xref: /llvm-project/clang-tools-extra/clang-tidy/bugprone/ForwardDeclarationNamespaceCheck.h (revision 4718da506091a37ca4863d979bc541e359b79b10)
1 //===--- ForwardDeclarationNamespaceCheck.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_BUGPRONE_FORWARDDECLARATIONNAMESPACECHECK_H
10 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_FORWARDDECLARATIONNAMESPACECHECK_H
11 
12 #include "../ClangTidyCheck.h"
13 #include "llvm/ADT/SmallPtrSet.h"
14 #include <set>
15 #include <vector>
16 
17 namespace clang::tidy::bugprone {
18 
19 /// Checks if an unused forward declaration is in a wrong namespace.
20 ///
21 /// The check inspects all unused forward declarations and checks if there is
22 /// any declaration/definition with the same name, which could indicate
23 /// that the forward declaration is potentially in a wrong namespace.
24 ///
25 /// \code
26 ///   namespace na { struct A; }
27 ///   namespace nb { struct A {} };
28 ///   nb::A a;
29 ///   // warning : no definition found for 'A', but a definition with the same
30 ///   name 'A' found in another namespace 'nb::'
31 /// \endcode
32 ///
33 /// This check can only generate warnings, but it can't suggest fixes at this
34 /// point.
35 ///
36 /// For the user-facing documentation see:
37 /// http://clang.llvm.org/extra/clang-tidy/checks/bugprone/forward-declaration-namespace.html
38 class ForwardDeclarationNamespaceCheck : public ClangTidyCheck {
39 public:
ForwardDeclarationNamespaceCheck(StringRef Name,ClangTidyContext * Context)40   ForwardDeclarationNamespaceCheck(StringRef Name, ClangTidyContext *Context)
41       : ClangTidyCheck(Name, Context) {}
42   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
43   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
44   void onEndOfTranslationUnit() override;
45 
46 private:
47   llvm::StringMap<std::vector<const CXXRecordDecl *>> DeclNameToDefinitions;
48   llvm::StringMap<std::vector<const CXXRecordDecl *>> DeclNameToDeclarations;
49   llvm::SmallPtrSet<const Type *, 16> FriendTypes;
50 };
51 
52 } // namespace clang::tidy::bugprone
53 
54 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_FORWARDDECLARATIONNAMESPACECHECK_H
55