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carbon-lang/toolchain/check/handle_alias.cpp
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3.2 KiB
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// 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
#include "toolchain/check/context.h"
#include "toolchain/check/handle.h"
#include "toolchain/check/modifiers.h"
#include "toolchain/check/name_component.h"
#include "toolchain/parse/node_ids.h"
#include "toolchain/sem_ir/ids.h"
#include "toolchain/sem_ir/typed_insts.h"
namespace Carbon::Check {
auto HandleParseNode(Context& context, Parse::AliasIntroducerId /*node_id*/)
-> bool {
context.decl_introducer_state_stack().Push<Lex::TokenKind::Alias>();
context.decl_name_stack().PushScopeAndStartName();
// Push a pattern block to handle parameters of the alias declaration.
// TODO: Disallow these in parse, instead of check, so we don't have to do
// this.
context.pattern_block_stack().Push();
return true;
}
auto HandleParseNode(Context& /*context*/,
Parse::AliasInitializerId /*node_id*/) -> bool {
return true;
}
auto HandleParseNode(Context& context, Parse::AliasId /*node_id*/) -> bool {
auto [expr_node, expr_id] = context.node_stack().PopExprWithNodeId();
auto name_context = context.decl_name_stack().FinishName(
PopNameComponentWithoutParams(context, Lex::TokenKind::Alias));
auto introducer =
context.decl_introducer_state_stack().Pop<Lex::TokenKind::Alias>();
LimitModifiersOnDecl(context, introducer, KeywordModifierSet::Access);
auto entity_name_id = context.entity_names().Add(
{.name_id = name_context.name_id_for_new_inst(),
.parent_scope_id = name_context.parent_scope_id,
.bind_index = SemIR::CompileTimeBindIndex::Invalid});
auto alias_type_id = SemIR::TypeId::Invalid;
auto alias_value_id = SemIR::InstId::Invalid;
if (SemIR::IsSingletonInstId(expr_id)) {
// Type (`bool`) and value (`false`) literals provided by the builtin
// structure should be turned into name references.
// TODO: Look into handling `false`, this doesn't do it right now because it
// sees a value instruction instead of a builtin.
alias_type_id = context.insts().Get(expr_id).type_id();
alias_value_id = expr_id;
} else if (auto inst = context.insts().TryGetAs<SemIR::NameRef>(expr_id)) {
// Pass through name references, albeit changing the name in use.
alias_type_id = inst->type_id;
alias_value_id = inst->value_id;
} else {
CARBON_DIAGNOSTIC(AliasRequiresNameRef, Error,
"alias initializer must be a name reference");
context.emitter().Emit(expr_node, AliasRequiresNameRef);
alias_type_id = SemIR::ErrorInst::SingletonTypeId;
alias_value_id = SemIR::ErrorInst::SingletonInstId;
}
auto alias_id = context.AddInst<SemIR::BindAlias>(
name_context.loc_id, {.type_id = alias_type_id,
.entity_name_id = entity_name_id,
.value_id = alias_value_id});
// Add the name of the binding to the current scope.
context.decl_name_stack().PopScope();
context.decl_name_stack().AddNameOrDiagnoseDuplicate(
name_context, alias_id, introducer.modifier_set.GetAccessKind());
return true;
}
} // namespace Carbon::Check