# E0046

Warning name: `unused_rest_mark`

Useless `..` in struct or constructor pattern.

`..` can be used to ignore unmatched fields in struct pattern, or ignore
unmatched labelled arguments in constructor pattern. But if all fields/labelled
arguments are already matched, the `..` is useless, and this warning will be
emitted.

## Erroneous example

```{literalinclude} /sources/error_codes/0046_error/top.mbt
:language: moonbit
```