Whitespace in groups

[carl-wallace]

I was failing to validate a large CDDL file that looked like it ought work and distilled the issue down to this pattern:

$$A //= (b =>
   [+int])

The resulting error for the above was this:

error: parser errors
  ┌─ input:2:4
  │
2 │    [+int])
  │    ^ invalid group entry syntax

However, removing the new line clears the error.

$$A //= (b => [+int])

So does using a ":" instead of "=>". Additionally, when a colon is used, a newline does not cause an error.

$$A //= (b : [+int])

Or:

$$A //= (b : 
   [+int])

It looks to me that the issue is in whitespace handling where => is used. Adding the following at line 2606 in parser.rs fixes the issue for me. This is similar to whitespace handling for the colon case a few lines below 2606. I have not tested without the ast-comments feature enabled.

      #[cfg(feature = "ast-comments")]
          let _ = self.collect_comments()?;
      #[cfg(not(feature = "ast-comments"))]
      self.advance_newline()?;