Parse record declarations with token pasted identifiers.

This is pretty common in macros:
 #define A(X, Y) class X##Y {};

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@174512 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index cd3bf17..fc95acc 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -1859,6 +1859,7 @@
   verifyFormat("class MACRO(X) Z {\n} n;");
   verifyFormat("class __attribute__(X) Z {\n} n;");
   verifyFormat("class __declspec(X) Z {\n} n;");
+  verifyFormat("class A##B##C {\n} n;");
 
   // Redefinition from nested context:
   verifyFormat("class A::B::C {\n} n;");