testdata/class/generic/field.carbon

@@ -149,7 +149,7 @@ fn H(U:! type, c: Class(U)) -> U {
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @Class.%T.loc11_13.2 (%T) [symbolic = %require_complete (constants.%require_complete.4aeca8.1)]
 // CHECK:STDOUT:   %Class: type = class_type @Class, @Class(%T.loc11_13.2) [symbolic = %Class (constants.%Class.fe1b2d.1)]
-// CHECK:STDOUT:   %Class.elem: type = unbound_element_type @Class.%Class (%Class.fe1b2d.1), @Class.%T.loc11_13.2 (%T) [symbolic = %Class.elem (constants.%Class.elem.e262de.1)]
+// CHECK:STDOUT:   %Class.elem: type = unbound_element_type %Class, %T.loc11_13.2 [symbolic = %Class.elem (constants.%Class.elem.e262de.1)]
 // CHECK:STDOUT:   %struct_type.x: type = struct_type {.x: @Class.%T.loc11_13.2 (%T)} [symbolic = %struct_type.x (constants.%struct_type.x.2ac3f0.1)]
 // CHECK:STDOUT:   %complete_type.loc13_1.2: <witness> = complete_type_witness @Class.%struct_type.x (%struct_type.x.2ac3f0.1) [symbolic = %complete_type.loc13_1.2 (constants.%complete_type.4339b3.1)]
 // CHECK:STDOUT:
@@ -185,7 +185,7 @@ fn H(U:! type, c: Class(U)) -> U {
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete.loc19: <witness> = require_complete_type @G.%Class.loc19_26.2 (%Class.fe1b2d.1) [symbolic = %require_complete.loc19 (constants.%require_complete.4f8a42.1)]
-// CHECK:STDOUT:   %Class.elem: type = unbound_element_type @G.%Class.loc19_26.2 (%Class.fe1b2d.1), @G.%T.loc19_6.2 (%T) [symbolic = %Class.elem (constants.%Class.elem.e262de.1)]
+// CHECK:STDOUT:   %Class.elem: type = unbound_element_type %Class.loc19_26.2, %T.loc19_6.2 [symbolic = %Class.elem (constants.%Class.elem.e262de.1)]
 // CHECK:STDOUT:   %require_complete.loc20: <witness> = require_complete_type @G.%T.loc19_6.2 (%T) [symbolic = %require_complete.loc20 (constants.%require_complete.4aeca8.1)]
 // CHECK:STDOUT:
 // CHECK:STDOUT:   fn(%T.patt.loc19_6.1: type, %c.param_patt: @G.%Class.loc19_26.2 (%Class.fe1b2d.1)) -> @G.%T.loc19_6.2 (%T) {
@@ -206,7 +206,7 @@ fn H(U:! type, c: Class(U)) -> U {
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete.loc23_29: <witness> = require_complete_type @H.%U.loc23_6.2 (%U) [symbolic = %require_complete.loc23_29 (constants.%require_complete.4aeca8.2)]
 // CHECK:STDOUT:   %require_complete.loc23_17: <witness> = require_complete_type @H.%Class.loc23_26.2 (%Class.fe1b2d.2) [symbolic = %require_complete.loc23_17 (constants.%require_complete.4f8a42.2)]
-// CHECK:STDOUT:   %Class.elem: type = unbound_element_type @H.%Class.loc23_26.2 (%Class.fe1b2d.2), @H.%U.loc23_6.2 (%U) [symbolic = %Class.elem (constants.%Class.elem.e262de.2)]
+// CHECK:STDOUT:   %Class.elem: type = unbound_element_type %Class.loc23_26.2, %U.loc23_6.2 [symbolic = %Class.elem (constants.%Class.elem.e262de.2)]
 // CHECK:STDOUT:
 // CHECK:STDOUT:   fn(%U.patt.loc23_6.1: type, %c.param_patt: @H.%Class.loc23_26.2 (%Class.fe1b2d.2)) -> @H.%U.loc23_6.2 (%U) {
 // CHECK:STDOUT:   !entry:

