Make the parser error recoverable

packages/babel-parser/src/parse-error/standard-errors.ts

@@ -50,6 +50,8 @@ export default {
   }: {
     kind: "const" | "destructuring";
   }) => `Missing initializer in ${kind} declaration.`,
+  DecoratorArgumentsOutsideParentheses:
+    "Decorator arguments must be moved inside parentheses: use '@(decorator(args))' instead of '@(decorator)(args)'.",
   DecoratorBeforeExport:
     "Decorators must be placed *before* the 'export' keyword. You can set the 'decoratorsBeforeExport' option to false to use the 'export @decorator class {}' syntax.",
   DecoratorConstructor:

packages/babel-parser/src/parser/statement.ts

@@ -581,12 +581,16 @@ export default abstract class StatementParser extends ExpressionParser {
         this.expect(tt.parenR);
         expr = this.wrapParenthesis(startPos, startLoc, expr);
 
+        const paramsStartLoc = this.state.startLoc;
+        node.expression = this.parseMaybeDecoratorArguments(expr);
         if (
-          this.getPluginOption("decorators", "allowCallParenthesized") !== false
+          this.getPluginOption("decorators", "allowCallParenthesized") ===
+            false &&
+          node.expression !== expr
         ) {
-          node.expression = this.parseMaybeDecoratorArguments(expr);
-        } else {
-          node.expression = expr;
+          this.raise(Errors.DecoratorArgumentsOutsideParentheses, {
+            at: paramsStartLoc,
+          });
         }
       } else {
         expr = this.parseIdentifier(false);

packages/babel-parser/test/fixtures/experimental/decorators/parenthesized-allowCallParenthesized-false-invalid/options.json

@@ -7,6 +7,5 @@
         "decoratorsBeforeExport": false
       }
     ]
-  ],
-  "throws": "Unexpected token (2:13)"
+  ]
 }

packages/babel-parser/test/fixtures/experimental/decorators/parenthesized-allowCallParenthesized-false-invalid/output.json

@@ -0,0 +1,89 @@
+{
+  "type": "File",
+  "start":0,"end":45,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":3,"column":1,"index":45}},
+  "errors": [
+    "SyntaxError: Decorator arguments must be moved inside parentheses: use '@(decorator(args))' instead of '@(decorator)(args)'. (2:13)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":45,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":3,"column":1,"index":45}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start":0,"end":45,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":3,"column":1,"index":45}},
+        "id": {
+          "type": "Identifier",
+          "start":6,"end":9,"loc":{"start":{"line":1,"column":6,"index":6},"end":{"line":1,"column":9,"index":9},"identifierName":"Foo"},
+          "name": "Foo"
+        },
+        "superClass": null,
+        "body": {
+          "type": "ClassBody",
+          "start":10,"end":45,"loc":{"start":{"line":1,"column":10,"index":10},"end":{"line":3,"column":1,"index":45}},
+          "body": [
+            {
+              "type": "ClassMethod",
+              "start":14,"end":43,"loc":{"start":{"line":2,"column":2,"index":14},"end":{"line":2,"column":31,"index":43}},
+              "decorators": [
+                {
+                  "type": "Decorator",
+                  "start":14,"end":30,"loc":{"start":{"line":2,"column":2,"index":14},"end":{"line":2,"column":18,"index":30}},
+                  "expression": {
+                    "type": "CallExpression",
+                    "start":16,"end":30,"loc":{"start":{"line":2,"column":4,"index":16},"end":{"line":2,"column":18,"index":30}},
+                    "callee": {
+                      "type": "MemberExpression",
+                      "start":16,"end":24,"loc":{"start":{"line":2,"column":4,"index":16},"end":{"line":2,"column":12,"index":24}},
+                      "object": {
+                        "type": "ThisExpression",
+                        "start":16,"end":20,"loc":{"start":{"line":2,"column":4,"index":16},"end":{"line":2,"column":8,"index":20}}
+                      },
+                      "computed": false,
+                      "property": {
+                        "type": "Identifier",
+                        "start":21,"end":24,"loc":{"start":{"line":2,"column":9,"index":21},"end":{"line":2,"column":12,"index":24},"identifierName":"foo"},
+                        "name": "foo"
+                      },
+                      "extra": {
+                        "parenthesized": true,
+                        "parenStart": 15
+                      }
+                    },
+                    "arguments": [
+                      {
+                        "type": "Identifier",
+                        "start":26,"end":29,"loc":{"start":{"line":2,"column":14,"index":26},"end":{"line":2,"column":17,"index":29},"identifierName":"bar"},
+                        "name": "bar"
+                      }
+                    ]
+                  }
+                }
+              ],
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start":31,"end":38,"loc":{"start":{"line":2,"column":19,"index":31},"end":{"line":2,"column":26,"index":38},"identifierName":"method3"},
+                "name": "method3"
+              },
+              "computed": false,
+              "kind": "method",
+              "id": null,
+              "generator": false,
+              "async": false,
+              "params": [],
+              "body": {
+                "type": "BlockStatement",
+                "start":41,"end":43,"loc":{"start":{"line":2,"column":29,"index":41},"end":{"line":2,"column":31,"index":43}},
+                "body": [],
+                "directives": []
+              }
+            }
+          ]
+        }
+      }
+    ],
+    "directives": []
+  }
+}