{"ast_node_type":"variable","tokens":[{"end":52,"kind":"keyword","start":0,"text":"let"}]}
                let val = self.read_immediate(src)?;
            (ty::Dynamic(data_a, _, ty::Dyn), ty::Dynamic(data_b, _, ty::Dyn)) => {
                // MIR building generates odd NOP casts, prevent them from causing unexpected trouble.