llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang-tidy Author: Danny Mösch (SimplyDanny) <details> <summary>Changes</summary> Closes #<!-- -->75788. The idea is to check each return statements for an expression that has type `void` as this is only possible in a function with `void` return type. The implementation seems too simple. I might have missed something. --- Full diff: https://github.com/llvm/llvm-project/pull/76249.diff 8 Files Affected: - (modified) clang-tools-extra/clang-tidy/readability/CMakeLists.txt (+1) - (modified) clang-tools-extra/clang-tidy/readability/ReadabilityTidyModule.cpp (+3) - (added) clang-tools-extra/clang-tidy/readability/ReturnExpressionInVoidFunctionCheck.cpp (+27) - (added) clang-tools-extra/clang-tidy/readability/ReturnExpressionInVoidFunctionCheck.h (+30) - (modified) clang-tools-extra/docs/ReleaseNotes.rst (+7) - (modified) clang-tools-extra/docs/clang-tidy/checks/list.rst (+1) - (added) clang-tools-extra/docs/clang-tidy/checks/readability/return-expression-in-void-function.rst (+30) - (added) clang-tools-extra/test/clang-tidy/checkers/readability/return-expression-in-void-function.cpp (+23) ``````````diff diff --git a/clang-tools-extra/clang-tidy/readability/CMakeLists.txt b/clang-tools-extra/clang-tidy/readability/CMakeLists.txt index 5452c2d48a4617..7d0399ed901267 100644 --- a/clang-tools-extra/clang-tidy/readability/CMakeLists.txt +++ b/clang-tools-extra/clang-tidy/readability/CMakeLists.txt @@ -42,6 +42,7 @@ add_clang_library(clangTidyReadabilityModule RedundantStringCStrCheck.cpp RedundantStringInitCheck.cpp ReferenceToConstructedTemporaryCheck.cpp + ReturnExpressionInVoidFunctionCheck.cpp SimplifyBooleanExprCheck.cpp SimplifySubscriptExprCheck.cpp StaticAccessedThroughInstanceCheck.cpp diff --git a/clang-tools-extra/clang-tidy/readability/ReadabilityTidyModule.cpp b/clang-tools-extra/clang-tidy/readability/ReadabilityTidyModule.cpp index b8e6e641432060..2a9134071b9a72 100644 --- a/clang-tools-extra/clang-tidy/readability/ReadabilityTidyModule.cpp +++ b/clang-tools-extra/clang-tidy/readability/ReadabilityTidyModule.cpp @@ -45,6 +45,7 @@ #include "RedundantStringCStrCheck.h" #include "RedundantStringInitCheck.h" #include "ReferenceToConstructedTemporaryCheck.h" +#include "ReturnExpressionInVoidFunctionCheck.h" #include "SimplifyBooleanExprCheck.h" #include "SimplifySubscriptExprCheck.h" #include "StaticAccessedThroughInstanceCheck.h" @@ -119,6 +120,8 @@ class ReadabilityModule : public ClangTidyModule { "readability-redundant-preprocessor"); CheckFactories.registerCheck<ReferenceToConstructedTemporaryCheck>( "readability-reference-to-constructed-temporary"); + CheckFactories.registerCheck<ReturnExpressionInVoidFunctionCheck>( + "readability-return-expression-in-void-function"); CheckFactories.registerCheck<SimplifySubscriptExprCheck>( "readability-simplify-subscript-expr"); CheckFactories.registerCheck<StaticAccessedThroughInstanceCheck>( diff --git a/clang-tools-extra/clang-tidy/readability/ReturnExpressionInVoidFunctionCheck.cpp b/clang-tools-extra/clang-tidy/readability/ReturnExpressionInVoidFunctionCheck.cpp new file mode 100644 index 00000000000000..fb6073b60b27f5 --- /dev/null +++ b/clang-tools-extra/clang-tidy/readability/ReturnExpressionInVoidFunctionCheck.cpp @@ -0,0 +1,27 @@ +//===--- ReturnExpressionInVoidFunctionCheck.cpp - clang-tidy -------------===// +// +// 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 "ReturnExpressionInVoidFunctionCheck.h" +#include "clang/AST/Stmt.h" +#include "clang/ASTMatchers/ASTMatchFinder.h" +#include "clang/ASTMatchers/ASTMatchers.h" + +using namespace clang::ast_matchers; + +namespace clang::tidy::readability { + +void ReturnExpressionInVoidFunctionCheck::registerMatchers(MatchFinder *Finder) { + Finder->addMatcher(returnStmt(hasReturnValue(hasType(voidType()))).bind("void_return"), this); +} + +void ReturnExpressionInVoidFunctionCheck::check(const MatchFinder::MatchResult &Result) { + const auto *VoidReturn = Result.Nodes.getNodeAs<ReturnStmt>("void_return"); + diag(VoidReturn->getBeginLoc(), "return statements should not return void"); +} + +} // namespace clang::tidy::readability diff --git a/clang-tools-extra/clang-tidy/readability/ReturnExpressionInVoidFunctionCheck.h b/clang-tools-extra/clang-tidy/readability/ReturnExpressionInVoidFunctionCheck.h new file mode 100644 index 00000000000000..e28f9cebd2620e --- /dev/null +++ b/clang-tools-extra/clang-tidy/readability/ReturnExpressionInVoidFunctionCheck.h @@ -0,0 +1,30 @@ +//===--- ReturnExpressionInVoidFunctionCheck.h - clang-tidy -----*- C++ -*-===// +// +// 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_RETURNEXPRESSIONINVOIDFUNCTIONCHECK_H +#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_RETURNEXPRESSIONINVOIDFUNCTIONCHECK_H + +#include "../ClangTidyCheck.h" + +namespace clang::tidy::readability { + +/// Looks for statements returning expressions of type `void`. +/// +/// For the user-facing documentation see: +/// http://clang.llvm.org/extra/clang-tidy/checks/readability/return-expression-in-void-function.html +class ReturnExpressionInVoidFunctionCheck : public ClangTidyCheck { +public: + ReturnExpressionInVoidFunctionCheck(StringRef Name, ClangTidyContext *Context) + : ClangTidyCheck(Name, Context) {} + void registerMatchers(ast_matchers::MatchFinder *Finder) override; + void check(const ast_matchers::MatchFinder::MatchResult &Result) override; +}; + +} // namespace clang::tidy::readability + +#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_RETURNEXPRESSIONINVOIDFUNCTIONCHECK_H diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst index 6d91748e4cef18..20896df0d340aa 100644 --- a/clang-tools-extra/docs/ReleaseNotes.rst +++ b/clang-tools-extra/docs/ReleaseNotes.rst @@ -218,6 +218,13 @@ New checks Detects C++ code where a reference variable is used to extend the lifetime of a temporary object that has just been constructed. +- New :doc:`readability-return-expression-in-void-function + <clang-tidy/checks/readability/return-expression-in-void-function>` check. + + Complains about statements returning expressions of type ``void``. It can be + confusing if a function returns an expression even though its return type is + ``void``. + 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 31f0e090db1d7d..f1282b4a6b766e 100644 --- a/clang-tools-extra/docs/clang-tidy/checks/list.rst +++ b/clang-tools-extra/docs/clang-tidy/checks/list.rst @@ -371,6 +371,7 @@ Clang-Tidy Checks :doc:`readability-redundant-string-cstr <readability/redundant-string-cstr>`, "Yes" :doc:`readability-redundant-string-init <readability/redundant-string-init>`, "Yes" :doc:`readability-reference-to-constructed-temporary <readability/reference-to-constructed-temporary>`, + :doc:`readability-return-expression-in-void-function <readability/return-expression-in-void-function>`, "Yes" :doc:`readability-simplify-boolean-expr <readability/simplify-boolean-expr>`, "Yes" :doc:`readability-simplify-subscript-expr <readability/simplify-subscript-expr>`, "Yes" :doc:`readability-static-accessed-through-instance <readability/static-accessed-through-instance>`, "Yes" diff --git a/clang-tools-extra/docs/clang-tidy/checks/readability/return-expression-in-void-function.rst b/clang-tools-extra/docs/clang-tidy/checks/readability/return-expression-in-void-function.rst new file mode 100644 index 00000000000000..dd07b95550e6f8 --- /dev/null +++ b/clang-tools-extra/docs/clang-tidy/checks/readability/return-expression-in-void-function.rst @@ -0,0 +1,30 @@ +.. title:: clang-tidy - readability-return-expression-in-void-function + +readability-return-expression-in-void-function +============================================== + +Complains about statements returning expressions of type ``void``. It can be +confusing if a function returns an expression even though its return type is +``void``. + +Example: + +.. code-block:: + + void g(); + void f() { + // ... + return g(); + } + +In a long function body, the ``return`` statements suggests that the function +returns a value. However, ``return g();`` is combination of two statements that +should be written as + +.. code-block:: + + g(); + return; + +to make clear that ``g()`` is called and immediately afterwards the function +returns (nothing). diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/return-expression-in-void-function.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/return-expression-in-void-function.cpp new file mode 100644 index 00000000000000..05e2f454abcd35 --- /dev/null +++ b/clang-tools-extra/test/clang-tidy/checkers/readability/return-expression-in-void-function.cpp @@ -0,0 +1,23 @@ +// RUN: %check_clang_tidy %s readability-return-expression-in-void-function %t + +void f1(); + +void f2() { + return f1(); + // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: return statements should not return void [readability-return-expression-in-void-function] +} + +void f3(bool b) { + if (b) return f1(); + // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: return statements should not return void [readability-return-expression-in-void-function] + return f2(); + // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: return statements should not return void [readability-return-expression-in-void-function] +} + +template<class T> +T f4() {} + +void f5() { + return f4<void>(); + // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: return statements should not return void [readability-return-expression-in-void-function] +} `````````` </details> https://github.com/llvm/llvm-project/pull/76249 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
