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https://github.com/carbon-language/carbon-lang.git
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Jon Ross-Perkins
34651f429f
Fixes ordering (using DIAGNOSTIC_ON_SCOPE). Removes an obsolete TODO to add an error that's adjacent to the indicated error. Also moves the file to patterns: it was the only file in `dataflow`, and patterns also contains the related underscore binding tests. Assisted-by: Google Antigravity with Gemini 3 Flash
55 lines
1.9 KiB
C++
55 lines
1.9 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/unused.h"
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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/diagnostic_helpers.h"
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namespace Carbon::Check {
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auto CheckUnusedBinding(Context& context, SemIR::NameId name_id,
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const LexicalLookup::Result& result) -> void {
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// Don't warn about the special name `_`. Other special names, such as `self`,
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// are warned if unused. `.Self` is also excluded as it is often implicit.
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if (name_id == SemIR::NameId::Underscore ||
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name_id == SemIR::NameId::PeriodSelf) {
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return;
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}
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// Don't warn about names that aren't in the current file.
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auto decl_loc = context.insts().GetCanonicalLocId(result.inst_id);
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if (decl_loc.kind() == SemIR::LocId::Kind::ImportIRInstId) {
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return;
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}
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auto binding = context.insts().TryGetAs<SemIR::AnyBinding>(result.inst_id);
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if (!binding) {
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return;
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}
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const auto& entity_name = context.entity_names().Get(binding->entity_name_id);
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if (entity_name.is_unused) {
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if (result.use_loc_id.has_value()) {
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CARBON_DIAGNOSTIC_ON_SCOPE(UnusedButUsed, Error,
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"variable `{0}` marked `unused` but used",
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SemIR::NameId);
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CARBON_DIAGNOSTIC(UnusedButUsedHere, Note, "usage here");
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context.emitter()
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.Build(decl_loc, UnusedButUsed, name_id)
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.Note(result.use_loc_id, UnusedButUsedHere)
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.Emit();
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}
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} else {
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if (!result.use_loc_id.has_value() && result.is_decl_reachable) {
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CARBON_DIAGNOSTIC_ON_SCOPE(UnusedBinding, Warning, "binding `{0}` unused",
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SemIR::NameId);
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context.emitter().Emit(decl_loc, UnusedBinding, name_id);
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}
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}
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}
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} // namespace Carbon::Check
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