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Add an interface-with-self generic to each interface and same for constraints (#6667)

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Currently each interface has a `Self` facet internally that becomes a
binding to every entity inside the interface: associated constants,
functions, and require decls. Each of these has to be independently
generic as a result. This makes is challenging in extended name lookup
to move into an extended scope of an interface, as we have a specific
for the interface, but the names within require a different specific
that includes a `Self` facet value.

We generalize this relationship by adding a second generic to Interface,
called `generic_with_self`. When we want to work with entities inside
the interface, we move from the interface-without-specific to the
interface-with-self specific by adding a Self to the specific. This is
done independently of any particular entity inside the Interface, as
those entities are now all members of the interface-with-self generic.

Associated constants no longer need a generic of their own, as they do
not have separate generic bindings. Functions retain a generic, but if
the function has no generic arguments, it will have no bindings of its
own now.

Require decls retain a generic so that their specific can be
instantiated separately from the interface. Requiring the interface to
be complete does not require the types in a require decl to be complete
unless it is modified by `extend`. So we allow them to be completed
later by keeping them in a separate generic.

Named constraints look like interfaces and gain the additional inner
generic-with-self, with the same relationship to require decls.

This removes the need for name lookup to perform Substitution of a Self
facet into the extended scope instruction. Instead, the
`SpecificConstant` instruction inserted by a `require` decl is part of
the interface-with-self generic. When looking through a FacetType for
extended scopes, for each interface, we push the scope with the specific
for the interface-with-self. Then the constant value of the
`SpecificConstant` is correctly modified by the provided self
automatically through applying that specific.
This commit is contained in:
Dana Jansens
2026-02-19 16:24:07 +00:00
committed by GitHub
parent e5b094fdad
commit 917a6ea971
419 changed files with 18175 additions and 11940 deletions
Download Patch File Download Diff File Expand all files Collapse all files
toolchain/check/interface.cpp
+26 -126
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@@ -33,9 +33,10 @@ auto BuildAssociatedEntity(Context& context, SemIR::InterfaceId interface_id,
return SemIR::ErrorInst::InstId;
}
// This associated entity is being declared as a member of the self specific
// of the interface.
auto interface_specific_id =
// This associated entity is being declared as a member of an interface. We
// use the self-specific of the interface-without-self as the AssociatedEntity
// names the externally facing SpecificInterface (without self).
auto interface_without_self_specific_id =
context.generics().GetSelfSpecific(interface_info.generic_id);
// Register this declaration as declaring an associated entity.
@@ -45,114 +46,24 @@ auto BuildAssociatedEntity(Context& context, SemIR::InterfaceId interface_id,
// Name lookup for the declaration's name should name the associated entity,
// not the declaration itself.
auto type_id =
GetAssociatedEntityType(context, interface_id, interface_specific_id);
auto type_id = GetAssociatedEntityType(context, interface_id,
interface_without_self_specific_id);
return AddInst<SemIR::AssociatedEntity>(
context, SemIR::LocId(decl_id),
{.type_id = type_id, .index = index, .decl_id = decl_id});
}
// Returns the `Self` binding for an interface, given a specific for the
// interface and a generic for an associated entity within it.
static auto GetSelfBinding(Context& context,
