{"ast_node_type":"other","tokens":[{"end":68,"kind":"keyword","start":0,"text":".map_err(|e|"}]}
            .map_err(|e| MirEvalError::LayoutError(e, ty.clone()))?;
            .layout_of_ty(ty.clone(), self.trait_env.clone())
        self.layout_cache.borrow_mut().insert(ty.clone(), r.clone());