refactor: add recoverable error on accessorIsGenerator (#11921)

* refactor: add recoverable error on accessorIsGenerator

* Update packages/babel-parser/src/parser/error-message.js

Co-authored-by: Brian Ng <bng412@gmail.com>

* Apply suggestions from code review

Co-authored-by: Brian Ng <bng412@gmail.com>

packages/babel-parser/src/parser/error-message.js

@@ -3,6 +3,7 @@
 
 // The Errors key follows https://cs.chromium.org/chromium/src/v8/src/common/message-template.h unless it does not exist
 export const ErrorMessages = Object.freeze({
+  AccessorIsGenerator: "A %0ter cannot be a generator",
   ArgumentsDisallowedInInitializer:
     "'arguments' is not allowed in class field initializer",
   AsyncFunctionInSingleStatementContext:

packages/babel-parser/src/parser/expression.js

@@ -1757,8 +1757,11 @@ export default class ExpressionParser extends LValParser {
       // set PropertyName[?Yield, ?Await] ( PropertySetParameterList ) { FunctionBody[~Yield, ~Await] }
       if (keyName === "get" || keyName === "set") {
         isAccessor = true;
-        isGenerator = this.eat(tt.star); // tt.star is allowed in `maybeAsyncOrAccessorProp`, we will throw in `parseObjectMethod` later
         prop.kind = keyName;
+        if (this.match(tt.star)) {
+          this.raise(this.state.pos, Errors.AccessorIsGenerator, keyName);
+          this.next();
+        }
         this.parsePropertyName(prop, /* isPrivateNameAllowed */ false);
       }
     }
@@ -1813,8 +1816,7 @@ export default class ExpressionParser extends LValParser {
     isAccessor: boolean,
   ): ?N.ObjectMethod {
     if (isAccessor) {
-      // isAccessor implies isAsync: false, isPattern: false
+      // isAccessor implies isAsync: false, isPattern: false, isGenerator: false
-      if (isGenerator) this.unexpected();
       this.parseMethod(
         prop,
         /* isGenerator */ false,

packages/babel-parser/test/fixtures/es2015/object/invalid-accessor-generator/input.js

@@ -0,0 +1,4 @@
+({
+    get *iterator() { },
+    set *iterator(iter) { }
+})

packages/babel-parser/test/fixtures/es2015/object/invalid-accessor-generator/output.json

@@ -0,0 +1,81 @@
+{
+  "type": "File",
+  "start":0,"end":58,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":2}},
+  "errors": [
+    "SyntaxError: A getter cannot be a generator (2:9)",
+    "SyntaxError: A setter cannot be a generator (3:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":58,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":2}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":58,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":2}},
+        "expression": {
+          "type": "ObjectExpression",
+          "start":1,"end":57,"loc":{"start":{"line":1,"column":1},"end":{"line":4,"column":1}},
+          "properties": [
+            {
+              "type": "ObjectMethod",
+              "start":7,"end":26,"loc":{"start":{"line":2,"column":4},"end":{"line":2,"column":23}},
+              "method": false,
+              "key": {
+                "type": "Identifier",
+                "start":12,"end":20,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":17},"identifierName":"iterator"},
+                "name": "iterator"
+              },
+              "computed": false,
+              "kind": "get",
+              "id": null,
+              "generator": false,
+              "async": false,
+              "params": [],
+              "body": {
+                "type": "BlockStatement",
+                "start":23,"end":26,"loc":{"start":{"line":2,"column":20},"end":{"line":2,"column":23}},
+                "body": [],
+                "directives": []
+              }
+            },
+            {
+              "type": "ObjectMethod",
+              "start":32,"end":55,"loc":{"start":{"line":3,"column":4},"end":{"line":3,"column":27}},
+              "method": false,
+              "key": {
+                "type": "Identifier",
+                "start":37,"end":45,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":17},"identifierName":"iterator"},
+                "name": "iterator"
+              },
+              "computed": false,
+              "kind": "set",
+              "id": null,
+              "generator": false,
+              "async": false,
+              "params": [
+                {
+                  "type": "Identifier",
+                  "start":46,"end":50,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":22},"identifierName":"iter"},
+                  "name": "iter"
+                }
+              ],
+              "body": {
+                "type": "BlockStatement",
+                "start":52,"end":55,"loc":{"start":{"line":3,"column":24},"end":{"line":3,"column":27}},
+                "body": [],
+                "directives": []
+              }
+            }
+          ],
+          "extra": {
+            "parenthesized": true,
+            "parenStart": 0
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}