it can be return type of operations

Author: saschanaz

lib/productions/iterable.js

@@ -74,8 +74,8 @@ export class IterableLike extends Base {
       tokens.async &&
       tokens.base.value === "iterable"
     ) {
-      // Instead of a missing semicolon, this could be an invalid async iterable
-      // return type for a regular operation. Let's bail out early in that case.
+      // Instead of a missing semicolon, this could be an async iterable return
+      // type for a regular operation. Let's bail out early in that case.
       tokeniser.unconsume(start_position);
       return;
     } else if (!tokens.termination) {

lib/productions/operation.js

@@ -69,15 +69,6 @@ export class Operation extends Base {
     }
     if (this.idlType) {
       yield* this.idlType.validate(defs);
-      if (this.idlType.generic === "async iterable") {
-        const message = `Operations can not return ${this.idlType.generic} types.`;
-        yield validationError(
-          this.tokens.name,
-          this,
-          "operation-return-invalid-type",
-          message,
-        );
-      }
     }
     for (const argument of this.arguments) {
       yield* argument.validate(defs);

test/invalid/baseline/invalid-operation-return.txt

@@ -1 +1 @@
-callback DoSomething = Promise<DOMString> (async iterable<DOMString> bool);
+callback DoSomething = Promise<DOMString> (async iterable<DOMString> bool);

test/invalid/idl/invalid-callback-argument.webidl

@@ -124,6 +124,75 @@
         "extAttrs": [],
         "partial": false
     },
+    {
+        "type": "interface",
+        "name": "asyncIterableReturn",
+        "inheritance": null,
+        "members": [
+            {
+                "type": "operation",
+                "name": "stream",
+                "idlType": {
+                    "type": "return-type",
+                    "extAttrs": [],
+                    "generic": "async iterable",
+                    "nullable": false,
+                    "union": false,
+                    "idlType": [
+                        {
+                            "type": "return-type",
+                            "extAttrs": [],
+                            "generic": "",
+                            "nullable": false,
+                            "union": false,
+                            "idlType": "short"
+                        }
+                    ]
+                },
+                "arguments": [
+                    {
+                        "type": "argument",
+                        "name": "foo",
+                        "extAttrs": [],
+                        "idlType": {
+                            "type": "argument-type",
+                            "extAttrs": [],
+                            "generic": "async iterable",
+                            "nullable": false,
+                            "union": false,
+                            "idlType": [
+                                {
+                                    "type": "argument-type",
+                                    "extAttrs": [],
+                                    "generic": "",
+                                    "nullable": false,
+                                    "union": false,
+                                    "idlType": "short"
+                                }
+                            ]
+                        },
+                        "default": null,
+                        "optional": false,
+                        "variadic": false
+                    }
+                ],
+                "extAttrs": [],
+                "special": ""
+            }
+        ],
+        "extAttrs": [
+            {
+                "type": "extended-attribute",
+                "name": "Exposed",
+                "rhs": {
+                    "type": "identifier",
+                    "value": "Window"
+                },
+                "arguments": []
+            }
+        ],
+        "partial": false
+    },
     {
         "type": "eof",
         "value": ""

test/invalid/idl/invalid-operation-return.webidl

@@ -5,3 +5,8 @@ interface Canvas {
 interface I {
   Promise<undefined> f1(async iterable<[XAttr] float> arg);
 };
+
+[Exposed=Window]
+interface asyncIterableReturn {
+  async iterable<short> stream(async iterable<short> foo);
+};