implementation_imports

Import of a library in the 'lib/src' directory of another package.

The analyzer produces this diagnostic when an import references a library that's inside the lib/src directory of a different package, which violates the convention for pub packages.

The following code, assuming that it isn't part of the ffi package, produces this diagnostic because the library being imported is inside the top-level src directory:

import 'package:ffi/src/allocation.dart';

If the library being imported contains code that's part of the public API, then import the public library that exports the public API:

import 'package:ffi/ffi.dart';

If the library being imported isn't part of the public API of the package, then either find a different way to accomplish your goal, assuming that it's possible, or open an issue asking the package authors to make it part of the public API.