Index: cfe/trunk/lib/Format/TokenAnnotator.cpp
===================================================================
--- cfe/trunk/lib/Format/TokenAnnotator.cpp
+++ cfe/trunk/lib/Format/TokenAnnotator.cpp
@@ -533,6 +533,7 @@
             Contexts.back().ContextKind == tok::l_square || // array type
             (Contexts.size() == 1 &&
              Line.MustBeDeclaration)) { // method/property declaration
+          Contexts.back().IsExpression = false;
           Tok->Type = TT_JsTypeColon;
           break;
         }
Index: cfe/trunk/unittests/Format/FormatTestJS.cpp
===================================================================
--- cfe/trunk/unittests/Format/FormatTestJS.cpp
+++ cfe/trunk/unittests/Format/FormatTestJS.cpp
@@ -988,6 +988,9 @@
                "    .doSomethingElse(\n"
                "        // break\n"
                "    );");
+  verifyFormat("const f = (x: string|null): string|null => {\n"
+               "  return x;\n"
+               "}\n");
 }
 
 TEST_F(FormatTestJS, ReturnStatements) {