clang-tools  3.8.0
UnusedAliasDeclsCheck.cpp
Go to the documentation of this file.
1 //===--- UnusedAliasDeclsCheck.cpp - clang-tidy----------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "UnusedAliasDeclsCheck.h"
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13 #include "clang/Lex/Lexer.h"
14 
15 using namespace clang::ast_matchers;
16 
17 namespace clang {
18 namespace tidy {
19 
20 void UnusedAliasDeclsCheck::registerMatchers(MatchFinder *Finder) {
21  // Only register the matchers for C++11; the functionality currently does not
22  // provide any benefit to other languages, despite being benign.
23  if (!getLangOpts().CPlusPlus11)
24  return;
25 
26  // We cannot do anything about headers (yet), as the alias declarations
27  // used in one header could be used by some other translation unit.
28  Finder->addMatcher(namespaceAliasDecl(isExpansionInMainFile()).bind("alias"),
29  this);
30  Finder->addMatcher(nestedNameSpecifier().bind("nns"), this);
31 }
32 
33 void UnusedAliasDeclsCheck::check(const MatchFinder::MatchResult &Result) {
34  if (const auto *AliasDecl = Result.Nodes.getNodeAs<NamedDecl>("alias")) {
35  FoundDecls[AliasDecl] = CharSourceRange::getCharRange(
36  AliasDecl->getLocStart(),
37  Lexer::findLocationAfterToken(
38  AliasDecl->getLocEnd(), tok::semi, *Result.SourceManager,
39  Result.Context->getLangOpts(),
40  /*SkipTrailingWhitespaceAndNewLine=*/true));
41  return;
42  }
43 
44  if (const auto *NestedName =
45  Result.Nodes.getNodeAs<NestedNameSpecifier>("nns")) {
46  if (const auto *AliasDecl = NestedName->getAsNamespaceAlias()) {
47  FoundDecls[AliasDecl] = CharSourceRange();
48  }
49  }
50 }
51 
52 void UnusedAliasDeclsCheck::onEndOfTranslationUnit() {
53  for (const auto &FoundDecl : FoundDecls) {
54  if (!FoundDecl.second.isValid())
55  continue;
56  diag(FoundDecl.first->getLocation(), "namespace alias decl '%0' is unused")
57  << FoundDecl.first->getName()
58  << FixItHint::CreateRemoval(FoundDecl.second);
59  }
60 }
61 
62 } // namespace tidy
63 } // namespace clang
std::unique_ptr< ast_matchers::MatchFinder > Finder
Definition: ClangTidy.cpp:188
const NamedDecl * Result
Definition: USRFinder.cpp:121