mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-09-24 22:02:23 +01:00
Geoff Romer
bf45b1cbf5
This separates the return type from the return pattern, and replaces the return pattern with a block of return patterns. This is a step toward support for `ref` returns (where there's no corresponding return pattern) and compund-form returns (where there may be multiple return patterns).
377 lines
16 KiB
C++
377 lines
16 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#include "toolchain/check/call.h"
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#include <optional>
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#include "toolchain/base/kind_switch.h"
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#include "toolchain/check/context.h"
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#include "toolchain/check/control_flow.h"
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#include "toolchain/check/convert.h"
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#include "toolchain/check/cpp/call.h"
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#include "toolchain/check/cpp/thunk.h"
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#include "toolchain/check/deduce.h"
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#include "toolchain/check/facet_type.h"
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#include "toolchain/check/function.h"
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#include "toolchain/check/import_ref.h"
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#include "toolchain/check/inst.h"
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#include "toolchain/check/name_ref.h"
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#include "toolchain/check/thunk.h"
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#include "toolchain/check/type.h"
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#include "toolchain/diagnostics/format_providers.h"
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#include "toolchain/sem_ir/builtin_function_kind.h"
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#include "toolchain/sem_ir/entity_with_params_base.h"
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#include "toolchain/sem_ir/function.h"
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#include "toolchain/sem_ir/ids.h"
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#include "toolchain/sem_ir/inst.h"
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#include "toolchain/sem_ir/typed_insts.h"
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namespace Carbon::Check {
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namespace {
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// Entity kinds, for diagnostics. Converted to an int for a select.
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enum class EntityKind : uint8_t {
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Function = 0,
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GenericClass = 1,
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GenericInterface = 2,
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GenericNamedConstraint = 3,
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};
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} // namespace
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// Resolves the callee expression in a call to a specific callee, or diagnoses
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// if no specific callee can be identified. This verifies the arity of the
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// callee and determines any compile-time arguments, but doesn't check that the
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// runtime arguments are convertible to the parameter types.
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//
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// `self_id` and `arg_ids` are the self argument and explicit arguments in the
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// call.
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//
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// Returns a `SpecificId` for the specific callee, `SpecificId::None` if the
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// callee is not generic, or `nullopt` if an error has been diagnosed.
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static auto ResolveCalleeInCall(Context& context, SemIR::LocId loc_id,
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const SemIR::EntityWithParamsBase& entity,
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EntityKind entity_kind_for_diagnostic,
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SemIR::SpecificId enclosing_specific_id,
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SemIR::InstId self_type_id,
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SemIR::InstId self_id,
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llvm::ArrayRef<SemIR::InstId> arg_ids)
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-> std::optional<SemIR::SpecificId> {
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// Check that the arity matches.
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auto params = context.inst_blocks().GetOrEmpty(entity.param_patterns_id);
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if (arg_ids.size() != params.size()) {
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CARBON_DIAGNOSTIC(CallArgCountMismatch, Error,
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"{0} argument{0:s} passed to "
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"{1:=0:function|=1:generic class|=2:generic "
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"interface|=3:generic constraint}"
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" expecting {2} argument{2:s}",
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Diagnostics::IntAsSelect, Diagnostics::IntAsSelect,
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Diagnostics::IntAsSelect);
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CARBON_DIAGNOSTIC(InCallToEntity, Note,
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"calling {0:=0:function|=1:generic class|=2:generic "
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"interface|=3:generic constraint}"
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" declared here",
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Diagnostics::IntAsSelect);
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context.emitter()
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.Build(loc_id, CallArgCountMismatch, arg_ids.size(),
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static_cast<int>(entity_kind_for_diagnostic), params.size())
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.Note(entity.latest_decl_id(), InCallToEntity,
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static_cast<int>(entity_kind_for_diagnostic))
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.Emit();
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return std::nullopt;
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}
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// Perform argument deduction.
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auto specific_id = SemIR::SpecificId::None;
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if (entity.generic_id.has_value()) {
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specific_id = DeduceGenericCallArguments(
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context, loc_id, entity.generic_id, enclosing_specific_id, self_type_id,
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entity.implicit_param_patterns_id, entity.param_patterns_id, self_id,
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arg_ids);
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if (!specific_id.has_value()) {
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return std::nullopt;
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}
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}
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return specific_id;
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}
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// Performs a call where the callee is the name of a generic class, such as
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// `Vector(i32)`.
