Improve the unused-value check to look into comma expressions and filter out

voids in sub-expressions.  Patch by Mike M!

Fixes PR4806.

llvm-svn: 98335

1 files changed, 3 insertions, 4 deletions

diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index 75d9f67ad9d..fd65c32c203 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -76,10 +76,6 @@ void Sema::DiagnoseUnusedExprResult(const Stmt *S) {
   if (!E)
     return;
 
-  // Ignore expressions that have void type.
-  if (E->getType()->isVoidType())
-    return;
-
   SourceLocation Loc;
   SourceRange R1, R2;
   if (!E->isUnusedResultAWarning(Loc, R1, R2, Context))
@@ -103,6 +99,9 @@ void Sema::DiagnoseUnusedExprResult(const Stmt *S) {
   }
       
   if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
+    if (E->getType()->isVoidType())
+      return;
+
     // If the callee has attribute pure, const, or warn_unused_result, warn with
     // a more specific message to make it clear what is happening.
     if (const Decl *FD = CE->getCalleeDecl()) {