Fix invalid setter parse (#12076)

* Fix invalid `setter` parse

* estree

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

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

@@ -1795,12 +1795,20 @@ export default class ExpressionParser extends LValParser {
     return method.kind === "get" ? 0 : 1;
   }
 
+  // This exists so we can override within the ESTree plugin
+  getObjectOrClassMethodParams(method: N.ObjectMethod | N.ClassMethod) {
+    return method.params;
+  }
+
   // get methods aren't allowed to have any parameters
   // set methods must have exactly 1 parameter which is not a rest parameter
   checkGetterSetterParams(method: N.ObjectMethod | N.ClassMethod): void {
     const paramCount = this.getGetterSetterExpectedParamCount(method);
+    const params = this.getObjectOrClassMethodParams(method);
+
     const start = method.start;
-    if (method.params.length !== paramCount) {
+
+    if (params.length !== paramCount) {
       if (method.kind === "get") {
         this.raise(start, Errors.BadGetterArity);
       } else {
@@ -1810,7 +1818,7 @@ export default class ExpressionParser extends LValParser {
 
     if (
       method.kind === "set" &&
-      method.params[method.params.length - 1].type === "RestElement"
+      params[params.length - 1]?.type === "RestElement"
     ) {
       this.raise(start, Errors.BadSetterRestParameter);
     }

packages/babel-parser/src/plugins/estree.js

@@ -105,22 +105,9 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       }
     }
 
-    checkGetterSetterParams(method: N.ObjectMethod | N.ClassMethod): void {
+    getObjectOrClassMethodParams(method: N.ObjectMethod | N.ClassMethod) {
-      const prop = ((method: any): N.EstreeProperty | N.EstreeMethodDefinition);
+      return ((method: any): N.EstreeProperty | N.EstreeMethodDefinition).value
-      const paramCount = prop.kind === "get" ? 0 : 1;
+        .params;
-      const start = prop.start;
-      if (prop.value.params.length !== paramCount) {
-        if (method.kind === "get") {
-          this.raise(start, Errors.BadGetterArity);
-        } else {
-          this.raise(start, Errors.BadSetterArity);
-        }
-      } else if (
-        prop.kind === "set" &&
-        prop.value.params[0].type === "RestElement"
-      ) {
-        this.raise(start, Errors.BadSetterRestParameter);
-      }
     }
 
     checkLVal(

packages/babel-parser/test/fixtures/core/object/invalid-setter/input.js

@@ -0,0 +1 @@
+({ set x(){} })

packages/babel-parser/test/fixtures/core/object/invalid-setter/output.json

@@ -0,0 +1,52 @@
+{
+  "type": "File",
+  "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+  "errors": [
+    "SyntaxError: setter must have exactly one formal parameter (1:3)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+        "expression": {
+          "type": "ObjectExpression",
+          "start":1,"end":14,"loc":{"start":{"line":1,"column":1},"end":{"line":1,"column":14}},
+          "properties": [
+            {
+              "type": "ObjectMethod",
+              "start":3,"end":12,"loc":{"start":{"line":1,"column":3},"end":{"line":1,"column":12}},
+              "method": false,
+              "key": {
+                "type": "Identifier",
+                "start":7,"end":8,"loc":{"start":{"line":1,"column":7},"end":{"line":1,"column":8},"identifierName":"x"},
+                "name": "x"
+              },
+              "computed": false,
+              "kind": "set",
+              "id": null,
+              "generator": false,
+              "async": false,
+              "params": [],
+              "body": {
+                "type": "BlockStatement",
+                "start":10,"end":12,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":12}},
+                "body": [],
+                "directives": []
+              }
+            }
+          ],
+          "extra": {
+            "parenthesized": true,
+            "parenStart": 0
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/estree/object-method/invalid-setter/input.js

@@ -0,0 +1 @@
+({ set x(){} })

packages/babel-parser/test/fixtures/estree/object-method/invalid-setter/output.json

@@ -0,0 +1,56 @@
+{
+  "type": "File",
+  "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+  "errors": [
+    "SyntaxError: setter must have exactly one formal parameter (1:3)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+        "expression": {
+          "type": "ObjectExpression",
+          "start":1,"end":14,"loc":{"start":{"line":1,"column":1},"end":{"line":1,"column":14}},
+          "properties": [
+            {
+              "type": "Property",
+              "start":3,"end":12,"loc":{"start":{"line":1,"column":3},"end":{"line":1,"column":12}},
+              "method": false,
+              "key": {
+                "type": "Identifier",
+                "start":7,"end":8,"loc":{"start":{"line":1,"column":7},"end":{"line":1,"column":8},"identifierName":"x"},
+                "name": "x"
+              },
+              "computed": false,
+              "kind": "set",
+              "value": {
+                "type": "FunctionExpression",
+                "start":8,"end":12,"loc":{"start":{"line":1,"column":8},"end":{"line":1,"column":12}},
+                "id": null,
+                "generator": false,
+                "async": false,
+                "expression": false,
+                "params": [],
+                "body": {
+                  "type": "BlockStatement",
+                  "start":10,"end":12,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":12}},
+                  "body": []
+                }
+              },
+              "shorthand": false
+            }
+          ],
+          "extra": {
+            "parenthesized": true,
+            "parenStart": 0
+          }
+        }
+      }
+    ]
+  }
+}