toolchain/check/testdata/class/generic/import.carbon

@@ -172,7 +172,7 @@ class Class(U:! type) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %CompleteClass: type = class_type @CompleteClass, @CompleteClass(%T.loc6_21.2) [symbolic = %CompleteClass (constants.%CompleteClass.f97)]
-// CHECK:STDOUT:   %CompleteClass.elem: type = unbound_element_type @CompleteClass.%CompleteClass (%CompleteClass.f97), %i32 [symbolic = %CompleteClass.elem (constants.%CompleteClass.elem)]
+// CHECK:STDOUT:   %CompleteClass.elem: type = unbound_element_type %CompleteClass, constants.%i32 [symbolic = %CompleteClass.elem (constants.%CompleteClass.elem)]
 // CHECK:STDOUT:   %F.type: type = fn_type @F.1, @CompleteClass(%T.loc6_21.2) [symbolic = %F.type (constants.%F.type.14f)]
 // CHECK:STDOUT:   %F: @CompleteClass.%F.type (%F.type.14f) = struct_value () [symbolic = %F (constants.%F.874)]
 // CHECK:STDOUT:
@@ -341,7 +341,7 @@ class Class(U:! type) {
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @Class.%T.1 (%T) [symbolic = %require_complete (constants.%require_complete.4ae)]
 // CHECK:STDOUT:   %Class: type = class_type @Class, @Class(%T.1) [symbolic = %Class (constants.%Class)]
-// CHECK:STDOUT:   %Class.elem: type = unbound_element_type @Class.%Class (%Class), @Class.%T.1 (%T) [symbolic = %Class.elem (constants.%Class.elem)]
+// CHECK:STDOUT:   %Class.elem: type = unbound_element_type %Class, %T.1 [symbolic = %Class.elem (constants.%Class.elem)]
 // CHECK:STDOUT:   %struct_type.x: type = struct_type {.x: @Class.%T.1 (%T)} [symbolic = %struct_type.x (constants.%struct_type.x)]
 // CHECK:STDOUT:   %complete_type.loc6_1.2: <witness> = complete_type_witness @Class.%struct_type.x (%struct_type.x) [symbolic = %complete_type.loc6_1.2 (constants.%complete_type.433)]
 // CHECK:STDOUT:
@@ -367,7 +367,7 @@ class Class(U:! type) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %CompleteClass: type = class_type @CompleteClass, @CompleteClass(%T) [symbolic = %CompleteClass (constants.%CompleteClass.f97)]
-// CHECK:STDOUT:   %CompleteClass.elem: type = unbound_element_type @CompleteClass.%CompleteClass (%CompleteClass.f97), %i32 [symbolic = %CompleteClass.elem (constants.%CompleteClass.elem.9ef)]
+// CHECK:STDOUT:   %CompleteClass.elem: type = unbound_element_type %CompleteClass, constants.%i32 [symbolic = %CompleteClass.elem (constants.%CompleteClass.elem.9ef)]
 // CHECK:STDOUT:   %F.type: type = fn_type @F.1, @CompleteClass(%T) [symbolic = %F.type (constants.%F.type.14f)]
 // CHECK:STDOUT:   %F: @CompleteClass.%F.type (%F.type.14f) = struct_value () [symbolic = %F (constants.%F.874)]
 // CHECK:STDOUT:
@@ -519,7 +519,7 @@ class Class(U:! type) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %CompleteClass: type = class_type @CompleteClass, @CompleteClass(%T) [symbolic = %CompleteClass (constants.%CompleteClass.f97)]
-// CHECK:STDOUT:   %CompleteClass.elem: type = unbound_element_type @CompleteClass.%CompleteClass (%CompleteClass.f97), %i32 [symbolic = %CompleteClass.elem (constants.%CompleteClass.elem.28a)]
+// CHECK:STDOUT:   %CompleteClass.elem: type = unbound_element_type %CompleteClass, constants.%i32 [symbolic = %CompleteClass.elem (constants.%CompleteClass.elem.28a)]
 // CHECK:STDOUT:   %F.type: type = fn_type @F.1, @CompleteClass(%T) [symbolic = %F.type (constants.%F.type.14f)]
 // CHECK:STDOUT:   %F: @CompleteClass.%F.type (%F.type.14f) = struct_value () [symbolic = %F (constants.%F.874)]
 // CHECK:STDOUT:
@@ -691,7 +691,7 @@ class Class(U:! type) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %CompleteClass: type = class_type @CompleteClass, @CompleteClass(%T) [symbolic = %CompleteClass (constants.%CompleteClass.f97)]
-// CHECK:STDOUT:   %CompleteClass.elem: type = unbound_element_type @CompleteClass.%CompleteClass (%CompleteClass.f97), %i32 [symbolic = %CompleteClass.elem (constants.%CompleteClass.elem.9ef)]
+// CHECK:STDOUT:   %CompleteClass.elem: type = unbound_element_type %CompleteClass, constants.%i32 [symbolic = %CompleteClass.elem (constants.%CompleteClass.elem.9ef)]
 // CHECK:STDOUT:   %F.type: type = fn_type @F.1, @CompleteClass(%T) [symbolic = %F.type (constants.%F.type.14f)]
 // CHECK:STDOUT:   %F: @CompleteClass.%F.type (%F.type.14f) = struct_value () [symbolic = %F (constants.%F.874)]
 // CHECK:STDOUT:

