# XO0150: character that cannot start any token

The lexer found a character that begins no Xo token, such as `@` or a stray Unicode symbol outside a string or comment. Xo source is UTF-8 and identifiers are `[A-Za-z_][A-Za-z0-9_]*`. Remove the character or move it into a string literal. See core 1.1 and 1.5.

## Example

```xo
fn f(x: Int) -> Int {
  x @
}
```

## Fix

```xo
fn f(x: Int) -> Int {
  x
}
```

Run `xo explain XO0150` for this text in a terminal, or see
[section 10.6 of the specification](../../spec/core/#106-diagnostic-codes).