fix(callback-interface): apply member type restriction

lib/productions/callback-interface.js

@@ -0,0 +1,29 @@
+import { Container } from "./container.js";
+import { Operation } from "./operation.js";
+import { Constant } from "./constant.js";
+
+
+export class CallbackInterface extends Container {
+  /**
+   * @param {import("../tokeniser").Tokeniser} tokeniser
+   */
+  static parse(tokeniser, callback, { partial = null } = {}) {
+    const tokens = { callback };
+    tokens.base = tokeniser.consume("interface");
+    if (!tokens.base) {
+      return;
+    }
+    return Container.parse(tokeniser, new CallbackInterface({ source: tokeniser.source, tokens }), {
+      type: "callback interface",
+      inheritable: !partial,
+      allowedMembers: [
+        [Constant.parse],
+        [Operation.parse, { regular: true }]
+      ]
+    });
+  }
+
+  get type() {
+    return "callback interface";
+  }
+}

lib/productions/interface.js

@@ -21,8 +21,8 @@ export class Interface extends Container {
   /**
    * @param {import("../tokeniser").Tokeniser} tokeniser
    */
-  static parse(tokeniser, base, { callback = null, partial = null } = {}) {
-    const tokens = { callback, partial, base };
+  static parse(tokeniser, base, { partial = null } = {}) {
+    const tokens = { partial, base };
     return Container.parse(tokeniser, new Interface({ source: tokeniser.source, tokens }), {
       type: "interface",
       inheritable: !partial,
@@ -38,9 +38,6 @@ export class Interface extends Container {
   }
 
   get type() {
-    if (this.tokens.callback) {
-      return "callback interface";
-    }
     return "interface";
   }
 }

lib/webidl2.js

@@ -10,6 +10,7 @@ import { Interface } from "./productions/interface.js";
 import { Mixin } from "./productions/mixin.js";
 import { Dictionary } from "./productions/dictionary.js";
 import { Namespace } from "./productions/namespace.js";
+import { CallbackInterface } from "./productions/callback-interface.js";
 
 /**
  * @param {Tokeniser} tokeniser
@@ -30,9 +31,8 @@ function parseByTokens(tokeniser, options) {
   function callback() {
     const callback = consume("callback");
     if (!callback) return;
-    const tok = consume("interface");
-    if (tok) {
-      return Interface.parse(tokeniser, tok, { callback });
+    if (tokeniser.probe("interface")) {
+      return CallbackInterface.parse(tokeniser, callback);
     }
     return CallbackFunction.parse(tokeniser, callback);
   }

test/invalid/baseline/callback-attribute.txt

@@ -0,0 +1,3 @@
+Syntax error at line 2, since `callback interface Attribute`:
+  attribute boolean attr;
+  ^ Missing return type

test/invalid/baseline/no-semicolon-callback.txt

@@ -1,3 +1,3 @@
 Syntax error at line 5, since `callback interface NoSemicolon`:
 enum YouNeedOne {
-^ Missing semicolon after interface
+^ Missing semicolon after callback interface

test/invalid/idl/callback-attribute.widl

@@ -0,0 +1,3 @@
+callback interface Attribute {
+  attribute boolean attr;
+};

test/invalid/idl/no-semicolon-callback.widl

@@ -1,5 +1,5 @@
 callback interface NoSemicolon {
-  attribute boolean noSemiColon;
+  void noSemiColon();
 }
 
 enum YouNeedOne {