toolchain/check/testdata/class/generic/init.carbon

@@ -131,7 +131,7 @@ fn InitFromAdaptedSpecific(x: i32) -> i32 {
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @Class.%T.loc4_13.2 (%T) [symbolic = %require_complete (constants.%require_complete.4ae)]
 // CHECK:STDOUT:   %Class: type = class_type @Class, @Class(%T.loc4_13.2) [symbolic = %Class (constants.%Class.fe1)]
-// CHECK:STDOUT:   %Class.elem: type = unbound_element_type @Class.%Class (%Class.fe1), @Class.%T.loc4_13.2 (%T) [symbolic = %Class.elem (constants.%Class.elem.e26)]
+// CHECK:STDOUT:   %Class.elem: type = unbound_element_type %Class, %T.loc4_13.2 [symbolic = %Class.elem (constants.%Class.elem.e26)]
 // CHECK:STDOUT:   %struct_type.k: type = struct_type {.k: @Class.%T.loc4_13.2 (%T)} [symbolic = %struct_type.k (constants.%struct_type.k.b21)]
 // CHECK:STDOUT:   %complete_type.loc6_1.2: <witness> = complete_type_witness @Class.%struct_type.k (%struct_type.k.b21) [symbolic = %complete_type.loc6_1.2 (constants.%complete_type.b9e)]
 // CHECK:STDOUT:
@@ -160,7 +160,7 @@ fn InitFromAdaptedSpecific(x: i32) -> i32 {
 // CHECK:STDOUT:   %Class.loc9_17.2: type = class_type @Class, @Class(%T.loc8_26.2) [symbolic = %Class.loc9_17.2 (constants.%Class.fe1)]
 // CHECK:STDOUT:   %require_complete.loc9: <witness> = require_complete_type @InitFromStructGeneric.%Class.loc9_17.2 (%Class.fe1) [symbolic = %require_complete.loc9 (constants.%require_complete.4f8)]
 // CHECK:STDOUT:   %struct_type.k: type = struct_type {.k: @InitFromStructGeneric.%T.loc8_26.2 (%T)} [symbolic = %struct_type.k (constants.%struct_type.k.b21)]
-// CHECK:STDOUT:   %Class.elem: type = unbound_element_type @InitFromStructGeneric.%Class.loc9_17.2 (%Class.fe1), @InitFromStructGeneric.%T.loc8_26.2 (%T) [symbolic = %Class.elem (constants.%Class.elem.e26)]
+// CHECK:STDOUT:   %Class.elem: type = unbound_element_type %Class.loc9_17.2, %T.loc8_26.2 [symbolic = %Class.elem (constants.%Class.elem.e26)]
 // CHECK:STDOUT:
 // CHECK:STDOUT:   fn(%T.patt.loc8_26.1: type, %x.param_patt: @InitFromStructGeneric.%T.loc8_26.2 (%T)) -> @InitFromStructGeneric.%T.loc8_26.2 (%T) {
 // CHECK:STDOUT:   !entry:

toolchain/check/testdata/class/generic/member_access.carbon

@@ -185,7 +185,7 @@ fn StaticMemberFunctionCall(T:! type) -> Class(T) {
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @Class.%T.loc2_13.2 (%T) [symbolic = %require_complete (constants.%require_complete.4ae)]
 // CHECK:STDOUT:   %Class: type = class_type @Class, @Class(%T.loc2_13.2) [symbolic = %Class (constants.%Class.fe1)]
-// CHECK:STDOUT:   %Class.elem: type = unbound_element_type @Class.%Class (%Class.fe1), @Class.%T.loc2_13.2 (%T) [symbolic = %Class.elem (constants.%Class.elem.e26)]
+// CHECK:STDOUT:   %Class.elem: type = unbound_element_type %Class, %T.loc2_13.2 [symbolic = %Class.elem (constants.%Class.elem.e26)]
 // CHECK:STDOUT:   %Get.type: type = fn_type @Get, @Class(%T.loc2_13.2) [symbolic = %Get.type (constants.%Get.type.fd9)]
 // CHECK:STDOUT:   %Get: @Class.%Get.type (%Get.type.fd9) = struct_value () [symbolic = %Get (constants.%Get.cf9)]
 // CHECK:STDOUT:   %GetAddr.type: type = fn_type @GetAddr, @Class(%T.loc2_13.2) [symbolic = %GetAddr.type (constants.%GetAddr.type.402)]
@@ -252,7 +252,7 @@ fn StaticMemberFunctionCall(T:! type) -> Class(T) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete.loc5_14: <witness> = require_complete_type @Get.%Class (%Class.fe1) [symbolic = %require_complete.loc5_14 (constants.%require_complete.4f8)]
-// CHECK:STDOUT:   %Class.elem: type = unbound_element_type @Get.%Class (%Class.fe1), @Get.%T (%T) [symbolic = %Class.elem (constants.%Class.elem.e26)]
+// CHECK:STDOUT:   %Class.elem: type = unbound_element_type %Class, %T [symbolic = %Class.elem (constants.%Class.elem.e26)]
 // CHECK:STDOUT:   %require_complete.loc5_42: <witness> = require_complete_type @Get.%T (%T) [symbolic = %require_complete.loc5_42 (constants.%require_complete.4ae)]
 // CHECK:STDOUT:
 // CHECK:STDOUT:   fn[%self.param_patt: @Get.%Class (%Class.fe1)]() -> @Get.%T (%T) {
@@ -275,7 +275,7 @@ fn StaticMemberFunctionCall(T:! type) -> Class(T) {
 // CHECK:STDOUT:   %require_complete.loc7_34: <witness> = require_complete_type @GetAddr.%ptr.loc7_38.1 (%ptr.79f) [symbolic = %require_complete.loc7_34 (constants.%require_complete.6e5)]
 // CHECK:STDOUT:   %require_complete.loc7_23: <witness> = require_complete_type @GetAddr.%ptr.loc7_29.1 (%ptr.955) [symbolic = %require_complete.loc7_23 (constants.%require_complete.2ae)]
 // CHECK:STDOUT:   %require_complete.loc7_54: <witness> = require_complete_type @GetAddr.%Class (%Class.fe1) [symbolic = %require_complete.loc7_54 (constants.%require_complete.4f8)]
-// CHECK:STDOUT:   %Class.elem: type = unbound_element_type @GetAddr.%Class (%Class.fe1), @GetAddr.%T (%T) [symbolic = %Class.elem (constants.%Class.elem.e26)]
+// CHECK:STDOUT:   %Class.elem: type = unbound_element_type %Class, %T [symbolic = %Class.elem (constants.%Class.elem.e26)]
 // CHECK:STDOUT:
 // CHECK:STDOUT:   fn[addr %self.param_patt: @GetAddr.%ptr.loc7_29.1 (%ptr.955)]() -> @GetAddr.%ptr.loc7_38.1 (%ptr.79f) {
 // CHECK:STDOUT:   !entry:

