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Drop Singleton from ErrorInst::SingletonInstId and similar (#5304)

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We frequently want to operate on singletons. Per discussion, drop
`Singleton` to make the code shorter.

This started off as wanting to write `inst_id.is_error()`, but the
dependency relationship between ids.h and singleton_insts.h would
require some kind of delayed evaluation to allow the implementation to
remain in headers (which I suspect is helpful to have for inlining). I
could have added something like `IsErrorInst`, forward declared in ids.h
and defined in singleton_insts.h (which would always be included by
typed_insts.h), but the template approach felt like a decent balance
between (a) removing the boilerplate `::SingletonInstId`, (b)
understandability, (c) still visually mirroring if we immediately return
a singleton, and (d) flexibility for more than just `ErrorInst`. But TBH
I'd probably still have written `is_error()` if it didn't require
addressing the cross-header cycle.

Then I tried `SemIR::InstId::Is<SemIR::ErrorInst>`, which generally
worked with types but generated the complaint that it didn't shorten
*all* singleton uses. So pulling back on `::Is`, and instead just
dropping `Singleton`.
This commit is contained in:
Jon Ross-Perkins
2025-04-15 22:40:29 +00:00
committed by GitHub
parent 838417e358
commit 4923445e3a
64 changed files with 489 additions and 539 deletions
Download Patch File Download Diff File Expand all files Collapse all files
toolchain/check/impl.cpp
+17 -18
View File
@@ -56,7 +56,7 @@ static auto CheckAssociatedFunctionImplementation(
interface_function_type.function_id);
builder.Emit();
return SemIR::ErrorInst::SingletonInstId;
return SemIR::ErrorInst::InstId;
}
auto impl_enclosing_specific_id =
@@ -80,7 +80,7 @@ static auto CheckAssociatedFunctionImplementation(
context.functions().Get(interface_function_type.function_id),
interface_function_specific_id, /*check_syntax=*/false,
/*check_self=*/true)) {
return SemIR::ErrorInst::SingletonInstId;
return SemIR::ErrorInst::InstId;
}
return impl_decl_id;
}
@@ -91,9 +91,9 @@ auto ImplWitnessForDeclaration(Context& context, const SemIR::Impl& impl,
CARBON_CHECK(!impl.has_definition_started());
auto self_type_id = context.types().GetTypeIdForTypeInstId(impl.self_id);
if (self_type_id == SemIR::ErrorInst::SingletonTypeId) {
if (self_type_id == SemIR::ErrorInst::TypeId) {
// When 'impl as' is invalid, the self type is an error.
return SemIR::ErrorInst::SingletonInstId;
return SemIR::ErrorInst::InstId;
}
return InitialFacetTypeImplWitness(
@@ -105,7 +105,7 @@ auto ImplWitnessForDeclaration(Context& context, const SemIR::Impl& impl,
auto ImplWitnessStartDefinition(Context& context, SemIR::Impl& impl) -> void {
CARBON_CHECK(impl.is_being_defined());
CARBON_CHECK(impl.witness_id.has_value());
if (impl.witness_id == SemIR::ErrorInst::SingletonInstId) {
if (impl.witness_id == SemIR::ErrorInst::InstId) {
return;
}
auto witness = context.insts().GetAs<SemIR::ImplWitness>(impl.witness_id);
@@ -143,8 +143,7 @@ auto ImplWitnessStartDefinition(Context& context, SemIR::Impl& impl) -> void {
CARBON_CHECK(decl_id.has_value(), "Non-constant associated entity");
if (auto decl =
context.insts().TryGetAs<SemIR::AssociatedConstantDecl>(decl_id)) {