SemIR::SpecificId interface_specific_id,
SemIR::GenericId assoc_entity_generic_id)
-> SemIR::InstId {
const auto& generic = context.generics().Get(assoc_entity_generic_id);
auto bindings = context.inst_blocks().Get(generic.bindings_id);
auto interface_args_id =
context.specifics().GetArgsOrEmpty(interface_specific_id);
auto interface_args = context.inst_blocks().Get(interface_args_id);
// The `Self` binding is the first binding after the interface's arguments.
auto self_binding_id = bindings[interface_args.size()];
// Check that we found the self binding. The binding might be a
// `SymbolicBinding` or an `ImportRef` naming one.
auto self_binding_const_inst_id =
context.constant_values().GetConstantInstId(self_binding_id);
auto bind_name_inst =
context.insts().GetAs<SemIR::SymbolicBinding>(self_binding_const_inst_id);
CARBON_CHECK(
context.entity_names().Get(bind_name_inst.entity_name_id).name_id ==
SemIR::NameId::SelfType,
"Expected a Self binding, found {0}", bind_name_inst);
return self_binding_id;
}
// Construct a facet value that can be used for the `Self` binding of entities
// inside an interface.
//
// The `interface_specific_id` is the specific of the interface around the
// `Self`. The `generic_id` is for member of the interface that the `Self` value
// will be for. The `self_witness_id` is an impl witness for the interface that
// the `self_type_id` implements that interface. It should come from an impl
// definition with the given self-type and the interface as its constraint.
//
// The returned facet value can be used as the `Self` value in a specific for
// the generic member of the interface, and can appear in its specific. As such,
// this is a building block of GetSelfSpecificForInterfaceMemberWithSelfType.
static auto GetSelfFacetValueForInterfaceMemberSpecific(
Context& context, SemIR::SpecificId interface_specific_id,
SemIR::GenericId generic_id, SemIR::TypeId self_type_id,
SemIR::InstId self_witness_id) -> SemIR::InstId {
auto self_binding_id =
GetSelfBinding(context, interface_specific_id, generic_id);
auto self_facet_type_id = SemIR::GetTypeOfInstInSpecific(
context.sem_ir(), interface_specific_id, self_binding_id);
// Create a facet value to be the value of `Self` in the interface.
// TODO: Pass this in instead of creating it here. The caller sometimes
// already has a facet value.
auto type_inst_id = context.types().GetTypeInstId(self_type_id);
auto witnesses_block_id =
context.inst_blocks().AddCanonical({self_witness_id});
auto self_value_const_id = TryEvalInst(
context, SemIR::FacetValue{.type_id = self_facet_type_id,
.type_inst_id = type_inst_id,
.witnesses_block_id = witnesses_block_id});
return context.constant_values().GetInstId(self_value_const_id);
}
// Builds and returns the argument list from `interface_specific_id` with a
// value for the `Self` parameter of `generic_id` appended.
static auto GetGenericArgsWithSelfType(Context& context,
SemIR::SpecificId interface_specific_id,
SemIR::GenericId generic_id,
SemIR::TypeId self_type_id,
SemIR::InstId witness_inst_id,
std::size_t reserve_args_size = 0)
-> llvm::SmallVector<SemIR::InstId> {
auto interface_args_id =
context.specifics().GetArgsOrEmpty(interface_specific_id);
auto interface_args = context.inst_blocks().Get(interface_args_id);
llvm::SmallVector<SemIR::InstId> arg_ids;
arg_ids.reserve(std::max(reserve_args_size, interface_args.size() + 1));
// Start with the enclosing arguments from the interface.
llvm::append_range(arg_ids, interface_args);
// Add the `Self` argument.
arg_ids.push_back(GetSelfFacetValueForInterfaceMemberSpecific(
context, interface_specific_id, generic_id, self_type_id,
witness_inst_id));
return arg_ids;
}
auto GetSelfSpecificForInterfaceMemberWithSelfType(
Context& context, SemIR::LocId loc_id,
SemIR::SpecificId interface_specific_id, SemIR::GenericId generic_id,
SemIR::SpecificId enclosing_specific_id, SemIR::TypeId self_type_id,
SemIR::InstId witness_inst_id) -> SemIR::SpecificId {
SemIR::SpecificId interface_with_self_specific_id,
