{"ast_node_type":"variable","tokens":[{"end":93,"kind":"keyword","start":0,"text":"let"}]}
                                let ty = &field_types[f].clone().substitute(Interner, subst);
                                    l.fields.offset(u32::from(f.into_raw()) as usize).bytes_usize();
                                let size = this.layout(ty)?.size.bytes_usize();