Add a .messages file for Menhir

[DemiMarie]

I think we can all agree that better syntax error messages would be nice.

[let-def]

I am working on improving error messages. It is a research project, I cannot tell exactly when it will be ready, but the situation should be better in a few months from now.

My solution is not directly based on .messages but could be seen as a generalization.

[github-actions]

This issue has been open one year with no activity. Consequently, it is being marked with the "stale" label. What this means is that the issue will be automatically closed in 30 days unless more comments are added or the "stale" label is removed. Comments that provide new information on the issue are especially welcome: is it still reproducible? did it appear in other contexts? how critical is it? etc.

[DemiMarie]

Still open unless @let-def has changed something.

[let-def]

I confirm that I am still working on that topic (though this is not my main project and needs a lot more work)

[github-actions]

This issue has been open one year with no activity. Consequently, it is being marked with the "stale" label. What this means is that the issue will be automatically closed in 30 days unless more comments are added or the "stale" label is removed. Comments that provide new information on the issue are especially welcome: is it still reproducible? did it appear in other contexts? how critical is it? etc.

[DemiMarie]

Still an issue. @let-def any updates?

[gasche]

I can provide an update from my (imperfect) understanding: @let-def has indeed managed to finish a first prototype of an improved approach to error messages (I would hazard the guess that the result is in the lrgrep repository). But currently there is no active work on upstreaming support for OCaml error messages. I hope that @let-def or people using his work will actually try to upstream something, but probably not before a few months.

[lpw25]

@let-def has been working on upstreaming lrgrep into merlin first, which is a slightly easier place to experiment with things. We're in the process of getting set up to try this prototype out inside Jane Street.