diff --git a/clang-tools-extra/clang-tidy/readability/CMakeLists.txt b/clang-tools-extra/clang-tidy/readability/CMakeLists.txt index 0d0641c4b22bf..91e9354d454d2 100644 --- a/clang-tools-extra/clang-tidy/readability/CMakeLists.txt +++ b/clang-tools-extra/clang-tidy/readability/CMakeLists.txt @@ -49,6 +49,7 @@ add_clang_library(clangTidyReadabilityModule STATIC RedundantSmartptrGetCheck.cpp RedundantStringCStrCheck.cpp RedundantStringInitCheck.cpp + RedundantTypenameCheck.cpp ReferenceToConstructedTemporaryCheck.cpp SimplifyBooleanExprCheck.cpp SimplifySubscriptExprCheck.cpp diff --git a/clang-tools-extra/clang-tidy/readability/ReadabilityTidyModule.cpp b/clang-tools-extra/clang-tidy/readability/ReadabilityTidyModule.cpp index fcfac05b000e4..569302e6065f2 100644 --- a/clang-tools-extra/clang-tidy/readability/ReadabilityTidyModule.cpp +++ b/clang-tools-extra/clang-tidy/readability/ReadabilityTidyModule.cpp @@ -52,6 +52,7 @@ #include "RedundantSmartptrGetCheck.h" #include "RedundantStringCStrCheck.h" #include "RedundantStringInitCheck.h" +#include "RedundantTypenameCheck.h" #include "ReferenceToConstructedTemporaryCheck.h" #include "SimplifyBooleanExprCheck.h" #include "SimplifySubscriptExprCheck.h" @@ -143,6 +144,8 @@ class ReadabilityModule : public ClangTidyModule { "readability-redundant-parentheses"); CheckFactories.registerCheck( "readability-redundant-preprocessor"); + CheckFactories.registerCheck( + "readability-redundant-typename"); CheckFactories.registerCheck( "readability-reference-to-constructed-temporary"); CheckFactories.registerCheck( diff --git a/clang-tools-extra/clang-tidy/readability/RedundantTypenameCheck.cpp b/clang-tools-extra/clang-tidy/readability/RedundantTypenameCheck.cpp new file mode 100644 index 0000000000000..7da6c3decf90c --- /dev/null +++ b/clang-tools-extra/clang-tidy/readability/RedundantTypenameCheck.cpp @@ -0,0 +1,77 @@ +//===----------------------------------------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#include "RedundantTypenameCheck.h" +#include "clang/AST/TypeLoc.h" +#include "clang/ASTMatchers/ASTMatchFinder.h" +#include "clang/ASTMatchers/ASTMatchers.h" +#include "clang/Basic/Diagnostic.h" +#include "clang/Lex/Lexer.h" +#include "clang/Sema/DeclSpec.h" + +using namespace clang::ast_matchers; +using namespace clang::ast_matchers::internal; + +namespace clang::tidy::readability { + +void RedundantTypenameCheck::registerMatchers(MatchFinder *Finder) { + Finder->addMatcher(typedefTypeLoc().bind("typedefTypeLoc"), this); + + if (!getLangOpts().CPlusPlus20) + return; + + const auto InImplicitTypenameContext = anyOf( + hasParent(decl(anyOf( + typedefNameDecl(), templateTypeParmDecl(), nonTypeTemplateParmDecl(), + friendDecl(), fieldDecl(), + varDecl(hasDeclContext(anyOf(namespaceDecl(), translationUnitDecl())), + unless(parmVarDecl())), + parmVarDecl(hasParent(expr(requiresExpr()))), + parmVarDecl(hasParent(typeLoc(hasParent( + decl(anyOf(cxxMethodDecl(), hasParent(friendDecl()), + functionDecl(has(nestedNameSpecifier())))))))), + // Match return types. + functionDecl(unless(cxxConversionDecl()))))), + hasParent(expr(anyOf(cxxNamedCastExpr(), cxxNewExpr())))); + Finder->addMatcher(typeLoc(InImplicitTypenameContext).bind("typeloc"), this); +} + +void RedundantTypenameCheck::check(const MatchFinder::MatchResult &Result) { + const SourceLocation ElaboratedKeywordLoc = [&] { + if (const auto *TTL = + Result.Nodes.getNodeAs("typedefTypeLoc")) + return TTL->getElaboratedKeywordLoc(); + + TypeLoc InnermostTypeLoc = *Result.Nodes.getNodeAs("typeloc"); + while (const TypeLoc Next = InnermostTypeLoc.getNextTypeLoc()) + InnermostTypeLoc = Next; + + if (const auto DNTL = InnermostTypeLoc.getAs()) + return DNTL.getElaboratedKeywordLoc(); + + if (const auto TSTL = + InnermostTypeLoc.getAs()) + return TSTL.getElaboratedKeywordLoc(); + + return SourceLocation(); + }(); + + if (ElaboratedKeywordLoc.isInvalid()) + return; + + if (Token ElaboratedKeyword; + Lexer::getRawToken(ElaboratedKeywordLoc, ElaboratedKeyword, + *Result.SourceManager, getLangOpts()) || + ElaboratedKeyword.getRawIdentifier() != "typename") + return; + + diag(ElaboratedKeywordLoc, "redundant 'typename'") + << FixItHint::CreateRemoval(ElaboratedKeywordLoc); +} + +} // namespace clang::tidy::readability diff --git a/clang-tools-extra/clang-tidy/readability/RedundantTypenameCheck.h b/clang-tools-extra/clang-tidy/readability/RedundantTypenameCheck.h new file mode 100644 index 0000000000000..8e86b0c765fd7 --- /dev/null +++ b/clang-tools-extra/clang-tidy/readability/RedundantTypenameCheck.h @@ -0,0 +1,36 @@ +//===----------------------------------------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_REDUNDANTTYPENAMECHECK_H +#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_REDUNDANTTYPENAMECHECK_H + +#include "../ClangTidyCheck.h" + +namespace clang::tidy::readability { + +/// Finds redundant uses of the `typename` keyword. +/// +/// For the user-facing documentation see: +/// https://clang.llvm.org/extra/clang-tidy/checks/readability/redundant-typename.html +class RedundantTypenameCheck : public ClangTidyCheck { +public: + RedundantTypenameCheck(StringRef Name, ClangTidyContext *Context) + : ClangTidyCheck(Name, Context) {} + bool isLanguageVersionSupported(const LangOptions &LangOpts) const override { + return LangOpts.CPlusPlus; + } + void registerMatchers(ast_matchers::MatchFinder *Finder) override; + void check(const ast_matchers::MatchFinder::MatchResult &Result) override; + std::optional getCheckTraversalKind() const override { + return TK_IgnoreUnlessSpelledInSource; + } +}; + +} // namespace clang::tidy::readability + +#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_REDUNDANTTYPENAMECHECK_H diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst index 62e1987377989..52cf855ac9598 100644 --- a/clang-tools-extra/docs/ReleaseNotes.rst +++ b/clang-tools-extra/docs/ReleaseNotes.rst @@ -208,6 +208,11 @@ New checks Detect redundant parentheses. +- New :doc:`readability-redundant-typename + ` check. + + Finds redundant uses of the ``typename`` keyword. + New check aliases ^^^^^^^^^^^^^^^^^ diff --git a/clang-tools-extra/docs/clang-tidy/checks/list.rst b/clang-tools-extra/docs/clang-tidy/checks/list.rst index f94696d4ef9c7..c3f51757d72c2 100644 --- a/clang-tools-extra/docs/clang-tidy/checks/list.rst +++ b/clang-tools-extra/docs/clang-tidy/checks/list.rst @@ -409,6 +409,7 @@ Clang-Tidy Checks :doc:`readability-redundant-smartptr-get `, "Yes" :doc:`readability-redundant-string-cstr `, "Yes" :doc:`readability-redundant-string-init `, "Yes" + :doc:`readability-redundant-typename `, "Yes" :doc:`readability-reference-to-constructed-temporary `, :doc:`readability-simplify-boolean-expr `, "Yes" :doc:`readability-simplify-subscript-expr `, "Yes" diff --git a/clang-tools-extra/docs/clang-tidy/checks/readability/redundant-typename.rst b/clang-tools-extra/docs/clang-tidy/checks/readability/redundant-typename.rst new file mode 100644 index 0000000000000..7f5737f4e72b4 --- /dev/null +++ b/clang-tools-extra/docs/clang-tidy/checks/readability/redundant-typename.rst @@ -0,0 +1,26 @@ +.. title:: clang-tidy - readability-redundant-typename + +readability-redundant-typename +============================== + +Finds redundant uses of the ``typename`` keyword. + +``typename`` is redundant in two cases. First, before non-dependent names: + +.. code-block:: c++ + + /* typename */ std::vector::size_type size; + +And second, since C++20, before dependent names that appear in a context +where only a type is allowed (the following example shows just a few of them): + +.. code-block:: c++ + + template + using trait = /* typename */ T::type; + + template + struct S { + /* typename */ T::type variable; + /* typename */ T::type function(/* typename */ T::type); + }; diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-typename-cxx98.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-typename-cxx98.cpp new file mode 100644 index 0000000000000..74b0b49cdae8d --- /dev/null +++ b/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-typename-cxx98.cpp @@ -0,0 +1,19 @@ +// RUN: %check_clang_tidy -std=c++98,c++03 %s readability-redundant-typename %t \ +// RUN: -- -- -fno-delayed-template-parsing + +struct NotDependent { + typedef int R; +}; + +template +typename T::R f() { + static_cast(0); + + typename NotDependent::R NotDependentVar; + // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES: NotDependent::R NotDependentVar; + + void notDependentFunctionDeclaration(typename NotDependent::R); + // CHECK-MESSAGES: :[[@LINE-1]]:40: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES: void notDependentFunctionDeclaration(NotDependent::R); +} diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-typename.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-typename.cpp new file mode 100644 index 0000000000000..2ac0e034b88bb --- /dev/null +++ b/clang-tools-extra/test/clang-tidy/checkers/readability/redundant-typename.cpp @@ -0,0 +1,211 @@ +// RUN: %check_clang_tidy -std=c++11,c++14,c++17 %s readability-redundant-typename %t \ +// RUN: -- -- -fno-delayed-template-parsing +// RUN: %check_clang_tidy -std=c++20-or-later -check-suffixes=,20 %s readability-redundant-typename %t \ +// RUN: -- -- -fno-delayed-template-parsing + +struct NotDependent { + using R = int; +}; + +auto f(typename NotDependent::R) + // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES: auto f(NotDependent::R) + -> typename NotDependent::R + // CHECK-MESSAGES: :[[@LINE-1]]:6: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES: -> NotDependent::R +{ + return typename NotDependent::R(); + // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: redundant 'typename' [readability-redundant-typename] + // return NotDependent::R(); +} + +template < + typename T, + typename T::R V, + // CHECK-MESSAGES-20: :[[@LINE-1]]:3: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: T::R V, + typename U = typename T::R + // CHECK-MESSAGES-20: :[[@LINE-1]]:16: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: typename U = T::R +> +auto f() -> typename T::R +// CHECK-MESSAGES-20: :[[@LINE-1]]:13: warning: redundant 'typename' [readability-redundant-typename] +// CHECK-FIXES-20: auto f() -> T::R +{ + static_cast(0); + // CHECK-MESSAGES-20: :[[@LINE-1]]:15: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: static_cast(0); + + dynamic_cast(0); + // CHECK-MESSAGES-20: :[[@LINE-1]]:16: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: dynamic_cast(0); + + reinterpret_cast(0); + // CHECK-MESSAGES-20: :[[@LINE-1]]:20: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: reinterpret_cast(0); + + const_cast(0); + // CHECK-MESSAGES-20: :[[@LINE-1]]:14: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: const_cast(0); + + static_cast(0); + // CHECK-MESSAGES-20: :[[@LINE-1]]:15: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: static_cast(0); + + dynamic_cast(0); + // CHECK-MESSAGES-20: :[[@LINE-1]]:16: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: dynamic_cast(0); + + reinterpret_cast::R *>(0); + // CHECK-MESSAGES-20: :[[@LINE-1]]:26: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: reinterpret_cast::R *>(0); + + const_cast(0); + // CHECK-MESSAGES-20: :[[@LINE-1]]:20: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: const_cast(0); + + (typename T::R)(0); + + alignof(typename T::R); + + new typename T::R(); + // CHECK-MESSAGES-20: :[[@LINE-1]]:7: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: new T::R(); + + // CHECK-MESSAGES-20: :[[@LINE+2]]:15: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: static_cast(0); + + auto localFunctionDeclaration() -> typename T::R; + // CHECK-MESSAGES-20: :[[@LINE-1]]:38: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: auto localFunctionDeclaration() -> T::R; + + void (*PointerToFunction)(typename T::R); + void anotherLocalFunctionDeclaration(typename T::R); + + typename T::R DependentVar; + typename NotDependent::R NotDependentVar; + // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES: NotDependent::R NotDependentVar; + + return typename T::R(); +} + +template +using trait = const typename T::R ****; +// CHECK-MESSAGES-20: :[[@LINE-1]]:21: warning: redundant 'typename' [readability-redundant-typename] +// CHECK-FIXES-20: using trait = const T::R ****; + +template +using t = typename T::template R; +// CHECK-MESSAGES-20: :[[@LINE-1]]:11: warning: redundant 'typename' [readability-redundant-typename] +// CHECK-FIXES-20: using t = T::template R; + +template +trait m(); + +#if __cplusplus >= 202002L + +template +concept c = requires(typename T::R) { +// CHECK-MESSAGES-20: :[[@LINE-1]]:22: warning: redundant 'typename' [readability-redundant-typename] +// CHECK-FIXES-20: concept c = requires(T::R) { + typename T::R; +}; + +template +requires c +void b(); + +#endif // __cplusplus >= 202002L + +template +struct PartiallySpecializedType {}; + +template +struct PartiallySpecializedType {}; + +#if __cplusplus >= 201402L + +template +typename T::R v = typename T::R(); +// CHECK-MESSAGES-20: :[[@LINE-1]]:1: warning: redundant 'typename' [readability-redundant-typename] +// CHECK-FIXES-20: T::R v = typename T::R(); + +#endif // __cplusplus >= 201402L + +template +typename T::R f(); +// CHECK-MESSAGES-20: :[[@LINE-1]]:1: warning: redundant 'typename' [readability-redundant-typename] +// CHECK-FIXES-20: T::R f(); + +template +void n(typename T::R); + +namespace ns { + +template +void f(typename T::R1, typename T::R2); + +} // namespace ns + +template +void ns::f( + typename T::R1, + // CHECK-MESSAGES-20: :[[@LINE-1]]:3: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: T::R1, + typename T::R2 + // CHECK-MESSAGES-20: :[[@LINE-1]]:3: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: T::R2 +); + +template +void p(typename Ts::R...); + +template +class A { +public: + friend typename T::R; + // CHECK-MESSAGES-20: :[[@LINE-1]]:10: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: friend T::R; + + typedef typename T::R a; + // CHECK-MESSAGES-20: :[[@LINE-1]]:11: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: typedef T::R a; + + const typename T::R typedef b; + // CHECK-MESSAGES-20: :[[@LINE-1]]:9: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: const T::R typedef b; + + typename T::R v; + // CHECK-MESSAGES-20: :[[@LINE-1]]:3: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: T::R v; + + typename T::R + // CHECK-MESSAGES-20: :[[@LINE-1]]:3: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: T::R + g(typename T::R) {} + // CHECK-MESSAGES-20: :[[@LINE-1]]:5: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: g(T::R) {} + + void h(typename T::R = typename T::R()) {} + // CHECK-MESSAGES-20: :[[@LINE-1]]:10: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: void h(T::R = typename T::R()) {} + + void p(typename Ts::R...); + // CHECK-MESSAGES-20: :[[@LINE-1]]:10: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: void p(Ts::R...); + + friend void k(typename T::R) {} + // CHECK-MESSAGES-20: :[[@LINE-1]]:17: warning: redundant 'typename' [readability-redundant-typename] + // CHECK-FIXES-20: friend void k(T::R) {} + + friend struct T::R; + using typename T::R; + enum E1 : typename T::R {}; + enum class E2 : typename T::R {}; + operator typename T::R(); + void m() { this->operator typename T::R(); } +}; diff --git a/clang/include/clang/ASTMatchers/ASTMatchers.h b/clang/include/clang/ASTMatchers/ASTMatchers.h index 492863ddfc4a1..9e833bf2f96a2 100644 --- a/clang/include/clang/ASTMatchers/ASTMatchers.h +++ b/clang/include/clang/ASTMatchers/ASTMatchers.h @@ -2763,6 +2763,20 @@ extern const internal::VariadicDynCastAllOfMatcher extern const internal::VariadicDynCastAllOfMatcher cxxConstCastExpr; +/// Matches any named cast expression. +/// +/// Example: Matches all four of the casts in +/// \code +/// struct S { virtual void f(); }; +/// S* p = nullptr; +/// S* ptr1 = static_cast(p); +/// S* ptr2 = reinterpret_cast(p); +/// S* ptr3 = dynamic_cast(p); +/// S* ptr4 = const_cast(p); +/// \endcode +extern const internal::VariadicDynCastAllOfMatcher + cxxNamedCastExpr; + /// Matches a C-style cast expression. /// /// Example: Matches (int) 2.2f in @@ -6987,6 +7001,20 @@ extern const internal::VariadicDynCastAllOfMatcher< TypeLoc, TemplateSpecializationTypeLoc> templateSpecializationTypeLoc; +/// Matches `TypedefTypeLoc`s. +/// +/// Given +/// \code +/// using t1 = int; +/// template struct S { using t2 = int; }; +/// t1 var1; +/// const S::t2* var2; +/// \endcode +/// typedefTypeLoc() +/// matches `t1` (in the declaration of var1) and `S::t2`. +extern const internal::VariadicDynCastAllOfMatcher + typedefTypeLoc; + /// Matches template specialization `TypeLoc`s, class template specializations, /// variable template specializations, and function template specializations /// that have at least one `TemplateArgumentLoc` matching the given diff --git a/clang/lib/ASTMatchers/ASTMatchersInternal.cpp b/clang/lib/ASTMatchers/ASTMatchersInternal.cpp index 1f0e007dafc65..516882232cdf5 100644 --- a/clang/lib/ASTMatchers/ASTMatchersInternal.cpp +++ b/clang/lib/ASTMatchers/ASTMatchersInternal.cpp @@ -810,6 +810,8 @@ const internal::VariadicDynCastAllOfMatcher const internal::VariadicDynCastAllOfMatcher templateSpecializationTypeLoc; +const internal::VariadicDynCastAllOfMatcher + typedefTypeLoc; const internal::VariadicDynCastAllOfMatcher unaryExprOrTypeTraitExpr; @@ -1009,6 +1011,8 @@ const internal::VariadicDynCastAllOfMatcher cxxDynamicCastExpr; const internal::VariadicDynCastAllOfMatcher cxxConstCastExpr; +const internal::VariadicDynCastAllOfMatcher + cxxNamedCastExpr; const internal::VariadicDynCastAllOfMatcher cStyleCastExpr; const internal::VariadicDynCastAllOfMatcher