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static auto PerformCallToGenericClass(Context& context, SemIR::LocId loc_id,
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SemIR::ClassId class_id,
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SemIR::SpecificId enclosing_specific_id,
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llvm::ArrayRef<SemIR::InstId> arg_ids)
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-> SemIR::InstId {
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const auto& generic_class = context.classes().Get(class_id);
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auto callee_specific_id =
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ResolveCalleeInCall(context, loc_id, generic_class,
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EntityKind::GenericClass, enclosing_specific_id,
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/*self_type_id=*/SemIR::InstId::None,
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/*self_id=*/SemIR::InstId::None, arg_ids);
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if (!callee_specific_id) {
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return SemIR::ErrorInst::InstId;
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}
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return GetOrAddInst<SemIR::ClassType>(context, loc_id,
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{.type_id = SemIR::TypeType::TypeId,
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.class_id = class_id,
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.specific_id = *callee_specific_id});
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}
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static auto EntityFromInterfaceOrNamedConstraint(
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Context& context, SemIR::InterfaceId interface_id)
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-> const SemIR::EntityWithParamsBase& {
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return context.interfaces().Get(interface_id);
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}
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static auto EntityFromInterfaceOrNamedConstraint(
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Context& context, SemIR::NamedConstraintId named_constraint_id)
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-> const SemIR::EntityWithParamsBase& {
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return context.named_constraints().Get(named_constraint_id);
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}
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// Performs a call where the callee is the name of a generic interface or named
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// constraint, such as `AddWith(i32)`.
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template <typename IdT>
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requires SameAsOneOf<IdT, SemIR::InterfaceId, SemIR::NamedConstraintId>
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static auto PerformCallToGenericInterfaceOrNamedConstaint(
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Context& context, SemIR::LocId loc_id, IdT id,
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SemIR::SpecificId enclosing_specific_id,
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llvm::ArrayRef<SemIR::InstId> arg_ids) -> SemIR::InstId {
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const auto& entity = EntityFromInterfaceOrNamedConstraint(context, id);
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auto entity_kind_for_diagnostic = EntityKind::GenericInterface;
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if constexpr (std::same_as<IdT, SemIR::NamedConstraintId>) {
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entity_kind_for_diagnostic = EntityKind::GenericNamedConstraint;
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}
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auto callee_specific_id =
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ResolveCalleeInCall(context, loc_id, entity, entity_kind_for_diagnostic,
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enclosing_specific_id,
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/*self_type_id=*/SemIR::InstId::None,
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/*self_id=*/SemIR::InstId::None, arg_ids);
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if (!callee_specific_id) {
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return SemIR::ErrorInst::InstId;
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}
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std::optional<SemIR::FacetType> facet_type;
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if constexpr (std::same_as<IdT, SemIR::InterfaceId>) {
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facet_type = FacetTypeFromInterface(context, id, *callee_specific_id);
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} else {
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facet_type = FacetTypeFromNamedConstraint(context, id, *callee_specific_id);
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}
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return GetOrAddInst(context, loc_id, *facet_type);
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}
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// Builds an appropriate specific function for the callee, also handling
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// instance binding.
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static auto BuildCalleeSpecificFunction(
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Context& context, SemIR::LocId loc_id, SemIR::InstId callee_id,
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SemIR::InstId callee_function_self_type_id,
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SemIR::SpecificId callee_specific_id) -> SemIR::InstId {
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auto generic_callee_id = callee_id;
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// Strip off a bound_method so that we can form a constant specific callee.
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auto bound_method = context.insts().TryGetAs<SemIR::BoundMethod>(callee_id);
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if (bound_method) {
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generic_callee_id = bound_method->function_decl_id;
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}
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// Form a specific callee.
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if (callee_function_self_type_id.has_value()) {
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// This is an associated function in an interface; the callee is the
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// specific function in the impl that corresponds to the specific function
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// we deduced.
