Fix formatting of overloaded assignment operators.

Before: SomeType &operator=(const SomeType & S);
After:  SomeType &operator=(const SomeType &S);

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179270 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Format/TokenAnnotator.cpp b/lib/Format/TokenAnnotator.cpp
index 42cbf04..08d9b10 100644
--- a/lib/Format/TokenAnnotator.cpp
+++ b/lib/Format/TokenAnnotator.cpp
@@ -563,7 +563,8 @@
   };
 
   void determineTokenType(AnnotatedToken &Current) {
-    if (getPrecedence(Current) == prec::Assignment) {
+    if (getPrecedence(Current) == prec::Assignment &&
+        (!Current.Parent || Current.Parent->isNot(tok::kw_operator))) {
       Contexts.back().IsExpression = true;
       for (AnnotatedToken *Previous = Current.Parent;
            Previous && Previous->isNot(tok::comma);