Files
carbon-lang/toolchain/check/handle_alias.cpp
T
Richard Smith 6dda094928 Superficial support for template modifier on symbolic bindings. (#4948)
Change parse tree from `template (T:! type)` to `(template T):! type`,
so that we have information about whether a binding is a template
binding available when forming the representation of the binding
pattern. This incidentally fixes a bug that we would accept `template
addr A:! B` instead of the intended `addr template A:! B`.

Track whether a symbolic binding is a template binding on the
`EntityName` object. I'm borrowing a bit from the `CompileTimeBindIndex`
for this in order to avoid making `EntityName`s larger. Longer-term, we
should think about using a different representation for symbolic
bindings, to avoid including these fields in all `EntityName`s, but
that's out of scope for this change.

So far, template bindings are treated as having the same phase as
checked bindings, but that will change in a future PR.
2025-02-13 02:15:22 +00:00

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2.9 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
#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();
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});
auto alias_type_id = SemIR::TypeId::None;
auto alias_value_id = SemIR::InstId::None;
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().AddNameOrDiagnose(
name_context, alias_id, introducer.modifier_set.GetAccessKind());
return true;
}
} // namespace Carbon::Check