My clang now doesn't complain about !"foo".

src/pathops/SkPathOpsTypes.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef SkPathOpsTypes_DEFINED
 #define SkPathOpsTypes_DEFINED
 
 #include <float.h>  // for FLT_EPSILON
@@ skipping 209 matching lines @@
 struct SkDRect;
 
 inline SkPath::Verb SkPathOpsPointsToVerb(int points) {
     int verb = (1 << points) >> 1;
 #ifdef SK_DEBUG
     switch (points) {
         case 0: SkASSERT(SkPath::kMove_Verb == verb); break;
         case 1: SkASSERT(SkPath::kLine_Verb == verb); break;
         case 2: SkASSERT(SkPath::kQuad_Verb == verb); break;
         case 3: SkASSERT(SkPath::kCubic_Verb == verb); break;
-        default: SkASSERT(!"should not be here");
+        default: SkDEBUGFAIL("should not be here");
     }
 #endif
     return (SkPath::Verb)verb;
 }
 
 inline int SkPathOpsVerbToPoints(SkPath::Verb verb) {
     int points = (int) verb - ((int) verb >> 2);
 #ifdef SK_DEBUG
     switch (verb) {
         case SkPath::kLine_Verb: SkASSERT(1 == points); break;
         case SkPath::kQuad_Verb: SkASSERT(2 == points); break;
         case SkPath::kCubic_Verb: SkASSERT(3 == points); break;
-        default: SkASSERT(!"should not get here");
+        default: SkDEBUGFAIL("should not get here");
     }
 #endif
     return points;
 }
 
 inline double SkDInterp(double A, double B, double t) {
     return A + (B - A) * t;
 }
 
 double SkDCubeRoot(double x);
@@ skipping 14 matching lines @@
 */
 inline int SkDSideBit(double x) {
     return 1 << SKDSide(x);
 }
 
 inline double SkPinT(double t) {
     return precisely_less_than_zero(t) ? 0 : precisely_greater_than_one(t) ? 1 : t;
 }
 
 #endif