toolchain/check/testdata/class/generic/member_inline.carbon

@@ -89,7 +89,7 @@ class C(T:! type) {
 // CHECK:STDOUT:   %G: @Class.%G.type (%G.type) = struct_value () [symbolic = %G (constants.%G)]
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @Class.%T.loc4_13.2 (%T) [symbolic = %require_complete (constants.%require_complete.4ae)]
 // CHECK:STDOUT:   %Class: type = class_type @Class, @Class(%T.loc4_13.2) [symbolic = %Class (constants.%Class)]
-// CHECK:STDOUT:   %Class.elem: type = unbound_element_type @Class.%Class (%Class), @Class.%T.loc4_13.2 (%T) [symbolic = %Class.elem (constants.%Class.elem)]
+// CHECK:STDOUT:   %Class.elem: type = unbound_element_type %Class, %T.loc4_13.2 [symbolic = %Class.elem (constants.%Class.elem)]
 // CHECK:STDOUT:   %struct_type.n: type = struct_type {.n: @Class.%T.loc4_13.2 (%T)} [symbolic = %struct_type.n (constants.%struct_type.n)]
 // CHECK:STDOUT:   %complete_type.loc14_1.2: <witness> = complete_type_witness @Class.%struct_type.n (%struct_type.n) [symbolic = %complete_type.loc14_1.2 (constants.%complete_type)]
 // CHECK:STDOUT:
@@ -159,7 +159,7 @@ class C(T:! type) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete.loc9: <witness> = require_complete_type @G.%Class (%Class) [symbolic = %require_complete.loc9 (constants.%require_complete.4f8)]
-// CHECK:STDOUT:   %Class.elem: type = unbound_element_type @G.%Class (%Class), @G.%T (%T) [symbolic = %Class.elem (constants.%Class.elem)]
+// CHECK:STDOUT:   %Class.elem: type = unbound_element_type %Class, %T [symbolic = %Class.elem (constants.%Class.elem)]
 // CHECK:STDOUT:   %require_complete.loc10: <witness> = require_complete_type @G.%T (%T) [symbolic = %require_complete.loc10 (constants.%require_complete.4ae)]
 // CHECK:STDOUT:
 // CHECK:STDOUT:   fn[%self.param_patt: @G.%Class (%Class)]() -> @G.%T (%T) {
@@ -245,7 +245,7 @@ class C(T:! type) {
 // CHECK:STDOUT:   %F.type: type = fn_type @F, @C(%T.loc4_9.2) [symbolic = %F.type (constants.%F.type)]
 // CHECK:STDOUT:   %F: @C.%F.type (%F.type) = struct_value () [symbolic = %F (constants.%F)]
 // CHECK:STDOUT:   %C: type = class_type @C, @C(%T.loc4_9.2) [symbolic = %C (constants.%C)]
-// CHECK:STDOUT:   %C.elem: type = unbound_element_type @C.%C (%C), %empty_struct_type [symbolic = %C.elem (constants.%C.elem)]
+// CHECK:STDOUT:   %C.elem: type = unbound_element_type %C, constants.%empty_struct_type [symbolic = %C.elem (constants.%C.elem)]
 // CHECK:STDOUT:
 // CHECK:STDOUT:   class {
 // CHECK:STDOUT:     %F.decl: @C.%F.type (%F.type) = fn_decl @F [symbolic = @C.%F (constants.%F)] {} {}
@@ -268,7 +268,7 @@ class C(T:! type) {
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %T: type = bind_symbolic_name T, 0 [symbolic = %T (constants.%T)]
 // CHECK:STDOUT:   %C: type = class_type @C, @C(%T) [symbolic = %C (constants.%C)]
-// CHECK:STDOUT:   %C.elem: type = unbound_element_type @F.%C (%C), %empty_struct_type [symbolic = %C.elem (constants.%C.elem)]
+// CHECK:STDOUT:   %C.elem: type = unbound_element_type %C, constants.%empty_struct_type [symbolic = %C.elem (constants.%C.elem)]
 // CHECK:STDOUT:
 // CHECK:STDOUT:   fn() {
 // CHECK:STDOUT:   !entry:

