# E4044

Struct fields are missing. Use `..` to ignore them in patterns.

## Erroneous Example

```moonbit
struct S { a : Int; b: Int }
let a : Int = match S::{ a: 2, b: 3 } {
  { a: 2 } => 4
  _ => 6
}
```

The example above tries to match a struct with a missing field `b`,
giving the following error on line 3:

```
Struct fields b are unmatched, use `..` to ignore them.
```

## Suggestion

Make sure to provide all fields in the pattern,
or simply ignore the missing fields using `..`:

```{literalinclude} /sources/error_codes/E4044_fixed/top.mbt
:language: moonbit
```