# XO0164: `(`, `[`, or `{` not closed before end of file

The file ended while a delimiter was still open. The diagnostic points at the opening delimiter and notes where the file ended. The prototype reports this for an unclosed `{`; an unclosed `(` or `[` currently surfaces as XO0160 at the token that cannot continue the list. See core 15.

## Example

```xo
fn f() -> Int {
  1
```

## Fix

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

Run `xo explain XO0164` for this text in a terminal, or see
[section 10.6 of the specification](../../spec/core/#106-diagnostic-codes).