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carbon-lang/toolchain/check/impl.h
T
Dana Jansens 6a0a1f3e85 Plumb through IdentifiedFacetTypeId in impl checking (#7924)
We plumb the IdentifiedFacetTypeId through instead of identifying the
constraint twice, even though the second one should result in a cache
hit, as this makes things more clear and explicit.

Also a few other smaller cleanups and comments around forming the facet
type and identifying it, that I am trying to pull out of a much larger
change to identifying, so as to reduce noise there.
2026-10-13 13:41:15 +00:00

117 lines
5.4 KiB
C++

// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#ifndef CARBON_TOOLCHAIN_CHECK_IMPL_H_
#define CARBON_TOOLCHAIN_CHECK_IMPL_H_
#include "toolchain/check/context.h"
#include "toolchain/sem_ir/ids.h"
#include "toolchain/sem_ir/specific_interface.h"
namespace Carbon::Check {
struct RedeclaredImpl {
// The previous Impl which the query Impl is redeclaring.
SemIR::ImplId prev_impl_id;
};
struct NewImpl {
// The lookup bucket for the query Impl where it should be added once an
// ImplId is known.
SemIR::ImplStore::LookupBucketRef lookup_bucket;
// Indicates the query Impl is not a redeclaration but an error was diagnosed.
// The caller should avoid diagnosing more errors in the query impl.
bool find_had_error;
};
// Finds an existing impl if the `query_impl` is a redeclaration, and returns
// its `ImplId`. This ensures all (valid) redeclarations share the same
// `ImplId`. Otherwise, returns the bucket where a new `ImplId` should be added.
auto FindImplId(Context& context, const SemIR::Impl& query_impl)
-> std::variant<RedeclaredImpl, NewImpl>;
// Adds an impl to the ImplStore, and returns a new `ImplId`.
//
// If the impl is modified with `extend` then the parent's scope is extended
// with it.
auto AddImpl(Context& context, const SemIR::Impl& impl,
SemIR::ImplStore::LookupBucketRef lookup_bucket,
Parse::NodeId extend_node, SemIR::LocId implicit_params_loc_id)
-> SemIR::ImplId;
// Creates and returns an impl witness instruction for an impl declaration.
//
// If there are no rewrites into a name of the interface being implemented, a
// placeholder witness table is created, to be replaced in the impl definition.
//
// Adds and returns an `ImplWitness` instruction (created with location set to
// `loc_id`) that shows the "`Self` type" (from a facet in `impl.self_id`)
// implements an identified interface (from a facet type in
// `impl.constraint_id`). This witness reflects the values assigned to
// associated constant members of that interface by rewrite constraints in the
// constraint facet type. `self_specific_id` will be the `specific_id` of the
// resulting witness.
auto AddImplWitnessForDeclaration(Context& context, SemIR::LocId loc_id,
SemIR::LocId constraint_loc_id,
const SemIR::Impl& impl,
SemIR::IdentifiedFacetTypeId identified_id,
SemIR::SpecificId self_specific_id)
-> SemIR::InstId;
// Update `impl`'s witness at the start of a definition.
auto ImplWitnessStartDefinition(Context& context, SemIR::Impl& impl) -> void;
// Adds the function members to the witness for `impl`.
auto FinishImplWitness(Context& context, const SemIR::Impl& impl_id) -> void;
// Checks that any `require` declarations in the interface being implemented by
// `impl` are satisfied. Otherwise, a diagnostic is issued and the `impl` is
// made invalid.
auto CheckRequireDeclsSatisfied(Context& context, SemIR::LocId loc_id,
SemIR::Impl& impl,
SemIR::TypeInstId full_constraint_id,
SemIR::IdentifiedFacetTypeId identified_id)
-> void;
// Sets all unset members of the witness for `impl` to the error instruction and
// sets the witness id in the `Impl` to an error.
auto FillImplWitnessWithErrors(Context& context, SemIR::Impl& impl) -> void;
// Returns whether the impl is either `final` explicitly, or implicitly due to
// being concrete.
auto IsImplEffectivelyFinal(Context& context, const SemIR::Impl& impl) -> bool;
// Checks that `impl_function_id` is a valid implementation of the function
// described in the interface as `interface_function_id`. Returns the value to
// put into the corresponding slot in the witness table, which can be
// `ErrorInst::InstId` if the function is not usable.
auto CheckAssociatedFunctionImplementation(
Context& context, SemIR::FunctionType interface_function_type,
SemIR::SpecificId enclosing_specific_id, SemIR::InstId impl_decl_id,
bool defer_thunk_definition) -> SemIR::InstId;
// Checks that the constraint specified for the impl is a facet type. Returns
// false if an error was diagnosed.
auto CheckConstraintIsFacetType(Context& context, SemIR::LocId loc_id,
SemIR::TypeInstId constraint_id) -> bool;
// Checks that the constraint specified for the impl is a valid, identified
// facet type that extends a single interface. Returns the IdentifiedFacetType
// which contains the interface that the impl implements. On error, issues a
// diagnostic and returns `None`.
auto CheckConstraintIsInterface(Context& context, SemIR::LocId loc_id,
SemIR::InstId self_id,
SemIR::TypeInstId full_constraint_id)
-> SemIR::IdentifiedFacetTypeId;
// Given a specific for the impl, returns the specific interface that the impl
// declaration is implementing. Returns None in the case of an error being
// diagnosed while constructing the specific interface.
auto GetImplInterfaceInSpecific(Context& context, const SemIR::Impl& impl,
SemIR::SpecificId specific_id)
-> SemIR::SpecificInterface;
} // namespace Carbon::Check
#endif // CARBON_TOOLCHAIN_CHECK_IMPL_H_