Nicholas Nethercote f8edc831ca Pretty-print PatKind::Missing as _.
Printing "no pattern" as `_` isn't ideal, but better than crashing, and
HIR pretty-printing already has plenty of imperfections. The added `f2`
and `f6` examples are ones that triggered the crash.

Note that some of the added examples are printed badly, e.g.
`fn(, ...)`. The next commit will fix those.

Fixes #139633.
2025-04-15 10:40:58 +10:00
..