Index: lib/Format/UnwrappedLineParser.cpp
===================================================================
--- lib/Format/UnwrappedLineParser.cpp
+++ lib/Format/UnwrappedLineParser.cpp
@@ -350,7 +350,10 @@
       break;
     case tok::kw_default: {
       unsigned StoredPosition = Tokens->getPosition();
-      FormatToken *Next = Tokens->getNextToken();
+      FormatToken *Next;
+      do {
+        Next = Tokens->getNextToken();
+      } while (Next && Next->is(tok::comment));
       FormatTok = Tokens->setPosition(StoredPosition);
       if (Next && Next->isNot(tok::colon)) {
         // default not followed by ':' is not a case label; treat it like
Index: unittests/Format/FormatTest.cpp
===================================================================
--- unittests/Format/FormatTest.cpp
+++ unittests/Format/FormatTest.cpp
@@ -1112,6 +1112,20 @@
                    "case 0: return; /* long long long long long long long long long long long long comment line */\n"
                    "}",
                    Style));
+
+  EXPECT_EQ("switch (n) {\n"
+            "  default /*comments*/:\n"
+            "    return true;\n"
+            "  case 0:\n"
+            "    return false;\n"
+            "}",
+            format("switch (n) {\n"
+                   "  default /*comments*/:\n"
+                   "    return true;\n"
+                   "    case 0:\n"
+                   "      return false;\n"
+                   "}",
+                   Style));
   verifyFormat("switch (a) {\n"
                "#if FOO\n"
                "case 0: return 0;\n"