Improve understanding post increment and decrement.

Before: (a->f()) ++;
        a[42] ++;
After:  (a->f())++;
        a[42]++;

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@172400 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Format/Format.cpp b/lib/Format/Format.cpp
index 548bdee..57e9a76 100644
--- a/lib/Format/Format.cpp
+++ b/lib/Format/Format.cpp
@@ -1060,7 +1060,10 @@
 
   /// \brief Determine whether ++/-- are pre- or post-increments/-decrements.
   TokenType determineIncrementUsage(const AnnotatedToken &Tok) {
-    if (Tok.Parent != NULL && Tok.Parent->is(tok::identifier))
+    if (Tok.Parent == NULL)
+      return TT_UnaryOperator;
+    if (Tok.Parent->is(tok::r_paren) || Tok.Parent->is(tok::r_square) ||
+        Tok.Parent->is(tok::identifier))
       return TT_TrailingUnaryOperator;
 
     return TT_UnaryOperator;