diff --git a/lib/Format/UnwrappedLineParser.cpp b/lib/Format/UnwrappedLineParser.cpp
index 2ca4462..a01344c 100644
--- a/lib/Format/UnwrappedLineParser.cpp
+++ b/lib/Format/UnwrappedLineParser.cpp
@@ -684,7 +684,7 @@
     // (this would still leave us with an ambiguity between template function
     // and class declarations).
     if (FormatTok.Tok.is(tok::colon) || FormatTok.Tok.is(tok::less)) {
-      while (FormatTok.Tok.isNot(tok::l_brace)) {
+      while (!eof() && FormatTok.Tok.isNot(tok::l_brace)) {
         if (FormatTok.Tok.is(tok::semi))
           return;
         nextToken();
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index 40f0953..2a3d66d 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -2544,6 +2544,9 @@
                "  class X x;\n"
                "else\n"
                "  f();\n");
+
+  // This is simply incomplete. Formatting is not important, but must not crash.
+  verifyFormat("class A:"); 
 }
 
 TEST_F(FormatTest, DoNotInterfereWithErrorAndWarning) {