Auto merge of #79070 - jonas-schievink:rollup-wacn2b8, r=jonas-schievink

Rollup of 13 pull requests

Successful merges:

 - #77802 (Allow making `RUSTC_BOOTSTRAP` conditional on the crate name)
 - #79004 (Add `--color` support to bootstrap)
 - #79005 (cleanup: Remove `ParseSess::injected_crate_name`)
 - #79016 (Make `_` an expression, to discard values in destructuring assignments)
 - #79019 (astconv: extract closures into a separate trait)
 - #79026 (Implement BTreeMap::retain and BTreeSet::retain)
 - #79031 (Validate that locals have a corresponding `LocalDecl`)
 - #79034 (rustc_resolve: Make `macro_rules` scope chain compression lazy)
 - #79036 (Move Steal to rustc_data_structures.)
 - #79041 (Rename clean::{ItemEnum -> ItemKind}, clean::Item::{inner -> kind})
 - #79058 (Move likely/unlikely argument outside of invisible unsafe block)
 - #79059 (Print 'checking cranelift artifacts' to easily separate it from other artifacts)
 - #79063 (Update rustfmt to v1.4.26)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

1 files changed, 3 insertions, 0 deletions

diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index 188bf227c42..ffbf786491d 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -1089,6 +1089,9 @@ impl<'a> Parser<'a> {
             self.parse_yield_expr(attrs)
         } else if self.eat_keyword(kw::Let) {
             self.parse_let_expr(attrs)
+        } else if self.eat_keyword(kw::Underscore) {
+            self.sess.gated_spans.gate(sym::destructuring_assignment, self.prev_token.span);
+            Ok(self.mk_expr(self.prev_token.span, ExprKind::Underscore, attrs))
         } else if !self.unclosed_delims.is_empty() && self.check(&token::Semi) {
             // Don't complain about bare semicolons after unclosed braces
             // recovery in order to keep the error count down. Fixing the