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Consolidate checking for and rejecting other_requirements in impl lookup (#7518)

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Since the introduction of `other_requirements`, we now have a dedicated
step in impl lookup for checking that the requirements of the query
facet type are satisfied. That is the place where we will be checking
same-type constraints, which `other_requirements` signals the presence
of.

Consolidate all checking of `other_requirements` to that step, which
reduces our use of `FacetTypeInfo` (as opposed to the
`IdentifiedFacetType`) and removes interest in same-type constraints
from code that is not related to them.
This commit is contained in:
Dana Jansens
2026-07-16 18:09:46 +00:00
committed by GitHub
parent 625f2ca629
commit b3e9dd3ea2
1 changed files with 7 additions and 25 deletions
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toolchain/check/impl_lookup.cpp
+7 -25
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@@ -203,25 +203,15 @@ static auto FindAndDiagnoseImplLookupCycle(
return false;
}
struct RequiredImplsFromConstraint {
llvm::ArrayRef<SemIR::IdentifiedFacetType::RequiredImpl> req_impls;
bool other_requirements;
};
// Gets the set of `SpecificInterface`s that are required by a facet type
// (as a constant value), and any special requirements.
static auto GetRequiredImplsFromConstraint(
Context& context, SemIR::LocId loc_id,
SemIR::ConstantId query_self_const_id,
SemIR::ConstantId query_facet_type_const_id, bool diagnose)
-> std::optional<RequiredImplsFromConstraint> {
-> std::optional<llvm::ArrayRef<SemIR::IdentifiedFacetType::RequiredImpl>> {
auto facet_type_inst_id =
context.types().GetTypeInstIdForTypeConstantId(query_facet_type_const_id);
auto facet_type_inst =
context.insts().GetAs<SemIR::FacetType>(facet_type_inst_id);
const auto& facet_type_info =
context.facet_types().Get(facet_type_inst.facet_type_id);
auto identified_id = RequireIdentifiedFacetType(
context, loc_id, query_self_const_id, facet_type_inst_id,
[&](auto& builder) {
@@ -234,10 +224,7 @@ static auto GetRequiredImplsFromConstraint(
if (!identified_id.has_value()) {
return std::nullopt;
}
return {
{.req_impls =
context.identified_facet_types().Get(identified_id).required_impls(),
.other_requirements = facet_type_info.other_requirements}};
return context.identified_facet_types().Get(identified_id).required_impls();
}
static auto TreatImplAsFinal(Context& context, const SemIR::Impl& impl)
@@ -304,10 +291,6 @@ static auto TryGetSpecificWitnessIdForImpl(
CARBON_CHECK(deduced_constraint_facet_type_info.extend_constraints.size() ==
1);
if (deduced_constraint_facet_type_info.other_requirements) {
return SemIR::ConstantId::None;
}
// The specifics in the queried interface must match the deduced specifics in
// the impl's constraint facet type.
auto impl_interface_specific_id =
@@ -558,6 +541,9 @@ static auto VerifyQueryFacetTypeConstraints(
// TODO: Validate that the witnesses satisfy the other requirements in the
// `facet_type_info`.
if (facet_type_info.other_requirements) {
return false;
}
return true;
}
@@ -1002,14 +988,10 @@ auto LookupImplWitness(Context& context, SemIR::LocId loc_id,
auto req_impls_from_constraint =
GetRequiredImplsFromConstraint(context, loc_id, query_self_const_id,
query_facet_type_const_id, diagnose);
if (!req_impls_from_constraint) {
if (!req_impls_from_constraint.has_value()) {
return SemIR::InstBlockIdOrError::MakeError();
}
auto [req_impls, other_requirements] = *req_impls_from_constraint;
if (other_requirements) {
// TODO: Remove this when other requirements go away.
return SemIR::InstBlockId::None;
}
auto req_impls = *req_impls_from_constraint;
if (req_impls.empty()) {
return SemIR::InstBlockId::Empty;
}