if (witness_value ==
SemIR::ImplWitnessTablePlaceholder::SingletonInstId) {
if (witness_value == SemIR::ImplWitnessTablePlaceholder::InstId) {
CARBON_DIAGNOSTIC(ImplAssociatedConstantNeedsValue, Error,
"associated constant {0} not given a value in impl "
"of interface {1}",
@@ -160,7 +159,7 @@ auto ImplWitnessStartDefinition(Context& context, SemIR::Impl& impl) -> void {
.Note(assoc_entity, AssociatedConstantHere)
.Emit();
witness_value = SemIR::ErrorInst::SingletonInstId;
witness_value = SemIR::ErrorInst::InstId;
}
}
}
@@ -171,7 +170,7 @@ auto ImplWitnessStartDefinition(Context& context, SemIR::Impl& impl) -> void {
auto FinishImplWitness(Context& context, SemIR::Impl& impl) -> void {
CARBON_CHECK(impl.is_being_defined());
CARBON_CHECK(impl.witness_id.has_value());
if (impl.witness_id == SemIR::ErrorInst::SingletonInstId) {
if (impl.witness_id == SemIR::ErrorInst::InstId) {
return;
}
auto witness = context.insts().GetAs<SemIR::ImplWitness>(impl.witness_id);
@@ -195,8 +194,8 @@ auto FinishImplWitness(Context& context, SemIR::Impl& impl) -> void {
auto decl = context.insts().Get(decl_id);
CARBON_KIND_SWITCH(decl) {
case CARBON_KIND(SemIR::StructValue struct_value): {
if (struct_value.type_id == SemIR::ErrorInst::SingletonTypeId) {
witness_value = SemIR::ErrorInst::SingletonInstId;
if (struct_value.type_id == SemIR::ErrorInst::TypeId) {
witness_value = SemIR::ErrorInst::InstId;
break;
}
auto type_inst = context.types().GetAsInst(struct_value.type_id);
@@ -224,7 +223,7 @@ auto FinishImplWitness(Context& context, SemIR::Impl& impl) -> void {
NoteAssociatedFunction(context, builder, fn_type->function_id);
builder.Emit();
witness_value = SemIR::ErrorInst::SingletonInstId;
witness_value = SemIR::ErrorInst::InstId;
}
break;
}
@@ -233,9 +232,9 @@ auto FinishImplWitness(Context& context, SemIR::Impl& impl) -> void {
break;
}
default:
CARBON_CHECK(decl_id == SemIR::ErrorInst::SingletonInstId,
CARBON_CHECK(decl_id == SemIR::ErrorInst::InstId,
"Unexpected kind of associated entity {0}", decl);
witness_value = SemIR::ErrorInst::SingletonInstId;
witness_value = SemIR::ErrorInst::InstId;
break;
}
}
@@ -245,15 +244,15 @@ auto FinishImplWitness(Context& context, SemIR::Impl& impl) -> void {
auto FillImplWitnessWithErrors(Context& context, SemIR::Impl& impl) -> void {
if (impl.witness_id.has_value() &&
impl.witness_id != SemIR::ErrorInst::SingletonInstId) {
impl.witness_id != SemIR::ErrorInst::InstId) {
auto witness = context.insts().GetAs<SemIR::ImplWitness>(impl.witness_id);
auto witness_table = context.insts().GetAs<SemIR::ImplWitnessTable>(
witness.witness_table_id);
auto witness_block =
context.inst_blocks().GetMutable(witness_table.elements_id);
for (auto& elem : witness_block) {
if (elem == SemIR::ImplWitnessTablePlaceholder::SingletonInstId) {
elem = SemIR::ErrorInst::SingletonInstId;
if (elem == SemIR::ImplWitnessTablePlaceholder::InstId) {
elem = SemIR::ErrorInst::InstId;
}
}
}
@@ -261,7 +260,7 @@ auto FillImplWitnessWithErrors(Context& context, SemIR::Impl& impl) -> void {
auto AssignImplIdInWitness(Context& context, SemIR::ImplId impl_id,
SemIR::InstId witness_id) -> void {
if (witness_id == SemIR::ErrorInst::SingletonInstId) {
if (witness_id == SemIR::ErrorInst::InstId) {
return;
}
auto witness = context.insts().GetAs<SemIR::ImplWitness>(witness_id);