# XO0179: retired: `var` with a tuple or list pattern

XO0179 reported `var` followed by a pattern, which only `let` took then, with a fix that wrote `let`. Decision 0384 (the owner, 2026-10-26) made `var PATTERN = e` bind every name of an irrefutable pattern as a `var` (core 3.1, 3.5), so the error is gone. The code stays reserved.

## Example

```xo
fn f() -> (Int, Int) { (1, 2) }

fn main(os: Os) {
  var (a, b) = f()
  a += b
  os.stdio.println("${a}")
}
```

## Fix

```xo
// no change needed: a and b are var
```

Run `xo explain XO0179` for this text in a terminal, or see
[section 10.6 of the specification](../../spec/core/#106-diagnostic-codes).