toolchain/check/testdata/class/generic/member_lookup.carbon

@@ -206,7 +206,7 @@ fn AccessMissingConcrete(x: Derived(i32)) -> i32 {
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @Base.%T.loc4_17.2 (%T) [symbolic = %require_complete (constants.%require_complete.4ae)]
 // CHECK:STDOUT:   %Base: type = class_type @Base, @Base(%T.loc4_17.2) [symbolic = %Base (constants.%Base.370)]
-// CHECK:STDOUT:   %Base.elem: type = unbound_element_type @Base.%Base (%Base.370), @Base.%T.loc4_17.2 (%T) [symbolic = %Base.elem (constants.%Base.elem.9af)]
+// CHECK:STDOUT:   %Base.elem: type = unbound_element_type %Base, %T.loc4_17.2 [symbolic = %Base.elem (constants.%Base.elem.9af)]
 // CHECK:STDOUT:   %struct_type.b: type = struct_type {.b: @Base.%T.loc4_17.2 (%T)} [symbolic = %struct_type.b (constants.%struct_type.b.f69)]
 // CHECK:STDOUT:   %complete_type.loc6_1.2: <witness> = complete_type_witness @Base.%struct_type.b (%struct_type.b.f69) [symbolic = %complete_type.loc6_1.2 (constants.%complete_type.eaf)]
 // CHECK:STDOUT:
@@ -234,9 +234,9 @@ fn AccessMissingConcrete(x: Derived(i32)) -> i32 {
 // CHECK:STDOUT:   %Base.loc9_22.2: type = class_type @Base, @Base(%T.loc8_15.2) [symbolic = %Base.loc9_22.2 (constants.%Base.370)]
 // CHECK:STDOUT:   %require_complete.loc9: <witness> = require_complete_type @Derived.%Base.loc9_22.2 (%Base.370) [symbolic = %require_complete.loc9 (constants.%require_complete.97d)]
 // CHECK:STDOUT:   %Derived: type = class_type @Derived, @Derived(%T.loc8_15.2) [symbolic = %Derived (constants.%Derived.85c)]
-// CHECK:STDOUT:   %Derived.elem.loc9: type = unbound_element_type @Derived.%Derived (%Derived.85c), @Derived.%Base.loc9_22.2 (%Base.370) [symbolic = %Derived.elem.loc9 (constants.%Derived.elem.8b3)]
+// CHECK:STDOUT:   %Derived.elem.loc9: type = unbound_element_type %Derived, %Base.loc9_22.2 [symbolic = %Derived.elem.loc9 (constants.%Derived.elem.8b3)]
 // CHECK:STDOUT:   %require_complete.loc10: <witness> = require_complete_type @Derived.%T.loc8_15.2 (%T) [symbolic = %require_complete.loc10 (constants.%require_complete.4ae)]
-// CHECK:STDOUT:   %Derived.elem.loc10: type = unbound_element_type @Derived.%Derived (%Derived.85c), @Derived.%T.loc8_15.2 (%T) [symbolic = %Derived.elem.loc10 (constants.%Derived.elem.6d2)]
+// CHECK:STDOUT:   %Derived.elem.loc10: type = unbound_element_type %Derived, %T.loc8_15.2 [symbolic = %Derived.elem.loc10 (constants.%Derived.elem.6d2)]
 // CHECK:STDOUT:   %struct_type.base.d: type = struct_type {.base: @Derived.%Base.loc9_22.2 (%Base.370), .d: @Derived.%T.loc8_15.2 (%T)} [symbolic = %struct_type.base.d (constants.%struct_type.base.d.37c)]
 // CHECK:STDOUT:   %complete_type.loc11_1.2: <witness> = complete_type_witness @Derived.%struct_type.base.d (%struct_type.base.d.37c) [symbolic = %complete_type.loc11_1.2 (constants.%complete_type.8ad)]
 // CHECK:STDOUT:
@@ -271,7 +271,7 @@ fn AccessMissingConcrete(x: Derived(i32)) -> i32 {
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete.loc13: <witness> = require_complete_type @AccessDerived.%Derived.loc13_40.2 (%Derived.85c) [symbolic = %require_complete.loc13 (constants.%require_complete.5f4)]
-// CHECK:STDOUT:   %Derived.elem: type = unbound_element_type @AccessDerived.%Derived.loc13_40.2 (%Derived.85c), @AccessDerived.%T.loc13_18.2 (%T) [symbolic = %Derived.elem (constants.%Derived.elem.6d2)]
+// CHECK:STDOUT:   %Derived.elem: type = unbound_element_type %Derived.loc13_40.2, %T.loc13_18.2 [symbolic = %Derived.elem (constants.%Derived.elem.6d2)]
 // CHECK:STDOUT:   %require_complete.loc14: <witness> = require_complete_type @AccessDerived.%T.loc13_18.2 (%T) [symbolic = %require_complete.loc14 (constants.%require_complete.4ae)]
 // CHECK:STDOUT:
 // CHECK:STDOUT:   fn[%T.patt.loc13_18.1: type](%x.param_patt: @AccessDerived.%Derived.loc13_40.2 (%Derived.85c)) -> @AccessDerived.%T.loc13_18.2 (%T) {
@@ -293,7 +293,7 @@ fn AccessMissingConcrete(x: Derived(i32)) -> i32 {
