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mstr-six
f3b8e231ca
Malformed `base` declarations with an omitted colon need two different
recovery paths. For `extend base`, the consumed `extend` modifier
requires the parse tree to retain its `BaseColon` and base expression
children, so this synthesizes an errored `BaseColon` and continues
parsing the expression.
Other malformed forms, such as `base calss X {}`, now use the standard
declaration-error recovery: emit `ExpectedAfterBase`, skip past the
likely declaration end, and form an errored `BaseDecl` without inventing
a colon or cascading diagnostics.
The regression covers `extend base Foo;`, bare `base;`, and the reviewer
counterexample `base calss X {}`.
Tests:
- `prek run --files toolchain/parse/handle_base.cpp
toolchain/parse/testdata/class/fail_base.carbon`
- `./scripts/run_bazelisk.py test -c dbg //toolchain/parse/...`
- `./scripts/run_bazelisk.py test -c dbg //toolchain/testing:file_test`
AI assistance: OpenAI Codex helped inspect the parser recovery path,
implement the change, and run verification. The operator reviewed and
authorized the contribution.
Assisted-by: OpenAI Codex
48 lines
1.7 KiB
C++
48 lines
1.7 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/parse/context.h"
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#include "toolchain/parse/handle.h"
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namespace Carbon::Parse {
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// Handles a `base` declaration after the introducer.
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auto HandleBaseAfterIntroducer(Context& context) -> void {
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auto state = context.PopState();
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if (!context.ConsumeAndAddLeafNodeIf(Lex::TokenKind::Colon,
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NodeKind::BaseColon)) {
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CARBON_DIAGNOSTIC(ExpectedAfterBase, Error,
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"`class` or `:` expected after `base`");
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context.emitter().Emit(*context.position(), ExpectedAfterBase);
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auto base_token = *(context.position() - 1);
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auto previous_token = Lex::TokenIndex(base_token.index - 1);
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if (context.tokens().GetKind(previous_token) != Lex::TokenKind::Extend) {
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context.RecoverFromDeclError(state, NodeKind::BaseDecl,
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/*skip_past_likely_end=*/true);
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return;
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}
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// Preserve the `extend base` tree shape using an errored placeholder.
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context.AddLeafNode(NodeKind::BaseColon, *context.position(),
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/*has_error=*/true);
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state.has_error = true;
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}
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state.kind = StateKind::BaseDecl;
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context.PushState(state);
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context.PushState(StateKind::Expr);
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}
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// Handles processing of a complete `base: B` declaration.
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auto HandleBaseDecl(Context& context) -> void {
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auto state = context.PopState();
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context.AddNodeExpectingDeclSemi(state, NodeKind::BaseDecl,
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Lex::TokenKind::Base,
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/*is_def_allowed=*/false);
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}
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} // namespace Carbon::Parse
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