Respond to reviewer comments

toolchain/check/call.cpp

@@ -175,7 +175,7 @@ auto PerformCall(Context& context, SemIR::LocId loc_id, SemIR::InstId callee_id,
   }
 
   // If there is a return slot, build storage for the result.
-  SemIR::InstId return_slot_id = SemIR::InstId::Invalid;
+  SemIR::InstId return_slot_arg_id = SemIR::InstId::Invalid;
   SemIR::ReturnTypeInfo return_info = [&] {
     DiagnosticAnnotationScope annotate_diagnostics(
         &context.emitter(), [&](auto& builder) {
@@ -190,7 +190,7 @@ auto PerformCall(Context& context, SemIR::LocId loc_id, SemIR::InstId callee_id,
     case SemIR::InitRepr::InPlace:
       // Tentatively put storage for a temporary in the function's return slot.
       // This will be replaced if necessary when we perform initialization.
-      return_slot_id = context.AddInst<SemIR::TemporaryStorage>(
+      return_slot_arg_id = context.AddInst<SemIR::TemporaryStorage>(
           loc_id, {.type_id = return_info.type_id});
       break;
     case SemIR::InitRepr::None:
@@ -211,7 +211,7 @@ auto PerformCall(Context& context, SemIR::LocId loc_id, SemIR::InstId callee_id,
 
   // Convert the arguments to match the parameters.
   auto converted_args_id = ConvertCallArgs(
-      context, loc_id, callee_function.self_id, arg_ids, return_slot_id,
+      context, loc_id, callee_function.self_id, arg_ids, return_slot_arg_id,
       CalleeParamsInfo(callable), *callee_specific_id);
   auto call_inst_id =
       context.AddInst<SemIR::Call>(loc_id, {.type_id = return_info.type_id,

toolchain/check/convert.cpp

@@ -1172,7 +1172,7 @@ static auto ConvertSelf(Context& context, SemIR::LocId call_loc_id,
 auto ConvertCallArgs(Context& context, SemIR::LocId call_loc_id,
                      SemIR::InstId self_id,
                      llvm::ArrayRef<SemIR::InstId> arg_refs,
-                     SemIR::InstId return_slot_id,
+                     SemIR::InstId return_slot_arg_id,
                      const CalleeParamsInfo& callee,
                      SemIR::SpecificId callee_specific_id)
     -> SemIR::InstBlockId {
@@ -1187,7 +1187,7 @@ auto ConvertCallArgs(Context& context, SemIR::LocId call_loc_id,
   // Start building a block to hold the converted arguments.
   llvm::SmallVector<SemIR::InstId> args;
   args.reserve(implicit_param_patterns.size() + param_patterns.size() +
-               return_slot_id.is_valid());
+               return_slot_arg_id.is_valid());
 
   // Check implicit parameters.
   for (auto implicit_param_id : implicit_param_patterns) {
@@ -1241,8 +1241,8 @@ auto ConvertCallArgs(Context& context, SemIR::LocId call_loc_id,
   }
 
   // Track the return storage, if present.
-  if (return_slot_id.is_valid()) {
-    args.push_back(return_slot_id);
+  if (return_slot_arg_id.is_valid()) {
+    args.push_back(return_slot_arg_id);
   }
 
   return context.inst_blocks().AddOrEmpty(args);

toolchain/check/convert.h

@@ -117,7 +117,7 @@ struct CalleeParamsInfo {
 auto ConvertCallArgs(Context& context, SemIR::LocId call_loc_id,
                      SemIR::InstId self_id,
                      llvm::ArrayRef<SemIR::InstId> arg_refs,
-                     SemIR::InstId return_slot_id,
+                     SemIR::InstId return_slot_arg_id,
                      const CalleeParamsInfo& callee,
                      SemIR::SpecificId callee_specific_id)
     -> SemIR::InstBlockId;

toolchain/check/import_ref.cpp

@@ -764,7 +764,7 @@ class ImportRefResolver {
           AddImportIRInst(param_id),
           {.type_id = type_id,
            .runtime_index = param_inst.runtime_index,
-           .pretty_name = GetLocalNameId(param_inst.pretty_name)});
+           .pretty_name_id = GetLocalNameId(param_inst.pretty_name_id)});
       switch (bind_inst.kind) {
         case SemIR::BindName::Kind: {
           auto entity_name_id = context_.entity_names().Add(

toolchain/check/pattern_match.cpp

@@ -247,7 +247,7 @@ auto EmitPatternMatch(Context& context, MatchContext& match,
                    pattern.loc_id,
                    {.type_id = param_pattern.type_id,
                     .runtime_index = param_pattern.runtime_index,
-                    .pretty_name = GetPrettyName(context, param_pattern)})});
+                    .pretty_name_id = GetPrettyName(context, param_pattern)})});
         } break;
       }
       break;
@@ -256,7 +256,7 @@ auto EmitPatternMatch(Context& context, MatchContext& match,
       CARBON_CHECK(match.kind() == MatchKind::Callee);
       match.set_return_slot_id(context.AddInst<SemIR::ReturnSlot>(
           pattern.loc_id, {.type_id = return_slot_pattern.type_id,
-                           .value_id = entry.scrutinee_id}));
+                           .storage_id = entry.scrutinee_id}));
       break;
     }
     default: {

toolchain/sem_ir/inst_namer.cpp

@@ -531,8 +531,7 @@ auto InstNamer::CollectNamesInBlock(ScopeId scope_id,
         continue;
       }
       case CARBON_KIND(Param inst): {
-        // TODO: Find a way to use the name of the enclosing bind inst here.
-        add_inst_name_id(inst.pretty_name, ".param");
+        add_inst_name_id(inst.pretty_name_id, ".param");
         continue;
       }
       case InstKind::ParamPattern: {

toolchain/sem_ir/typed_insts.h

@@ -836,7 +836,7 @@ struct Param {
 
   // A name to associate with this Param in pretty-printed IR. This is not
   // necessarily unique, or even valid, and has no semantic significance.
-  NameId pretty_name;
+  NameId pretty_name_id;
 };
 
 // A pattern that represents a parameter. It matches the same values as
@@ -892,8 +892,12 @@ struct ReturnSlot {
   static constexpr auto Kind =
       InstKind::ReturnSlot.Define<Parse::NodeId>({.ir_name = "return_slot"});
 
+  // The type of the value that will be stored in this slot (i.e. the return
+  // type of the function).
   TypeId type_id;
-  InstId value_id;
+
+  // The storage that will be initialized by the function.
+  InstId storage_id;
 };
 
 // The return slot of a function declaration, as exposed to the function's