1 //===--- UsingNamespaceDirectiveCheck.cpp - clang-tidy ----------*- C++ -*-===// 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 "UsingNamespaceDirectiveCheck.h" 11 #include "clang/AST/ASTContext.h" 12 #include "clang/ASTMatchers/ASTMatchFinder.h" 13 #include "clang/ASTMatchers/ASTMatchers.h" 14 15 using namespace clang::ast_matchers; 16 17 namespace clang { 18 namespace tidy { 19 namespace google { 20 namespace build { 21 22 void UsingNamespaceDirectiveCheck::registerMatchers( 23 ast_matchers::MatchFinder *Finder) { 24 // Only register the matchers for C++; the functionality currently does not 25 // provide any benefit to other languages, despite being benign. 26 if (getLangOpts().CPlusPlus) 27 Finder->addMatcher(usingDirectiveDecl().bind("usingNamespace"), this); 28 } 29 30 void UsingNamespaceDirectiveCheck::check( 31 const MatchFinder::MatchResult &Result) { 32 const auto *U = Result.Nodes.getNodeAs<UsingDirectiveDecl>("usingNamespace"); 33 SourceLocation Loc = U->getLocStart(); 34 if (U->isImplicit() || !Loc.isValid()) 35 return; 36 37 // Do not warn if namespace is a std namespace with user-defined literals. The 38 // user-defined literals can only be used with a using directive. 39 if (isStdLiteralsNamespace(U->getNominatedNamespace())) 40 return; 41 42 diag(Loc, "do not use namespace using-directives; " 43 "use using-declarations instead"); 44 // TODO: We could suggest a list of using directives replacing the using 45 // namespace directive. 46 } 47 48 bool UsingNamespaceDirectiveCheck::isStdLiteralsNamespace( 49 const NamespaceDecl *NS) { 50 if (!NS->getName().endswith("literals")) 51 return false; 52 53 const auto *Parent = dyn_cast_or_null<NamespaceDecl>(NS->getParent()); 54 if (!Parent) 55 return false; 56 57 if (Parent->isStdNamespace()) 58 return true; 59 60 return Parent->getName() == "literals" && Parent->getParent() && 61 Parent->getParent()->isStdNamespace(); 62 } 63 } // namespace build 64 } // namespace google 65 } // namespace tidy 66 } // namespace clang 67