Address review comments

Author: aerooneqq

compiler/rustc_ast_lowering/src/delegation.rs

@@ -82,10 +82,7 @@ static ATTRIBUTES_ADDITIONS: &[AttributeAdditionInfo] = &[
         kind: AttributeAdditionKind::Inherit {
             factory: |span, original_attribute| {
                 let reason = match original_attribute {
-                    hir::Attribute::Parsed(AttributeKind::MustUse {
-                        span: _,
-                        reason: Some(reason),
-                    }) => Some(reason.clone()),
+                    hir::Attribute::Parsed(AttributeKind::MustUse { reason, .. }) => reason.clone(),
                     _ => None,
                 };