# Motive::not-a-type


**Key:** `Motive::not-a-type`

**Category:** sort · **Severity:** error

**Source:** [`src/diag/hints.nix:894`](https://github.com/kleisli-io/nix-effects/blob/main/src/diag/hints.nix#L894)

an eliminator's motive must return a type (live in some U(k))

## Example

`Hint::Motive::not-a-type` means the `Motive` position uses a term or value where the checker needs a type. The example shows the failing form first, then one way to give the checker the missing structure.

```nix
# Bad: the motive returns a term.
motive = x: natLit 0

# Better: the motive returns a type.
motive = x: nat

```


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