diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -73,7 +73,8 @@ number of arguments cause an assertion fault. - Fix multi-level pack expansion of undeclared function parameters. This fixes `Issue 56094 `_. - +- Fix `#57151 `_. + ``-Wcomma`` is emitted for void returning functions. Improvements to Clang's diagnostics ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp --- a/clang/lib/Sema/SemaExpr.cpp +++ b/clang/lib/Sema/SemaExpr.cpp @@ -13957,8 +13957,10 @@ return getLangOpts().CPlusPlus ? LHSType : LHSType.getAtomicUnqualifiedType(); } -// Only ignore explicit casts to void. -static bool IgnoreCommaOperand(const Expr *E) { +// Scenarios to ignore if expression E is: +// 1. an explicit cast expression into void +// 2. a function call expression that returns void +static bool IgnoreCommaOperand(const Expr *E, const ASTContext &Context) { E = E->IgnoreParens(); if (const CastExpr *CE = dyn_cast(E)) { @@ -13973,6 +13975,8 @@ } } + if (const auto *CE = dyn_cast(E)) + return CE->getCallReturnType(Context)->isVoidType(); return false; } @@ -14014,7 +14018,7 @@ } // Only allow some expressions on LHS to not warn. - if (IgnoreCommaOperand(LHS)) + if (IgnoreCommaOperand(LHS, Context)) return; Diag(Loc, diag::warn_comma_operator); diff --git a/clang/test/SemaCXX/warn-comma-operator.cpp b/clang/test/SemaCXX/warn-comma-operator.cpp --- a/clang/test/SemaCXX/warn-comma-operator.cpp +++ b/clang/test/SemaCXX/warn-comma-operator.cpp @@ -140,6 +140,27 @@ // CHECK: fix-it:{{.*}}:{[[@LINE-8]]:46-[[@LINE-8]]:46}:")" } + +void void_func(); +int int_func() { return 0; } + +void void_function_comma(){ + void_func(), int_func(); // expected no -Wcomma because of the returning type `void` + // Reported by https://github.com/llvm/llvm-project/issues/57151 + // Descriptions about -Wcomma: https://reviews.llvm.org/D3976 +} + +typedef void Void; +Void typedef_func(); + +void whatever() { + // We don't get confused about type aliases. + typedef_func(), int_func(); + // Even function pointers don't confuse us. + void (*fp)() = void_func; + fp(), int_func(); +} + #ifdef __cplusplus class S2 { public: @@ -296,4 +317,23 @@ (void)T{}, 0; static_cast(T{}), 0; } + +namespace { + +// issue #57151 + +struct S { + void mem() {} +}; + +void whatever() { + struct S s; + // Member function calls also work as expected. + s.mem(), int_func(); + // As do lambda calls. + []() { return; }(), int_func(); +} + +} // namespace + #endif // ifdef __cplusplus