# DArgSort::universe-mismatch


**Key:** `DArgSort::universe-mismatch`

**Category:** universe · **Severity:** error

**Source:** [`src/diag/hints.nix:844`](https://github.com/kleisli-io/nix-effects/blob/main/src/diag/hints.nix#L844)

the sort position of `arg` must live in U(0); descriptions only carry small types. Pass `u 0`, or factor the dependency through `descRec` / `descPi` if a larger type is genuinely needed.

## Example

`Hint::DArgSort::universe-mismatch` means the `DArgSort` position uses a universe level that is too large for that slot. The example shows the failing form first, then one way to give the checker the missing structure.

```nix
# Bad: description argument sorts must stay in U0.
descArg (u 1) (_: descRet tt)

# Better: keep the argument sort small.
descArg (u 0) (_: descRet tt)

```


---

[← All diagnostic hints](/nix-effects/diag-hints)