Merge #1847

1847: Allow an underscore as the identifier in `const` items r=matklad a=ecstatic-morse

[RFC 2526](https://github.com/rust-lang/rust/issues/54912) was recently stabilized, meaning `const _: i32 = 5;` is now a valid item.

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

1 files changed, 10 insertions, 1 deletions

diff --git a/crates/ra_parser/src/grammar/items/consts.rs b/crates/ra_parser/src/grammar/items/consts.rs
index e11546333..63e0e6e0c 100644
--- a/crates/ra_parser/src/grammar/items/consts.rs
+++ b/crates/ra_parser/src/grammar/items/consts.rs
@@ -12,7 +12,16 @@ fn const_or_static(p: &mut Parser, m: Marker, kw: SyntaxKind, def: SyntaxKind) {
     assert!(p.at(kw));
     p.bump_any();
     p.eat(T![mut]); // FIXME: validator to forbid const mut
-    name(p);
+
+    // Allow `_` in place of an identifier in a `const`.
+    let is_const_underscore = kw == T![const] && p.eat(T![_]);
+    if !is_const_underscore {
+        name(p);
+    }
+
+    // test_err static_underscore
+    // static _: i32 = 5;
+
     types::ascription(p);
     if p.eat(T![=]) {
         expressions::expr(p);