Merge #1722

1722: Parse `box` keyword in patterns below top-level r=matklad a=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 :smile:.~~

Co-authored-by: Dylan MacKenzie <[email protected]>

2 files changed, 3 insertions, 1 deletions

diff --git a/crates/ra_parser/src/grammar/expressions/atom.rs b/crates/ra_parser/src/grammar/expressions/atom.rs
index bc942ae01..ab8fb9f6e 100644
--- a/crates/ra_parser/src/grammar/expressions/atom.rs
+++ b/crates/ra_parser/src/grammar/expressions/atom.rs
@@ -414,6 +414,8 @@ pub(crate) fn match_arm_list(p: &mut Parser) {
 //         X | Y if Z => (),
 //         | X | Y if Z => (),
 //         | X => (),
+//         box X => (),
+//         Some(box X) => (),
 //     };
 // }
 fn match_arm(p: &mut Parser) -> BlockLike {
diff --git a/crates/ra_parser/src/grammar/patterns.rs b/crates/ra_parser/src/grammar/patterns.rs
index df6000707..1f6a6fd48 100644
--- a/crates/ra_parser/src/grammar/patterns.rs
+++ b/crates/ra_parser/src/grammar/patterns.rs
@@ -2,7 +2,7 @@ use super::*;
 
 pub(super) const PATTERN_FIRST: TokenSet = expressions::LITERAL_FIRST
     .union(paths::PATH_FIRST)
-    .union(token_set![REF_KW, MUT_KW, L_PAREN, L_BRACK, AMP, UNDERSCORE, MINUS]);
+    .union(token_set![BOX_KW, REF_KW, MUT_KW, L_PAREN, L_BRACK, AMP, UNDERSCORE, MINUS]);
 
 pub(super) fn pattern(p: &mut Parser) {
     pattern_r(p, PAT_RECOVERY_SET);