Parse box keyword in patterns below top-level

[ecstatic-morse]

This extends the parser to handle patterns like if let Some(box x) = ... where the box keyword is not at the top-level. The last line of the added test caused a ParseError. This is a variant of #1412 which was not fixed by #1414.

I'm not familiar with rust-analyzer, otherwise I would fix this as well 😄.

[matklad]

Looks like BOX_KW is missing from PATTERN_FIRST

[ecstatic-morse]

@matklad This does indeed fix the problem. Is there a way to bless parser test output?

[matklad]

THhere's a magical REWRITE constant somehwere

[matklad]

bors r+

Thanks!

[bors]

Build failed

• continuous-integration/travis-ci/push

[ecstatic-morse]

Oops, forgot to include the changes to the inline test as well. Should be ready to go once travis is green.

[matklad]

bors r+

No need to wait for travis when we have bors!

[bors]

Build succeeded

• continuous-integration/travis-ci/push

[ecstatic-morse]

Ugh, apparently this doesn't fix cases where a box pattern appears in conjunction with a struct or enum pattern like Some(box Struct { field: 0 }).

[matklad]

Hm, yeah, box at the moment is parsed as a BindPat, that is, stuff like ref mut x. But it obviously should be a completely separate pat kind, as rhs is not restricted to an identifier. To fix this, you'll need to add PAT_BOX to grammar.ron's nodes secion, PatBox to ast section, and to Pat variants. The ast types can be regenrated by cargo gen-syntax. Than the parsing of patterns should be fixed.

[ecstatic-morse]

Okay, I'll look into this. It might take longer than an hour though 😃