Index: unittests/Format/FormatTestJS.cpp
===================================================================
--- unittests/Format/FormatTestJS.cpp
+++ unittests/Format/FormatTestJS.cpp
@@ -936,6 +936,9 @@
                "    return 'y';\n"
                "  }\n"
                "}");
+  verifyFormat("class C {\n"
+               "  private x(@A x: string) {}\n"
+               "}");
   verifyFormat("class X {}\n"
                "class Y {}");
 }