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callee_id =
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GetOrAddInst(context, SemIR::LocId(generic_callee_id),
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SemIR::SpecificImplFunction{
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.type_id = GetSingletonType(
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context, SemIR::SpecificFunctionType::TypeInstId),
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.callee_id = generic_callee_id,
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.specific_id = callee_specific_id});
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} else {
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// This is a regular generic function. The callee is the specific function
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// we deduced.
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callee_id =
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GetOrAddInst(context, SemIR::LocId(generic_callee_id),
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SemIR::SpecificFunction{
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.type_id = GetSingletonType(
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context, SemIR::SpecificFunctionType::TypeInstId),
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.callee_id = generic_callee_id,
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.specific_id = callee_specific_id});
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}
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// Add the `self` argument back if there was one.
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if (bound_method) {
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callee_id =
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GetOrAddInst<SemIR::BoundMethod>(context, loc_id,
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{.type_id = bound_method->type_id,
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.object_id = bound_method->object_id,
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.function_decl_id = callee_id});
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}
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return callee_id;
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}
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// Returns the return type, with a scoped annotation for any diagnostics.
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static auto CheckCalleeFunctionReturnType(Context& context, SemIR::LocId loc_id,
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SemIR::FunctionId callee_function_id,
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SemIR::SpecificId callee_specific_id)
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-> SemIR::ReturnTypeInfo {
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auto& function = context.functions().Get(callee_function_id);
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Diagnostics::AnnotationScope annotate_diagnostics(
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&context.emitter(), [&](auto& builder) {
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CARBON_DIAGNOSTIC(IncompleteReturnTypeHere, Note,
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"return type declared here");
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builder.Note(function.return_type_inst_id, IncompleteReturnTypeHere);
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});
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return CheckFunctionReturnType(context, loc_id, function, callee_specific_id);
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}
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auto PerformCallToFunction(Context& context, SemIR::LocId loc_id,
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SemIR::InstId callee_id,
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const SemIR::CalleeFunction& callee_function,
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llvm::ArrayRef<SemIR::InstId> arg_ids)
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-> SemIR::InstId {
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// If the callee is a generic function, determine the generic argument values
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// for the call.
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auto callee_specific_id = ResolveCalleeInCall(
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context, loc_id, context.functions().Get(callee_function.function_id),
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EntityKind::Function, callee_function.enclosing_specific_id,
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callee_function.self_type_id, callee_function.self_id, arg_ids);
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if (!callee_specific_id) {
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return SemIR::ErrorInst::InstId;
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}
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if (callee_specific_id->has_value()) {
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callee_id = BuildCalleeSpecificFunction(context, loc_id, callee_id,
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callee_function.self_type_id,
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*callee_specific_id);
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}
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// If there is a return slot, build storage for the result.
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SemIR::ReturnTypeInfo return_info = CheckCalleeFunctionReturnType(
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context, loc_id, callee_function.function_id, *callee_specific_id);
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SemIR::InstId return_slot_arg_id = SemIR::InstId::None;
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switch (return_info.init_repr.kind) {
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case SemIR::InitRepr::InPlace:
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case SemIR::InitRepr::Dependent:
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// Tentatively put storage for a temporary in the function's return slot.
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// This will be replaced if necessary when we perform initialization.
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return_slot_arg_id = AddInst<SemIR::TemporaryStorage>(
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context, loc_id, {.type_id = return_info.type_id});
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break;
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case SemIR::InitRepr::None:
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// For functions with an implicit return type, the return type is the
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// empty tuple type.
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if (!return_info.type_id.has_value()) {
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return_info.type_id = GetTupleType(context, {});
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}
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break;
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case SemIR::InitRepr::ByCopy:
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break;
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case SemIR::InitRepr::Incomplete:
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// Don't form an initializing expression with an incomplete type.
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// CheckFunctionReturnType will have diagnosed this for us if needed.
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return_info.type_id = SemIR::ErrorInst::TypeId;
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break;
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}
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auto& callee = context.functions().Get(callee_function.function_id);
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// Convert the arguments to match the parameters.
