Original bug ID: 5939
Reporter: @alainfrisch
Assigned to: @damiendoligez
Status: closed (set by @xavierleroy on 2016-12-07T10:34:20Z)
Resolution: fixed
Priority: normal
Severity: minor
Target version: 4.02.0+dev
Fixed in version: 4.02.0+dev
Category: ~DO NOT USE (was: OCaml general)
Related to: #5936

Bug description

I found the following when trying to clean up the Parsetree by putting Pexp_when clauses where they belong in the AST:

fun (type t) when false -> 0;;

Fatal error: exit(0) outside appropriated catch
Fatal error: exception Misc.Fatal_error

The fix is not difficult (either in the parser or in the type-checker). But I'm wondering whether it make sense to keep the syntax:

fun pat when cond -> ...

which necessarily triggers warning 25 (bad style, all clauses in this pattern-matching are guarded).

The Parsetree cleanup would be a little bit simpler if we got rid of this form as well. I doubt anyone uses it. I propose to get rid of it, after (i) asking on the caml-list if anyone objects; (ii) using OPAM to check that the construction is indeed not used in any of the packaged software.