Stack traces in refmt are masked.

[jordwalke]

There's a main try block in refmt_impl.ml that does the following:

  with
  | exn ->
    Location.report_exception Format.err_formatter exn;
    exit 1

``

That is apparently masking our stack traces. I don't know what it's supposed to do or how to prevent it from masking stack traces.

[bobzhang]

this may be useful:

external reraise : exn -> 'a = "%reraise"

it will keep stacktrace

[jordwalke]

Thank you, Bob!

[jordwalke]

(lowpri) To refine this github issue: I think we want to reraise the exception if it's not a parse error, but do what we currently do if it is a parse error.