Fix crash for incomplete labels in macros.

Still the formatting can be improved, but at least we don't assert any
more. This happened when trying to format lib/Sema/SemaType.cpp.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@175003 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Format/UnwrappedLineParser.cpp b/lib/Format/UnwrappedLineParser.cpp
index 9226716..28522a3 100644
--- a/lib/Format/UnwrappedLineParser.cpp
+++ b/lib/Format/UnwrappedLineParser.cpp
@@ -565,8 +565,8 @@
 }
 
 void UnwrappedLineParser::parseLabel() {
-  // FIXME: remove all asserts.
-  assert(FormatTok.Tok.is(tok::colon) && "':' expected");
+  if (FormatTok.Tok.isNot(tok::colon))
+    return;
   nextToken();
   unsigned OldLineLevel = Line->Level;
   if (Line->Level > 0)
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index f1cef2a..f28bc88 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -353,6 +353,12 @@
                "}");
   verifyFormat("switch (test)\n"
                "  ;");
+  
+  // FIXME: Improve formatting of case labels in macros.
+  verifyFormat("#define SOMECASES  \\\n"
+               "case 1:            \\\n"
+               "  case 2\n", getLLVMStyleWithColumns(20));
+
   verifyGoogleFormat("switch (x) {\n"
                      "  case 1:\n"
                      "    f();\n"