[parser] report errors for invalid binding patterns in async formal parameters

test/cctest/test-parsing.cc

Index: test/cctest/test-parsing.cc
diff --git a/test/cctest/test-parsing.cc b/test/cctest/test-parsing.cc
index 9f7e889968481f85d03986264ff9bf746b27a342..7f3f908b910e4b258ec14efa47b6ca2069af7916 100644
--- a/test/cctest/test-parsing.cc
+++ b/test/cctest/test-parsing.cc
@@ -7710,6 +7710,14 @@ TEST(AsyncAwaitErrors) {
     "var f = async(await) => 1;",
     "var f = async(await = 1) => 1;",
     "var f = async(...[await]) => 1;",
+
+    // v8:5190
+    "var f = async(1) => 1",
+    "var f = async('str') => 1",
+    "var f = async(/foo/) => 1",
+    "var f = async({ foo = async(1) => 1 }) => 1",
+    "var f = async({ foo = async(a) => 1 })",

[Dan Ehrenberg, 2016/07/11 23:22:47]

How is this last error related to your patch?

[caitp, 2016/07/11 23:32:24]

The idea is to make sure that even though async arrow functions still work
correctly, async calls also still work correctly and don't incorrectly report
errors that they should not.

+
     NULL
   };
   // clang-format on