# E4040

The type constructor expects a different number of arguments than provided.

## Erroneous Example

```{literalinclude} /sources/error_codes/4040_error/top.mbt
:language: moonbit
```

The example above tries to create an instance of the `Option` type.
The `Option` type is a generic type that expects a single type argument,
but the example does not provide any type arguments,
giving the following error on line 1:

```
The type constructor Option expects 1 argument(s), but is here given 0 argument(s).
```

## Suggestion

Make sure to provide the correct number of type arguments:

```{literalinclude} /sources/error_codes/4040_fixed/top.mbt
:language: moonbit
```