invalid_internal_annotation

Only public elements in a package's private API can be annotated as being internal.

The analyzer produces this diagnostic when a declaration is annotated with the internal annotation and that declaration is either in a public library or has a private name.

The following code, when in a public library, produces this diagnostic because the internal annotation can't be applied to declarations in a public library:

import 'package:meta/meta.dart';
​
@internal
class C {}

The following code, whether in a public or internal library, produces this diagnostic because the internal annotation can't be applied to declarations with private names:

import 'package:meta/meta.dart';
​
@internal
class _C {}
​
void f(_C c) {}

If the declaration has a private name, then remove the annotation:

class _C {}
​
void f(_C c) {}

If the declaration has a public name and is intended to be internal to the package, then move the annotated declaration into an internal library (in other words, a library inside the src directory).

Otherwise, remove the use of the annotation:

class C {}