 // CHECK:STDOUT:   %require_complete.loc17: <witness> = require_complete_type @AccessBase.%Derived.loc17_37.2 (%Derived.85c) [symbolic = %require_complete.loc17 (constants.%require_complete.5f4)]
 // CHECK:STDOUT:   %Base: type = class_type @Base, @Base(%T.loc17_15.2) [symbolic = %Base (constants.%Base.370)]
 // CHECK:STDOUT:   %require_complete.loc18_11: <witness> = require_complete_type @AccessBase.%Base (%Base.370) [symbolic = %require_complete.loc18_11 (constants.%require_complete.97d)]
-// CHECK:STDOUT:   %Base.elem: type = unbound_element_type @AccessBase.%Base (%Base.370), @AccessBase.%T.loc17_15.2 (%T) [symbolic = %Base.elem (constants.%Base.elem.9af)]
+// CHECK:STDOUT:   %Base.elem: type = unbound_element_type %Base, %T.loc17_15.2 [symbolic = %Base.elem (constants.%Base.elem.9af)]
 // CHECK:STDOUT:   %require_complete.loc18_13: <witness> = require_complete_type @AccessBase.%T.loc17_15.2 (%T) [symbolic = %require_complete.loc18_13 (constants.%require_complete.4ae)]
 // CHECK:STDOUT:
 // CHECK:STDOUT:   fn[%T.patt.loc17_15.1: type](%x.param_patt: @AccessBase.%Derived.loc17_37.2 (%Derived.85c)) -> @AccessBase.%T.loc17_15.2 (%T) {
@@ -533,7 +533,7 @@ fn AccessMissingConcrete(x: Derived(i32)) -> i32 {
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @Base.%T.loc4_17.2 (%T) [symbolic = %require_complete (constants.%require_complete.4ae)]
 // CHECK:STDOUT:   %Base: type = class_type @Base, @Base(%T.loc4_17.2) [symbolic = %Base (constants.%Base.370)]
-// CHECK:STDOUT:   %Base.elem: type = unbound_element_type @Base.%Base (%Base.370), @Base.%T.loc4_17.2 (%T) [symbolic = %Base.elem (constants.%Base.elem.9af)]
+// CHECK:STDOUT:   %Base.elem: type = unbound_element_type %Base, %T.loc4_17.2 [symbolic = %Base.elem (constants.%Base.elem.9af)]
 // CHECK:STDOUT:   %struct_type.b: type = struct_type {.b: @Base.%T.loc4_17.2 (%T)} [symbolic = %struct_type.b (constants.%struct_type.b.f69)]
 // CHECK:STDOUT:   %complete_type.loc6_1.2: <witness> = complete_type_witness @Base.%struct_type.b (%struct_type.b.f69) [symbolic = %complete_type.loc6_1.2 (constants.%complete_type.eaf)]
 // CHECK:STDOUT:
@@ -562,9 +562,9 @@ fn AccessMissingConcrete(x: Derived(i32)) -> i32 {
 // CHECK:STDOUT:   %Base.loc9_22.2: type = class_type @Base, @Base(%T.loc8_15.2) [symbolic = %Base.loc9_22.2 (constants.%Base.370)]
 // CHECK:STDOUT:   %require_complete.loc9: <witness> = require_complete_type @Derived.%Base.loc9_22.2 (%Base.370) [symbolic = %require_complete.loc9 (constants.%require_complete.97d)]
 // CHECK:STDOUT:   %Derived: type = class_type @Derived, @Derived(%T.loc8_15.2) [symbolic = %Derived (constants.%Derived.85c)]
-// CHECK:STDOUT:   %Derived.elem.loc9: type = unbound_element_type @Derived.%Derived (%Derived.85c), @Derived.%Base.loc9_22.2 (%Base.370) [symbolic = %Derived.elem.loc9 (constants.%Derived.elem.8b3)]
+// CHECK:STDOUT:   %Derived.elem.loc9: type = unbound_element_type %Derived, %Base.loc9_22.2 [symbolic = %Derived.elem.loc9 (constants.%Derived.elem.8b3)]
 // CHECK:STDOUT:   %require_complete.loc10: <witness> = require_complete_type @Derived.%T.loc8_15.2 (%T) [symbolic = %require_complete.loc10 (constants.%require_complete.4ae)]
-// CHECK:STDOUT:   %Derived.elem.loc10: type = unbound_element_type @Derived.%Derived (%Derived.85c), @Derived.%T.loc8_15.2 (%T) [symbolic = %Derived.elem.loc10 (constants.%Derived.elem.6d2)]
+// CHECK:STDOUT:   %Derived.elem.loc10: type = unbound_element_type %Derived, %T.loc8_15.2 [symbolic = %Derived.elem.loc10 (constants.%Derived.elem.6d2)]
 // CHECK:STDOUT:   %struct_type.base.d: type = struct_type {.base: @Derived.%Base.loc9_22.2 (%Base.370), .d: @Derived.%T.loc8_15.2 (%T)} [symbolic = %struct_type.base.d (constants.%struct_type.base.d.37c)]
 // CHECK:STDOUT:   %complete_type.loc11_1.2: <witness> = complete_type_witness @Derived.%struct_type.base.d (%struct_type.base.d.37c) [symbolic = %complete_type.loc11_1.2 (constants.%complete_type.8ad)]
 // CHECK:STDOUT:

