{"ast_node_type":"variable","tokens":[{"end":56,"kind":"keyword","start":0,"text":"let"}]}
        let const_ = self.monomorphize(constant.const_);
    fn eval_constant(&mut self, constant: &mir::ConstOperand<'tcx>) -> Option<mir::ConstValue> {
        // Evaluate the constant. This makes const eval failure a collection-time error (rather than