Incorrect parse error for async methods with keywords as names

[not-an-aardvark]

When parsing an async method in an object that has a keyword as a name, acorn incorrectly reports a parsing error. This only seems to apply when parsing object methods -- class methods are parsed correctly.

Using acorn 5.1.1:

require('acorn').parse('({ async delete() {} })', { ecmaVersion: 8 });

Expected AST

{
  "type": "Program",
  "start": 0,
  "end": 20,
  "body": [
    {
      "type": "ExpressionStatement",
      "start": 0,
      "end": 20,
      "expression": {
        "type": "ObjectExpression",
        "start": 1,
        "end": 19,
        "properties": [
          {
            "type": "Property",
            "start": 2,
            "end": 18,
            "method": true,
            "shorthand": false,
            "computed": false,
            "key": {
              "type": "Identifier",
              "start": 8,
              "end": 14,
              "name": "delete"
            },
            "kind": "init",
            "value": {
              "type": "FunctionExpression",
              "start": 14,
              "end": 18,
              "id": null,
              "generator": false,
              "expression": false,
              "async": true,
              "params": [],
              "body": {
                "type": "BlockStatement",
                "start": 16,
                "end": 18,
                "body": []
              }
            }
          }
        ]
      }
    }
  ],
  "sourceType": "script"
}

Actual result

SyntaxError: Unexpected token (1:9)

This was originally reported in eslint/eslint#9153.

[not-an-aardvark]

Thanks for fixing!

[Standard8]

@marijnh Would it be possible to get a new release including this fix? We have issues that we want to resolve with dependencies, but this fix is blocking us.

[marijnh]

I've tagged 5.1.2

[Standard8]

Thank you!