Identifier limitation

The following code is accepted:

let main (p_,s: unit * int): operation list * int =
    [], s

The following code is accepted:

let main (_p,s: unit * int): operation list * int =
    [], s

The following code is rejected:

let main (_p_,s: unit * int): operation list * int =
    [], s

Variable named _something_ is refused

Error: File "/tmp/tmp-1ZsLVwaVMl72P.mligo", line 1, characters 12-13:
  1 | let main (_p_,s: unit * int): operation list * int =
  2 |     [], s
Ill-formed pattern.
At this point, one of the following is expected:
  * a closing parenthesis ')', if the pattern is complete;
  * a comma ',' followed by another component as a pattern, if
    defining a tuple pattern;
  * a type annotation starting with ':'.```

Compiler version: 2022-12-02T18:37:36+00:00 Commit Commit Date: Rolling SHA: b61d0f82 release