Fatal error: Matching.comp_exit on `switch ... if`

[liweijian]

Hi, I got an fatal error :

>> Fatal error: Matching.comp_exit
Fatal error: exception Whole_compiler.Misc.Fatal_error
FAILED: cannot make progress due to previous errors.

With the minimal test case:

let is_digit = c => c >= '0' && c <= '9'

let head_char = c => switch c {
| '(' => Js.log("got lparen")
| ')' => Js.log("got rpare")
| c if is_digit(c) => Js.log("got num")
}

With VSCode information:

Just wondering if anything I'd missed?

[cristianoc]

Probably related: #5557