1//===--- UnusedAliasDeclsCheck.cpp - clang-tidy----------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "UnusedAliasDeclsCheck.h"
10#include "clang/AST/ASTContext.h"
11#include "clang/ASTMatchers/ASTMatchFinder.h"
12#include "clang/Lex/Lexer.h"
13
14using namespace clang::ast_matchers;
15
16namespace clang::tidy::misc {
17
18void UnusedAliasDeclsCheck::registerMatchers(MatchFinder *Finder) {
19 // We cannot do anything about headers (yet), as the alias declarations
20 // used in one header could be used by some other translation unit.
21 Finder->addMatcher(NodeMatch: namespaceAliasDecl(isExpansionInMainFile()).bind(ID: "alias"),
22 Action: this);
23 Finder->addMatcher(NodeMatch: nestedNameSpecifier().bind(ID: "nns"), Action: this);
24}
25
26void UnusedAliasDeclsCheck::check(const MatchFinder::MatchResult &Result) {
27 if (const auto *AliasDecl = Result.Nodes.getNodeAs<NamedDecl>(ID: "alias")) {
28 FoundDecls[AliasDecl] = CharSourceRange::getCharRange(
29 AliasDecl->getBeginLoc(),
30 Lexer::findLocationAfterToken(
31 loc: AliasDecl->getEndLoc(), TKind: tok::semi, SM: *Result.SourceManager,
32 LangOpts: getLangOpts(),
33 /*SkipTrailingWhitespaceAndNewLine=*/true));
34 return;
35 }
36
37 if (const auto *NestedName =
38 Result.Nodes.getNodeAs<NestedNameSpecifier>(ID: "nns")) {
39 if (const auto *AliasDecl = NestedName->getAsNamespaceAlias()) {
40 FoundDecls[AliasDecl] = CharSourceRange();
41 }
42 }
43}
44
45void UnusedAliasDeclsCheck::onEndOfTranslationUnit() {
46 for (const auto &FoundDecl : FoundDecls) {
47 if (!FoundDecl.second.isValid())
48 continue;
49 diag(FoundDecl.first->getLocation(), "namespace alias decl %0 is unused")
50 << FoundDecl.first << FixItHint::CreateRemoval(RemoveRange: FoundDecl.second);
51 }
52}
53
54} // namespace clang::tidy::misc
55

source code of clang-tools-extra/clang-tidy/misc/UnusedAliasDeclsCheck.cpp