{"ast_node_type":"variable","tokens":[{"end":57,"kind":"keyword","start":0,"text":"let"}]}
        let ret_ty = ret_coercion.borrow().expected_ty();
        let closure_span = self.tcx.def_span(body_def_id);
        let ret_ty = self.try_structurally_resolve_type(closure_span, ret_ty);