[PATCH] D131892: [Sema] fix false -Wcomma being emited from void returning functions

[YingChi Long via Phabricator via cfe-commits]

inclyc updated this revision to Diff 452692.
inclyc added a comment.

typo


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D131892/new/

https://reviews.llvm.org/D131892

Files:
  clang/lib/Sema/SemaExpr.cpp
  clang/test/SemaCXX/warn-comma-operator.cpp


Index: clang/test/SemaCXX/warn-comma-operator.cpp
===================================================================
--- clang/test/SemaCXX/warn-comma-operator.cpp
+++ clang/test/SemaCXX/warn-comma-operator.cpp
@@ -140,6 +140,16 @@
   // CHECK: fix-it:{{.*}}:{[[@LINE-8]]:46-[[@LINE-8]]:46}:")"
 }
 
+
+void void_func();
+int int_func() { return 0; }
+
+void buggy(){
+  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
+}
+
 #ifdef __cplusplus
 class S2 {
 public:
Index: clang/lib/Sema/SemaExpr.cpp
===================================================================
--- clang/lib/Sema/SemaExpr.cpp
+++ 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<CastExpr>(E)) {
@@ -13973,6 +13975,9 @@
     }
   }
 
+  if (const CallExpr *CE = dyn_cast<CallExpr>(E))
+    if (const Type *T = CE->getCallReturnType(Context).getTypePtrOrNull())
+      return T->isVoidType();
   return false;
 }
 
@@ -14014,7 +14019,7 @@
   }
 
   // Only allow some expressions on LHS to not warn.
-  if (IgnoreCommaOperand(LHS))
+  if (IgnoreCommaOperand(LHS, Context))
     return;
 
   Diag(Loc, diag::warn_comma_operator);


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