Disallow 'yield' in async arrow parameter lists inside generators

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 658e73ca84adf2869e01019c6a05bb07ff400225..c73341c77f584732ccec16ac76d65d3df8a1118c 100644
--- a/test/cctest/test-parsing.cc
+++ b/test/cctest/test-parsing.cc
@@ -7685,6 +7685,9 @@ TEST(AsyncAwait) {
 
     "var asyncFn = async({ foo = 1 }) => foo;",
     "var asyncFn = async({ foo = 1 } = {}) => foo;",
+
+    "function* g() { var f = async(yield); }",
+    "function* g() { var f = async(x = yield); }",
     NULL
   };
   // clang-format on
@@ -7792,6 +7795,11 @@ TEST(AsyncAwaitErrors) {
 
     "var f = async(x = await) => 1;",
 
+    "function* g() { var f = async yield => 1; }",
+    "function* g() { var f = async(yield) => 1; }",
+    "function* g() { var f = async(x = yield) => 1; }",
+    "function* g() { var f = async({x = yield}) => 1; }",
+
     "class C { async constructor() {} }",
     "class C {}; class C2 extends C { async constructor() {} }",
     "class C { static async prototype() {} }",