Previously we parsed arrow functions without the relevant cover grammar `CoverParenthesizedExpressionAndArrowParameterList`. This leads to either arrow functions or parenthesized expressions not being parsed correctly. Implementing this is a bit tricky, as the cover grammar is being parsed in `PrimaryExpression` while arrow functions are parsed in `AssignmentExpression`. This means that we have to return the covered parameter list that was parsed via `CoverParenthesizedExpressionAndArrowParameterList` in `PrimaryExpression` to `AssignmentExpression`. Fortunately this works pretty good and now the full arrow function test suite, with the exception of a few tests that require other features, passes.
This Pull Request changes the following:
- Implement `CoverParenthesizedExpressionAndArrowParameterList` parsing.
- Implement `CoverInitializedName` parsing in object literals.
- Fix a bug where an environment would be wrongly removed from the environment stack when an expression in default function parameters throws.
- Add more valid cases where on object literal can be converted to an object declaration pattern.
- Implement `Expression` parsing manually to avoid some cases where the parser would prematurely throw an error.
- Implement parsing of arrow functions via `CoverParenthesizedExpressionAndArrowParameterList`.
- Remove unneeded `AllowIn` flag on array and object declaration pattern parsers.
- Fix an of-by-one bug in the trace output.
raskad
d8af7b4ee5