fix PR5933: don't warn about unused variables if a function has other errors in it.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@97498 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 8 insertions, 1 deletions

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index be4a591f29..4842da2a7b 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -553,7 +553,8 @@ void Sema::ActOnPopScope(SourceLocation Loc, Scope *S) {
     if (!D->getDeclName()) continue;
 
     // Diagnose unused variables in this scope.
-    if (ShouldDiagnoseUnusedDecl(D))
+    if (ShouldDiagnoseUnusedDecl(D) &&
+        NumErrorsAtStartOfFunction == getDiagnostics().getNumErrors())
       Diag(D->getLocation(), diag::warn_unused_variable) << D->getDeclName();
     
     // Remove this name from our lexical scope.
diff --git a/test/Sema/warn-unused-variables.c b/test/Sema/warn-unused-variables.c
index 36615061fe..4d1cde7067 100644
--- a/test/Sema/warn-unused-variables.c
+++ b/test/Sema/warn-unused-variables.c
@@ -17,3 +17,9 @@ void f1(void) {
 	(void)sizeof(i);
 	return;
 }
+
+// PR5933
+int f2() {
+  int X = 4;  // Shouldn't have a bogus 'unused variable X' warning.
+  return Y + X; // expected-error {{use of undeclared identifier 'Y'}}
+}