1 //===--- MoveForwardingReferenceCheck.h - 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 #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_MOVEFORWARDINGREFERENCECHECK_H 10 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_MOVEFORWARDINGREFERENCECHECK_H 11 12 #include "../ClangTidyCheck.h" 13 14 namespace clang { 15 namespace tidy { 16 namespace bugprone { 17 18 /// The check warns if std::move is applied to a forwarding reference (i.e. an 19 /// rvalue reference of a function template argument type). 20 /// 21 /// If a developer is unaware of the special rules for template argument 22 /// deduction on forwarding references, it will seem reasonable to apply 23 /// std::move to the forwarding reference, in the same way that this would be 24 /// done for a "normal" rvalue reference. 25 /// 26 /// This has a consequence that is usually unwanted and possibly surprising: if 27 /// the function that takes the forwarding reference as its parameter is called 28 /// with an lvalue, that lvalue will be moved from (and hence placed into an 29 /// indeterminate state) even though no std::move was applied to the lvalue at 30 /// the call site. 31 // 32 /// The check suggests replacing the std::move with a std::forward. 33 /// 34 /// For the user-facing documentation see: 35 /// http://clang.llvm.org/extra/clang-tidy/checks/bugprone-move-forwarding-reference.html 36 class MoveForwardingReferenceCheck : public ClangTidyCheck { 37 public: MoveForwardingReferenceCheck(StringRef Name,ClangTidyContext * Context)38 MoveForwardingReferenceCheck(StringRef Name, ClangTidyContext *Context) 39 : ClangTidyCheck(Name, Context) {} isLanguageVersionSupported(const LangOptions & LangOpts)40 bool isLanguageVersionSupported(const LangOptions &LangOpts) const override { 41 return LangOpts.CPlusPlus11; 42 } 43 void registerMatchers(ast_matchers::MatchFinder *Finder) override; 44 void check(const ast_matchers::MatchFinder::MatchResult &Result) override; 45 }; 46 47 } // namespace bugprone 48 } // namespace tidy 49 } // namespace clang 50 51 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_MOVEFORWARDINGREFERENCECHECK_H 52