Fix manual_option_as_slice for ref bindings

Author: cuishuang

clippy_lints/src/manual_option_as_slice.rs

@@ -67,9 +67,9 @@ impl LateLintPass<'_> for ManualOptionAsSlice {
             },
             ExprKind::If(cond, then, Some(other)) => {
                 if let ExprKind::Let(let_expr) = cond.kind
+                    && is_empty_slice(cx, other.peel_blocks())
                     && let Some(binding) = extract_ident_from_some_pat(cx, let_expr.pat)
                     && check_some_body(cx, binding, then)
-                    && is_empty_slice(cx, other.peel_blocks())
                 {
                     check_as_ref(cx, let_expr.init, span, self.msrv);
                 }