# E3801

Compiler diagnostic name: `inclusive_range_pattern_missing_equal`.

Range pattern is missing `=`.

Range patterns must spell out whether the upper bound is inclusive or exclusive.
Use `a..=b` for an inclusive range and `a..<b` for an exclusive range.

## Erroneous example

```{literalinclude} /sources/error_codes/3801_error/top.mbt
:language: moonbit
```

`1..2` is not accepted as a pattern because it does not say whether `2` is
included.

## Suggestion

Choose an inclusive or exclusive range pattern explicitly.

```{literalinclude} /sources/error_codes/3801_fixed/top.mbt
:language: moonbit
```