Auto merge of #53815 - F001:if-let-guard, r=petrochenkov

refactor match guard

This is the first step to implement RFC 2294: if-let-guard. Tracking issue: https://github.com/rust-lang/rust/issues/51114

The second step should be introducing another variant `IfLet` in the Guard enum. I separated them into 2 PRs for the convenience of reviewers.

r? @petrochenkov

1 files changed, 4 insertions, 1 deletions

diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index 95d5fba9668..0f6a9742309 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -2701,7 +2701,10 @@ impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
         // This has to happen *after* we determine which pat_idents are variants
         self.check_consistent_bindings(&arm.pats);
 
-        walk_list!(self, visit_expr, &arm.guard);
+        match arm.guard {
+            Some(ast::Guard::If(ref expr)) => self.visit_expr(expr),
+            _ => {}
+        }
         self.visit_expr(&arm.body);
 
         self.ribs[ValueNS].pop();