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Code Issues Packages Projects Releases 10 Wiki Activity

Teach comparison interfaces about C++ operators (#7163)

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This commit is contained in:
Christopher Di Bella
2026-05-10 21:54:50 +00:00
committed by GitHub
parent 7c44c4dfb0
commit 219d1cdee1
7 changed files with 3175 additions and 0 deletions
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toolchain/check/cpp/impl_lookup.cpp
+63
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@@ -19,6 +19,7 @@
#include "toolchain/check/type.h"
#include "toolchain/check/type_completion.h"
#include "toolchain/sem_ir/builtin_function_kind.h"
#include "toolchain/sem_ir/core_interface.h"
#include "toolchain/sem_ir/ids.h"
#include "toolchain/sem_ir/typed_insts.h"
@@ -301,6 +302,57 @@ static auto BuildCppBinaryOperatorWitness(
query_specific_interface_id, {fn_id});
}
static auto BuildCppComparisonWitness(
Context& context, SemIR::LocId loc_id, CoreIdentifier interface,
llvm::ArrayRef<CoreIdentifier> operator_names,
SemIR::ConstantId query_self_const_id,
SemIR::SpecificInterfaceId query_specific_interface_id) -> SemIR::InstId {
auto self_type_id =
context.types().GetTypeIdForTypeConstantId(query_self_const_id);
auto args =
context.inst_blocks().Get(context.specifics()
.Get(context.specific_interfaces()
.Get(query_specific_interface_id)
.specific_id)
.args_id);
CARBON_CHECK(args.size() == 1, "Binary operator missing an argument");
auto arg_type_id = context.types().GetTypeIdForTypeInstId(args[0]);
auto operators = llvm::SmallVector<SemIR::InstId, 4>();
for (auto operator_name : operator_names) {
auto lookup_id = LookupCppOperator(
context, loc_id,
{.interface_name = interface, .op_name = operator_name},
{self_type_id, arg_type_id});
if (lookup_id == SemIR::ErrorInst::InstId ||
lookup_id == SemIR::InstId::None) {
// `T.(Core.EqWith(U))` is only valid if both `t == u` and `t != u` are
// valid expressions. Looking for `t != u` is pointless if we're unable to
// find a valid `t == u`, because `t != u` won't provide further useful
// information at this point.
//
// The behavior is dependent on which expression is checked first: no
// diagnostic will be emitted for an erroneous `operator!=` if lookup for
// `operator==` produces `SemIR::InstId::None`.
return lookup_id;
}
auto return_type_id = context.functions()
.Get(context.insts()
.GetAs<SemIR::FunctionDecl>(lookup_id)
.function_id)
.return_type_inst_id;
if (!return_type_id.has_value()) {
return SemIR::InstId::None;
}
operators.push_back(lookup_id);
}
return BuildCustomWitness(context, loc_id, query_self_const_id,
query_specific_interface_id, operators);
}
auto LookupCppImpl(Context& context, SemIR::LocId loc_id,
SemIR::CoreInterface core_interface,
SemIR::ConstantId query_self_const_id,
@@ -341,6 +393,17 @@ auto LookupCppImpl(Context& context, SemIR::LocId loc_id,
/*has_associated_result_type=*/false,
query_self_const_id,
query_specific_interface_id);
case SemIR::CoreInterface::EqWith:
return BuildCppComparisonWitness(
context, loc_id, CoreIdentifier::EqWith,
{CoreIdentifier::Equal, CoreIdentifier::NotEqual},
query_self_const_id, query_specific_interface_id);
case SemIR::CoreInterface::OrderedWith:
return BuildCppComparisonWitness(
context, loc_id, CoreIdentifier::OrderedWith,
{CoreIdentifier::Less, CoreIdentifier::LessOrEquivalent,
CoreIdentifier::Greater, CoreIdentifier::GreaterOrEquivalent},
query_self_const_id, query_specific_interface_id);
case SemIR::CoreInterface::Copy:
return BuildCopyWitness(context, loc_id, query_self_const_id,
query_specific_interface_id);