# E0080

Warning name: `regex_match_missing_before`

A `lexmatch` pattern can skip an input prefix, but the pattern does
not bind or explicitly ignore that prefix.

An unanchored regex searches forward from the start of the input. Add `^` when
the match must start at the beginning, or add `before=` to bind or ignore the
skipped prefix.

## Erroneous example

```{literalinclude} /sources/error_codes/0080_error/top.mbt
:language: moonbit
```

## Suggestion

Anchor the regex at the start, or make the skipped prefix explicit with
`before=prefix` or `before=_`.

```{literalinclude} /sources/error_codes/0080_fixed/top.mbt
:language: moonbit
```