toolchain/check/testdata/class/generic/member_out_of_line.carbon

@@ -187,7 +187,7 @@ fn Generic(T:! ()).WrongType() {}
 // CHECK:STDOUT:   %G: @Class.%G.type (%G.type) = struct_value () [symbolic = %G (constants.%G)]
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @Class.%T.loc4_13.2 (%T) [symbolic = %require_complete (constants.%require_complete.4ae)]
 // CHECK:STDOUT:   %Class: type = class_type @Class, @Class(%T.loc4_13.2) [symbolic = %Class (constants.%Class)]
-// CHECK:STDOUT:   %Class.elem: type = unbound_element_type @Class.%Class (%Class), @Class.%T.loc4_13.2 (%T) [symbolic = %Class.elem (constants.%Class.elem)]
+// CHECK:STDOUT:   %Class.elem: type = unbound_element_type %Class, %T.loc4_13.2 [symbolic = %Class.elem (constants.%Class.elem)]
 // CHECK:STDOUT:   %struct_type.n: type = struct_type {.n: @Class.%T.loc4_13.2 (%T)} [symbolic = %struct_type.n (constants.%struct_type.n)]
 // CHECK:STDOUT:   %complete_type.loc8_1.2: <witness> = complete_type_witness @Class.%struct_type.n (%struct_type.n) [symbolic = %complete_type.loc8_1.2 (constants.%complete_type)]
 // CHECK:STDOUT:
@@ -257,7 +257,7 @@ fn Generic(T:! ()).WrongType() {}
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete.loc14: <witness> = require_complete_type @G.%Class (%Class) [symbolic = %require_complete.loc14 (constants.%require_complete.4f8)]
-// CHECK:STDOUT:   %Class.elem: type = unbound_element_type @G.%Class (%Class), @G.%T.loc6 (%T) [symbolic = %Class.elem (constants.%Class.elem)]
+// CHECK:STDOUT:   %Class.elem: type = unbound_element_type %Class, %T.loc6 [symbolic = %Class.elem (constants.%Class.elem)]
 // CHECK:STDOUT:   %require_complete.loc15: <witness> = require_complete_type @G.%T.loc6 (%T) [symbolic = %require_complete.loc15 (constants.%require_complete.4ae)]
 // CHECK:STDOUT:
 // CHECK:STDOUT:   fn[%self.param_patt: @G.%Class (%Class)]() -> @G.%T.loc6 (%T) {

toolchain/check/testdata/class/generic_method.carbon

@@ -76,7 +76,7 @@ fn Class(T:! type).F[self: Self](n: T) {}
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @Class.%T.loc11_13.2 (%T) [symbolic = %require_complete (constants.%require_complete.4ae)]
 // CHECK:STDOUT:   %Class: type = class_type @Class, @Class(%T.loc11_13.2) [symbolic = %Class (constants.%Class)]
-// CHECK:STDOUT:   %Class.elem: type = unbound_element_type @Class.%Class (%Class), @Class.%T.loc11_13.2 (%T) [symbolic = %Class.elem (constants.%Class.elem)]
+// CHECK:STDOUT:   %Class.elem: type = unbound_element_type %Class, %T.loc11_13.2 [symbolic = %Class.elem (constants.%Class.elem)]
 // CHECK:STDOUT:   %F.type: type = fn_type @F, @Class(%T.loc11_13.2) [symbolic = %F.type (constants.%F.type)]
 // CHECK:STDOUT:   %F: @Class.%F.type (%F.type) = struct_value () [symbolic = %F (constants.%F)]
 // CHECK:STDOUT:   %struct_type.a: type = struct_type {.a: @Class.%T.loc11_13.2 (%T)} [symbolic = %struct_type.a (constants.%struct_type.a)]

toolchain/check/testdata/generic/complete_type.carbon

@@ -150,7 +150,7 @@ fn G() { F(B); }
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @A.%T.loc6_9.2 (%T) [symbolic = %require_complete (constants.%require_complete)]
 // CHECK:STDOUT:   %A: type = class_type @A, @A(%T.loc6_9.2) [symbolic = %A (constants.%A.130)]
-// CHECK:STDOUT:   %A.elem: type = unbound_element_type @A.%A (%A.130), @A.%T.loc6_9.2 (%T) [symbolic = %A.elem (constants.%A.elem.1ce)]
+// CHECK:STDOUT:   %A.elem: type = unbound_element_type %A, %T.loc6_9.2 [symbolic = %A.elem (constants.%A.elem.1ce)]
 // CHECK:STDOUT:   %struct_type.v: type = struct_type {.v: @A.%T.loc6_9.2 (%T)} [symbolic = %struct_type.v (constants.%struct_type.v.ff1)]
 // CHECK:STDOUT:   %complete_type.loc14_1.2: <witness> = complete_type_witness @A.%struct_type.v (%struct_type.v.ff1) [symbolic = %complete_type.loc14_1.2 (constants.%complete_type.460)]
 // CHECK:STDOUT:

toolchain/check/testdata/generic/local.carbon

@@ -106,7 +106,7 @@ class C(C:! type) {
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @C.%T.loc5_11.2 (%T) [symbolic = %require_complete (constants.%require_complete.4ae)]
 // CHECK:STDOUT:   %C: type = class_type @C, @C(%T.loc5_11.2) [symbolic = %C (constants.%C.f06)]
-// CHECK:STDOUT:   %C.elem: type = unbound_element_type @C.%C (%C.f06), @C.%T.loc5_11.2 (%T) [symbolic = %C.elem (constants.%C.elem.cca)]
+// CHECK:STDOUT:   %C.elem: type = unbound_element_type %C, %T.loc5_11.2 [symbolic = %C.elem (constants.%C.elem.cca)]
 // CHECK:STDOUT:   %struct_type.x: type = struct_type {.x: @C.%T.loc5_11.2 (%T)} [symbolic = %struct_type.x (constants.%struct_type.x.2ac)]
 // CHECK:STDOUT:   %complete_type.loc7_3.2: <witness> = complete_type_witness @C.%struct_type.x (%struct_type.x.2ac) [symbolic = %complete_type.loc7_3.2 (constants.%complete_type.4339)]
 // CHECK:STDOUT:

