clang-format: Fix crasher.

llvm-svn: 229485
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 242d2ba..52761f1 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -5818,6 +5818,7 @@
 TEST_F(FormatTest, IncorrectCodeUnbalancedBraces) {
   verifyFormat("{");
   verifyFormat("#})");
+  verifyNoCrash("(/**/[:!] ?[).");
 }
 
 TEST_F(FormatTest, IncorrectCodeDoNoWhile) {