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auto converted_args_id =
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ConvertCallArgs(context, loc_id, callee_function.self_id, arg_ids,
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return_slot_arg_id, callee, *callee_specific_id);
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switch (callee.special_function_kind) {
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case SemIR::Function::SpecialFunctionKind::Thunk: {
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// If we're about to form a direct call to a thunk, inline it.
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LoadImportRef(context, callee.thunk_decl_id());
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// Name the thunk target within the enclosing scope of the thunk.
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auto thunk_ref_id =
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BuildNameRef(context, loc_id, callee.name_id, callee.thunk_decl_id(),
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callee_function.enclosing_specific_id);
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// This recurses back into `PerformCall`. However, we never form a thunk
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// to a thunk, so we only recurse once.
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return PerformThunkCall(context, loc_id, callee_function.function_id,
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context.inst_blocks().Get(converted_args_id),
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thunk_ref_id);
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}
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case SemIR::Function::SpecialFunctionKind::HasCppThunk: {
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return PerformCppThunkCall(context, loc_id, callee_function.function_id,
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context.inst_blocks().Get(converted_args_id),
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callee.cpp_thunk_decl_id());
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}
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case SemIR::Function::SpecialFunctionKind::None:
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case SemIR::Function::SpecialFunctionKind::Builtin: {
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return GetOrAddInst<SemIR::Call>(context, loc_id,
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{.type_id = return_info.type_id,
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.callee_id = callee_id,
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.args_id = converted_args_id});
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}
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}
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}
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// Performs a call where the callee is a generic type. If it's not a generic
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// type, produces a diagnostic.
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static auto PerformCallToNonFunction(Context& context, SemIR::LocId loc_id,
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SemIR::InstId callee_id,
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llvm::ArrayRef<SemIR::InstId> arg_ids)
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-> SemIR::InstId {
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auto type_inst =
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context.types().GetAsInst(context.insts().Get(callee_id).type_id());
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CARBON_KIND_SWITCH(type_inst) {
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case CARBON_KIND(SemIR::GenericClassType generic_class): {
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return PerformCallToGenericClass(context, loc_id, generic_class.class_id,
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generic_class.enclosing_specific_id,
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arg_ids);
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}
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case CARBON_KIND(SemIR::GenericInterfaceType generic_interface): {
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return PerformCallToGenericInterfaceOrNamedConstaint(
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context, loc_id, generic_interface.interface_id,
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generic_interface.enclosing_specific_id, arg_ids);
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}
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case CARBON_KIND(SemIR::GenericNamedConstraintType generic_constraint): {
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return PerformCallToGenericInterfaceOrNamedConstaint(
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context, loc_id, generic_constraint.named_constraint_id,
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generic_constraint.enclosing_specific_id, arg_ids);
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}
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default: {
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CARBON_DIAGNOSTIC(CallToNonCallable, Error,
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"value of type {0} is not callable", TypeOfInstId);
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context.emitter().Emit(loc_id, CallToNonCallable, callee_id);
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return SemIR::ErrorInst::InstId;
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}
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}
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}
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auto PerformCall(Context& context, SemIR::LocId loc_id, SemIR::InstId callee_id,
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llvm::ArrayRef<SemIR::InstId> arg_ids) -> SemIR::InstId {
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// Try treating the callee as a function first.
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auto callee = GetCallee(context.sem_ir(), callee_id);
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CARBON_KIND_SWITCH(callee) {
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case CARBON_KIND(SemIR::CalleeError _): {
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return SemIR::ErrorInst::InstId;
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}
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case CARBON_KIND(SemIR::CalleeFunction fn): {
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context.ref_tags().Insert(fn.self_id, Context::RefTag::NotRequired);
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return PerformCallToFunction(context, loc_id, callee_id, fn, arg_ids);
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}
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case CARBON_KIND(SemIR::CalleeNonFunction _): {
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return PerformCallToNonFunction(context, loc_id, callee_id, arg_ids);
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}
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case CARBON_KIND(SemIR::CalleeCppOverloadSet overload): {
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context.ref_tags().Insert(overload.self_id, Context::RefTag::NotRequired);
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return PerformCallToCppFunction(context, loc_id,
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overload.cpp_overload_set_id,
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overload.self_id, arg_ids);
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}
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}
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}
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} // namespace Carbon::Check
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