# E4138

Range operators only support builtin integer types, they cannot be used on this
type.

## Erroneous example

For example, you cannot use `Float` nor `Double` with range operators.

```{literalinclude} /sources/error_codes/4138_error/top.mbt
:language: moonbit
```

## Suggestion

Use integer types for the range operators, and generate floats from these
integers instead:

```{literalinclude} /sources/error_codes/4138_fixed/top.mbt
:language: moonbit
```

You can also use `until` to construct a range of numbers:

```{literalinclude} /sources/error_codes/4138_fixed/top_1.mbt
:language: moonbit
```