SemIR::GenericId generic_id, SemIR::SpecificId enclosing_specific_id)
-> SemIR::SpecificId {
const auto& generic = context.generics().Get(generic_id);
auto self_specific_args = context.inst_blocks().Get(
context.specifics().Get(generic.self_specific_id).args_id);
auto arg_ids = GetGenericArgsWithSelfType(
context, interface_specific_id, generic_id, self_type_id, witness_inst_id,
self_specific_args.size());
auto arg_ids = llvm::SmallVector<SemIR::InstId>(context.inst_blocks().Get(
context.specifics().GetArgsOrEmpty(interface_with_self_specific_id)));
// Determine the number of specific arguments that enclose the point where
// this self specific will be used from. In an impl, this will be the number
@@ -189,12 +100,9 @@ auto GetSelfSpecificForInterfaceMemberWithSelfType(
return MakeSpecific(context, loc_id, generic_id, arg_ids);
}
auto GetTypeForSpecificAssociatedEntity(Context& context, SemIR::LocId loc_id,
SemIR::SpecificId interface_specific_id,
SemIR::InstId decl_id,
SemIR::TypeId self_type_id,
SemIR::InstId self_witness_id)
-> SemIR::TypeId {
auto GetTypeForSpecificAssociatedEntity(
Context& context, SemIR::SpecificId interface_with_self_specific_id,
SemIR::InstId decl_id) -> SemIR::TypeId {
auto decl_constant_inst_id =
context.constant_values().GetConstantInstId(decl_id);
if (decl_constant_inst_id == SemIR::ErrorInst::InstId) {
@@ -203,28 +111,19 @@ auto GetTypeForSpecificAssociatedEntity(Context& context, SemIR::LocId loc_id,
auto decl = context.insts().Get(decl_constant_inst_id);
if (auto assoc_const = decl.TryAs<SemIR::AssociatedConstantDecl>()) {
// Form a specific for the associated constant, and grab the type from
// there.
auto generic_id = context.associated_constants()
.Get(assoc_const->assoc_const_id)
.generic_id;
auto arg_ids =
GetGenericArgsWithSelfType(context, interface_specific_id, generic_id,
self_type_id, self_witness_id);
auto const_specific_id = MakeSpecific(context, loc_id, generic_id, arg_ids);
return SemIR::GetTypeOfInstInSpecific(context.sem_ir(), const_specific_id,
decl_id);
return SemIR::GetTypeOfInstInSpecific(
context.sem_ir(), interface_with_self_specific_id, decl_id);
}
if (auto fn = context.types().TryGetAs<SemIR::FunctionType>(decl.type_id())) {
// Form the type of the function within the interface, and attach the `Self`
// type.
auto interface_fn_type_id = SemIR::GetTypeOfInstInSpecific(
context.sem_ir(), interface_specific_id, decl_id);
auto self_facet_id = GetSelfFacetValueForInterfaceMemberSpecific(
context, interface_specific_id,
context.functions().Get(fn->function_id).generic_id, self_type_id,
self_witness_id);
context.sem_ir(), interface_with_self_specific_id, decl_id);
auto self_facet_id = context.inst_blocks()
.Get(context.specifics().GetArgsOrEmpty(
interface_with_self_specific_id))
.back();
return GetFunctionTypeWithSelfType(
context, context.types().GetTypeInstId(interface_fn_type_id),
self_facet_id);
@@ -233,9 +132,11 @@ auto GetTypeForSpecificAssociatedEntity(Context& context, SemIR::LocId loc_id,
CARBON_FATAL("Unexpected kind for associated constant {0}", decl);
}
auto AddSelfGenericParameter(Context& context, SemIR::LocId definition_loc_id,
SemIR::TypeId type_id, SemIR::NameScopeId scope_id,
bool is_template) -> SemIR::InstId {
auto AddSelfSymbolicBindingToScope(Context& context,
SemIR::LocId definition_loc_id,
SemIR::TypeId type_id,
SemIR::NameScopeId scope_id,
bool is_template) -> SemIR::InstId {
auto entity_name_id = context.entity_names().AddSymbolicBindingName(
SemIR::NameId::SelfType, scope_id,
context.scope_stack().AddCompileTimeBinding(), is_template);
@@ -246,7 +147,6 @@ auto AddSelfGenericParameter(Context& context, SemIR::LocId definition_loc_id,
{.type_id = type_id,
.entity_name_id = entity_name_id,
.value_id = SemIR::InstId::None});
context.scope_stack().PushCompileTimeBinding(self_param_inst_id);
context.name_scopes().AddRequiredName(scope_id, SemIR::NameId::SelfType,
self_param_inst_id);
return self_param_inst_id;