Formatting: rescript format delete comment on a record field

[cometkim]

running format on this code:

type a = {
  foo: string, /** here */
}

output:

type a = {foo: string}

the /** ... */ style comment is deleted on the formatting result. // ... style comments are fine.

[zth]

That's expected, because /** */ are docstrings, and they need to be attached to whatever it is they're documentation for. And here there's nothing to attach the comment to.

Either putting it before the field name (so it can be attached to the field name), or using a regular /* */ comment would work.

[cometkim]

um okay I wasn't aware that docstrings were treated specially.

Other users may feel the same way and can experience it being deleted. I think it makes for a less embarrassing experience when the parser throws a syntax error in the first place instead of dropping it later.

[cristianoc]

Actually, for doc comments the expectation is that it's either preserved or a syntax error.
So this looks like a bug.

[cristianoc]

OK looks like these two (no comma, or move to the other side of comma) are syntax errors:

 Syntax error!
  tst.res:2:14-25

  1 │ type a = {
  2 │   foo: string /** here */
  3 │ }

  Did you forget a `,` here?


  Syntax error!
  tst.res:2:14-25

  1 │ type a = {
  2 │   foo: string /** here */,
  3 │ }

  Did you forget a `,` here?

So likely a parsing issue.

[cristianoc]

What's going on is likely: the doc comments are expected to be at the beginning. So they're parsed ahead of time.
The } is encountered and the parser forgets of having parsed the doc comment.
So an error message should be emitted in that case.