Disallow tail calls from async functions and generators

test/mjsunit/es8/syntactic-tail-call-parsing.js

Index: test/mjsunit/es8/syntactic-tail-call-parsing.js
diff --git a/test/mjsunit/es8/syntactic-tail-call-parsing.js b/test/mjsunit/es8/syntactic-tail-call-parsing.js
index 9ceff9c59649ba1bfa451e9743f8a8e9d0381ef7..486c3e1da6e29a62e94cbd20e8230a9b09111f4f 100644
--- a/test/mjsunit/es8/syntactic-tail-call-parsing.js
+++ b/test/mjsunit/es8/syntactic-tail-call-parsing.js
@@ -3,7 +3,7 @@
 // found in the LICENSE file.
 
 // Flags: --allow-natives-syntax --harmony-explicit-tailcalls
-// Flags: --harmony-do-expressions
+// Flags: --harmony-do-expressions --harmony-async-await
 "use strict";
 
 var SyntaxErrorTests = [
@@ -128,7 +128,10 @@ var SyntaxErrorTests = [
         err: `                    ^^^^^^^^^^^^^^`,
       },
       { src: `()=>{ function* G() { yield continue foo(); } }`,
-        err: `                            ^^^^^^^^^^^^^^`,
+        err: `                                     ^^^^^`,
+      },
+      { src: `()=>{ function* G() { return continue foo(); } }`,
+        err: `                                      ^^^^^`,
       },
       { src: `()=>{ (1, 2, 3, continue f() ) => {} }`,
         err: `                ^^^^^^^^^^^^`,
@@ -235,6 +238,9 @@ var SyntaxErrorTests = [
       { src: `class A extends continue f () {}; }`,
         err: `                ^^^^^^^^^^^^^`,
       },
+      { src: `async() => continue foo()`,
+        err: `                    ^^^^^`,
+      },
     ],
   },
   { msg: "Tail call expression in try block",
@@ -311,7 +317,6 @@ var NoErrorTests = [
   `()=>{ return a || continue f() ; }`,
   `()=>{ return a && continue f() ; }`,
   `()=>{ return a , continue f() ; }`,
-  `()=>{ function* G() { return continue foo(); } }`,
   `()=>{ class A { foo() { return continue super.f() ; } } }`,
   `()=>{ function B() { return continue new.target() ; } }`,
   `()=>{ return continue do { x ? foo() : bar() ; }() }`,