Index: clang/lib/StaticAnalyzer/Checkers/CStringChecker.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Checkers/CStringChecker.cpp
+++ clang/lib/StaticAnalyzer/Checkers/CStringChecker.cpp
@@ -268,11 +268,17 @@
                            QualType Ty) {
   Optional<DefinedSVal> val = V.getAs<DefinedSVal>();
   if (!val)
-    return std::pair<ProgramStateRef , ProgramStateRef >(state, state);
+    return std::pair<ProgramStateRef, ProgramStateRef>(state, state);
 
   SValBuilder &svalBuilder = C.getSValBuilder();
   DefinedOrUnknownSVal zero = svalBuilder.makeZeroVal(Ty);
-  return state->assume(svalBuilder.evalEQ(state, *val, zero));
+
+  // equality operation is only acceptable between the same types
+  if (V.getAs<Loc>() && zero.getAs<Loc>() ||
+      V.getAs<NonLoc>() && zero.getAs<NonLoc>())
+    return state->assume(svalBuilder.evalEQ(state, *val, zero));
+
+  return std::pair<ProgramStateRef, ProgramStateRef>(state, state);
 }
 
 ProgramStateRef CStringChecker::checkNonNull(CheckerContext &C,