PROTO_UV_IMMUTABLE  144 lj_func.c          uv->immutable = ((v / PROTO_UV_IMMUTABLE) & 1);
PROTO_UV_IMMUTABLE  170 lj_func.c            uv->immutable = ((v / PROTO_UV_IMMUTABLE) & 1);
PROTO_UV_IMMUTABLE 1330 lj_parse.c           uv[i] = vstack[vidx].slot | PROTO_UV_LOCAL | PROTO_UV_IMMUTABLE;