Files
carbon-lang/toolchain/check/handle_match_first.cpp
T
Dana Jansens d46b040290 Connect impls to their containing match_first block (#7486)
When we check an `impl` decl, find the containing `match_first` block,
if any, and store a connection to it in the `SemIR::Impl` structure,
along with the impl's position in that `match_first` block so that we
can sort/prioritize the `SemIR::Impl`s later.

Also, update the `is_final` flag if the `match_first` block is modified
as `final`. But ensure we diagnose trying to put a `final impl`, or a
redeclaration of one, in a `match_first` block. Also diagnose if an impl
is attached to a `match_first` block more than once - either in two
different blocks or in the same block at different positions.

Putting the `match_first` connection on the `SemIR::Impl` structure
means we have to import it, so implement import and add a smoke test for
that, which ensures nothing explodes.

Drop the `scope_stack` entry for the `match_first` block, as it was not
needed. Once we started tracking the `match_first` size on the `Context`
class, it became more straightforward to just store the `match_first`
decl `InstId` in the same place. The `match_first` block is not supposed
to act like a different scope for the purpose of redecls anyhow, so it's
a bit simpler this way.
2026-07-13 19:14:38 +00:00

67 lines
2.5 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/convert.h"
#include "toolchain/check/handle.h"
#include "toolchain/check/keyword_modifier_set.h"
#include "toolchain/check/modifiers.h"
#include "toolchain/diagnostics/diagnostic.h"
namespace Carbon::Check {
auto HandleParseNode(Context& context,
Parse::MatchFirstIntroducerId /*node_id*/) -> bool {
// Optional modifiers follow.
context.decl_introducer_state_stack().Push<Lex::TokenKind::MatchFirst>();
return true;
}
auto HandleParseNode(Context& context,
Parse::MatchFirstDefinitionStartId node_id) -> bool {
auto enclosing_scope_inst_id = context.scope_stack().PeekInstId();
if (context.match_first_context() ||
!context.insts()
.IsOneOf<SemIR::ClassDecl, SemIR::FunctionDecl, SemIR::Namespace>(
enclosing_scope_inst_id)) {
CARBON_DIAGNOSTIC(
MatchFirstInWrongScope, Error,
"found `match_first` in invalid scope; expected namespace or class");
auto builder = context.emitter().Build(node_id, MatchFirstInWrongScope);
CARBON_DIAGNOSTIC(MatchFirstInWrongScopeNote, Note,
"in enclosing scope here");
builder.Note(enclosing_scope_inst_id, MatchFirstInWrongScopeNote);
builder.Emit();
context.node_stack().Push(node_id, SemIR::ErrorInst::InstId);
return true;
}
const auto& introducer = context.decl_introducer_state_stack().innermost();
bool is_final = introducer.modifier_set.HasAnyOf(KeywordModifierSet::Final);
auto decl_id = AddInst<SemIR::MatchFirstDecl>(
context, node_id, {.enclosing_scope_inst_id = enclosing_scope_inst_id});
context.match_first_context() = {.decl_id = decl_id, .is_final = is_final};
context.node_stack().Push(node_id, decl_id);
return true;
}
auto HandleParseNode(Context& context, Parse::MatchFirstId /*node_id*/)
-> bool {
auto decl_id =
context.node_stack().Pop<Parse::NodeKind::MatchFirstDefinitionStart>();
if (decl_id != SemIR::ErrorInst::InstId) {
context.match_first_context() = std::nullopt;
}
auto introducer =
context.decl_introducer_state_stack().Pop<Lex::TokenKind::MatchFirst>();
// Diagnose modifiers that are not allowed.
LimitModifiersOnDecl(context, introducer, KeywordModifierSet::MatchFirst);
return true;
}
} // namespace Carbon::Check