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| //===--- UnusedAliasDeclsCheck.cpp - clang-tidy----------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "UnusedAliasDeclsCheck.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/Lex/Lexer.h"
using namespace clang::ast_matchers;
namespace clang {
namespace tidy {
namespace misc {
void UnusedAliasDeclsCheck::registerMatchers(MatchFinder *Finder) {
// Only register the matchers for C++11; the functionality currently does not
// provide any benefit to other languages, despite being benign.
if (!getLangOpts().CPlusPlus11)
return;
// We cannot do anything about headers (yet), as the alias declarations
// used in one header could be used by some other translation unit.
Finder->addMatcher(namespaceAliasDecl(isExpansionInMainFile()).bind("alias"),
this);
Finder->addMatcher(nestedNameSpecifier().bind("nns"), this);
}
void UnusedAliasDeclsCheck::check(const MatchFinder::MatchResult &Result) {
if (const auto *AliasDecl = Result.Nodes.getNodeAs<NamedDecl>("alias")) {
FoundDecls[AliasDecl] = CharSourceRange::getCharRange(
AliasDecl->getBeginLoc(),
Lexer::findLocationAfterToken(
AliasDecl->getEndLoc(), tok::semi, *Result.SourceManager,
getLangOpts(),
/*SkipTrailingWhitespaceAndNewLine=*/true));
return;
}
if (const auto *NestedName =
Result.Nodes.getNodeAs<NestedNameSpecifier>("nns")) {
if (const auto *AliasDecl = NestedName->getAsNamespaceAlias()) {
FoundDecls[AliasDecl] = CharSourceRange();
}
}
}
void UnusedAliasDeclsCheck::onEndOfTranslationUnit() {
for (const auto &FoundDecl : FoundDecls) {
if (!FoundDecl.second.isValid())
continue;
diag(FoundDecl.first->getLocation(), "namespace alias decl %0 is unused")
<< FoundDecl.first << FixItHint::CreateRemoval(FoundDecl.second);
}
}
} // namespace misc
} // namespace tidy
} // namespace clang
|