Change order of copy and borrow to avoid conflict

Note that the first argument is `self as &mut dyn Delegate`, so this
isn't allowed with two-phase borrows.

Author: matthewjasper

src/librustc_passes/rvalue_promotion.rs

@@ -248,7 +248,8 @@ impl<'a, 'tcx> CheckCrateVisitor<'a, 'tcx> {
         let tcx = self.tcx;
         let param_env = self.param_env;
         let region_scope_tree = self.tcx.region_scope_tree(item_def_id);
-        euv::ExprUseVisitor::new(self, tcx, param_env, &region_scope_tree, self.tables, None)
+        let tables = self.tables;
+        euv::ExprUseVisitor::new(self, tcx, param_env, &region_scope_tree, tables, None)
             .consume_body(body);
 
         let body_promotable = self.check_expr(&body.value);