toolchain/check/testdata/impl/lookup/no_prelude/impl_forall.carbon

@@ -276,7 +276,7 @@ fn TestSpecific(a: A({})) -> {} {
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete: <witness> = require_complete_type @A.%T.loc3_9.2 (%T) [symbolic = %require_complete (constants.%require_complete.4aeca8.1)]
 // CHECK:STDOUT:   %A: type = class_type @A, @A(%T.loc3_9.2) [symbolic = %A (constants.%A.13025a.1)]
-// CHECK:STDOUT:   %A.elem: type = unbound_element_type @A.%A (%A.13025a.1), @A.%T.loc3_9.2 (%T) [symbolic = %A.elem (constants.%A.elem.1ceb36.1)]
+// CHECK:STDOUT:   %A.elem: type = unbound_element_type %A, %T.loc3_9.2 [symbolic = %A.elem (constants.%A.elem.1ceb36.1)]
 // CHECK:STDOUT:   %struct_type.n: type = struct_type {.n: @A.%T.loc3_9.2 (%T)} [symbolic = %struct_type.n (constants.%struct_type.n.848971.1)]
 // CHECK:STDOUT:   %complete_type.loc5_1.2: <witness> = complete_type_witness @A.%struct_type.n (%struct_type.n.848971.1) [symbolic = %complete_type.loc5_1.2 (constants.%complete_type.84bb3d.1)]
 // CHECK:STDOUT:
@@ -312,7 +312,7 @@ fn TestSpecific(a: A({})) -> {} {
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete.loc12_22: <witness> = require_complete_type @F.2.%V (%V) [symbolic = %require_complete.loc12_22 (constants.%require_complete.4aeca8.2)]
 // CHECK:STDOUT:   %require_complete.loc12_12: <witness> = require_complete_type @F.2.%A (%A.13025a.2) [symbolic = %require_complete.loc12_12 (constants.%require_complete.5b8aee.1)]
-// CHECK:STDOUT:   %A.elem: type = unbound_element_type @F.2.%A (%A.13025a.2), @F.2.%V (%V) [symbolic = %A.elem (constants.%A.elem.1ceb36.2)]
+// CHECK:STDOUT:   %A.elem: type = unbound_element_type %A, %V [symbolic = %A.elem (constants.%A.elem.1ceb36.2)]
 // CHECK:STDOUT:
 // CHECK:STDOUT:   fn[%self.param_patt: @F.2.%A (%A.13025a.2)]() -> @F.2.%V (%V) {
 // CHECK:STDOUT:   !entry:

toolchain/check/type.cpp

@@ -157,8 +157,8 @@ auto GetPointerType(Context& context, SemIR::InstId pointee_type_id)
   return GetTypeImpl<SemIR::PointerType>(context, pointee_type_id);
 }
 
-auto GetUnboundElementType(Context& context, SemIR::TypeId class_type_id,
-                           SemIR::TypeId element_type_id) -> SemIR::TypeId {
+auto GetUnboundElementType(Context& context, SemIR::InstId class_type_id,
+                           SemIR::InstId element_type_id) -> SemIR::TypeId {
   return GetTypeImpl<SemIR::UnboundElementType>(context, class_type_id,
                                                 element_type_id);
 }

toolchain/check/type.h

@@ -83,8 +83,8 @@ auto GetTupleType(Context& context, llvm::ArrayRef<SemIR::TypeId> type_ids)
     -> SemIR::TypeId;
 
 // Returns an unbound element type.
-auto GetUnboundElementType(Context& context, SemIR::TypeId class_type_id,
-                           SemIR::TypeId element_type_id) -> SemIR::TypeId;
+auto GetUnboundElementType(Context& context, SemIR::InstId class_type_id,
+                           SemIR::InstId element_type_id) -> SemIR::TypeId;
 
 }  // namespace Carbon::Check
 

toolchain/sem_ir/inst_namer.cpp

@@ -928,7 +928,7 @@ auto InstNamer::CollectNamesInBlock(ScopeId top_scope_id,
       }
       case CARBON_KIND(UnboundElementType inst): {
         if (auto class_ty =
-                sem_ir_->types().TryGetAs<ClassType>(inst.class_type_id)) {
+                sem_ir_->insts().TryGetAs<ClassType>(inst.class_type_inst_id)) {
           add_inst_name_id(sem_ir_->classes().Get(class_ty->class_id).name_id,
                            ".elem");
         } else {

toolchain/sem_ir/stringify_type.cpp

@@ -638,7 +638,7 @@ class Stringifier {
   auto StringifyTypeInst(SemIR::InstId /*inst_id*/, UnboundElementType inst)
       -> void {
     *out_ << "<unbound element of class ";
-    step_stack_->Push(inst.class_type_id, ">");
+    step_stack_->Push(inst.class_type_inst_id, ">");
   }
 
   auto StringifyTypeInst(SemIR::InstId /*inst_id*/, VtablePtr /*inst*/)

toolchain/sem_ir/typed_insts.h

@@ -1781,10 +1781,10 @@ struct UnboundElementType {
        .constant_kind = InstConstantKind::WheneverPossible});
 
   TypeId type_id;
-  // The class that a value of this type is an element of.
-  TypeId class_type_id;
+  // The `ClassType` that a value of this type is an element of.
+  InstId class_type_inst_id;
   // The type of the element.
-  TypeId element_type_id;
+  InstId element_type_inst_id;
 };
 
 // Converts from a value expression to an ephemeral reference expression, in