1 //===--- UnusedUsingDeclsCheck.h - clang-tidy--------------------*- C++ -*-===// 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 #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_UNUSED_USING_DECLS_H 10 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_UNUSED_USING_DECLS_H 11 12 #include "../ClangTidyCheck.h" 13 #include "../utils/FileExtensionsUtils.h" 14 #include "llvm/ADT/SmallPtrSet.h" 15 #include <vector> 16 17 namespace clang::tidy::misc { 18 19 /// Finds unused using declarations. 20 /// 21 /// For the user-facing documentation see: 22 /// http://clang.llvm.org/extra/clang-tidy/checks/misc/unused-using-decls.html 23 class UnusedUsingDeclsCheck : public ClangTidyCheck { 24 public: 25 UnusedUsingDeclsCheck(StringRef Name, ClangTidyContext *Context); 26 void registerMatchers(ast_matchers::MatchFinder *Finder) override; 27 void check(const ast_matchers::MatchFinder::MatchResult &Result) override; 28 void onEndOfTranslationUnit() override; 29 30 private: 31 void removeFromFoundDecls(const Decl *D); 32 33 struct UsingDeclContext { UsingDeclContextUsingDeclContext34 explicit UsingDeclContext(const UsingDecl *FoundUsingDecl) 35 : FoundUsingDecl(FoundUsingDecl) {} 36 // A set saves all UsingShadowDecls introduced by a UsingDecl. A UsingDecl 37 // can introduce multiple UsingShadowDecls in some cases (such as 38 // overloaded functions). 39 llvm::SmallPtrSet<const Decl *, 4> UsingTargetDecls; 40 // The original UsingDecl. 41 const UsingDecl *FoundUsingDecl; 42 // The source range of the UsingDecl. 43 CharSourceRange UsingDeclRange; 44 // Whether the UsingDecl is used. 45 bool IsUsed = false; 46 }; 47 48 std::vector<UsingDeclContext> Contexts; 49 50 StringRef RawStringHeaderFileExtensions; 51 FileExtensionsSet HeaderFileExtensions; 52 }; 53 54 } // namespace clang::tidy::misc 55 56 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_UNUSED_USING_DECLS_H 57