I have found the reason for the misbehavior:

Editor and NoEditor are defined in (editor interfaces elements), whereas
WithCursor is defined in (editor interfaces painting).

The (editor interfaces painting) is imported as a dependency by (editor
interfaces elements). The test imported both modules, but it imported
(editor interfaces elements) before its dependency.

Swapping the order of imports resolved the issue.

czw., 4 sty 2024, 07:59 użytkownik Panicz Maciej Godek <
godek.maciek@gmail.com> napisał:

> Thanks for explanation.
> But if the Editor interface extends WithCursor interface, and NoEditor
> implements Editor interface, doesn't it imply that it implements WithCursor
> interface?
>
> czw., 4 sty 2024, 02:19 użytkownik Per Bothner <per@bothner.com> napisał:
>
>> On 1/3/24 15:33, Panicz Maciej Godek via Kawa wrote:
>> > The thing is, that all the required methods from the interface
>> WithCursor
>> > are implemented by NoEditor.
>> >
>> > But I wonder why Kawa claims that the interface isn't implemented when
>> > clearly all the required methods are present.
>>
>> Kawa, like Java, requires an interface to be *explicitly* implemented by
>> a class.
>> It is not enough to implement all the methods of the interface.
>> --
>>         --Per Bothner
>> per@bothner.com   http://per.bothner.com/
>>
>