Don't warn -Wsign-compare if we're in an unevaluated context, and fixed

a typo pointed out by Fariborz.

llvm-svn: 86265

clang/include/clang/Basic/DiagnosticGroups.td

@@ -160,6 +160,6 @@ def : DiagGroup<"", [Extra]>;  // -W = -Wextra
 def : DiagGroup<"endif-labels", [ExtraTokens]>; // endif-labels = endif-tokens
 
 // A warning group for warnings that we want to have on by default in clang,
-// but which aren't no by default in GCC.
+// but which aren't on by default in GCC.
 def NonGCC : DiagGroup<"non-gcc",
     [SignCompare]>;

clang/lib/Sema/SemaExpr.cpp

@@ -4454,6 +4454,10 @@ QualType Sema::CheckShiftOperands(Expr *&lex, Expr *&rex, SourceLocation Loc,
 ///   suppresses the warning in some cases
 void Sema::CheckSignCompare(Expr *lex, Expr *rex, SourceLocation OpLoc,
                             const PartialDiagnostic &PD, bool Equality) {
+  // Don't warn if we're in an unevaluated context.
+  if (ExprEvalContext == Unevaluated)
+    return;
+
   QualType lt = lex->getType(), rt = rex->getType();
 
   // Only warn if both operands are integral.