# E0071

Warning name: `core_package_not_imported`

Core package used without an explicit import.

MoonBit still recognizes some packages under `moonbitlang/core` when they are
referenced by their conventional aliases, but relying on that implicit import is
deprecated. Add the package to `moon.pkg` instead.

## Erroneous example

```{literalinclude} /sources/error_codes/0071_error/top.mbt
:language: moonbit
```

## Suggestion

Declare the core package import in `moon.pkg`.

```{literalinclude} /sources/error_codes/0071_fixed/moon.pkg
:language: moonbit
```

```{literalinclude} /sources/error_codes/0071_fixed/top.mbt
:language: moonbit
```