refactor path pattern checking to get info for peeling

See the doc comment on `ResolvedPat` for more information. This and the
next couple commits split resolution apart from checking for path,
struct, and tuple struct patterns, in order to find the pattern's type
before peeling the scrutinee. This helps us avoid peeling the scrutinee
when the pattern could match it.

The reason this handles errors from resolution after peeling is for
struct and tuple struct patterns: we check their subpatterns even when
they fail to resolve, to potentially catch more resolution errors. By
doing this after peeling, we're able to use the updated `PatInfo`. I
don't know if there's currently any observable difference from using the
outdated `PatInfo`, but it could potentially be a source of subtle
diagnostic bugs in the future, so I'm opting to peel first.

0 files changed, 0 insertions, 0 deletions