The compiler this script was imported with is not available anymore

I’m having this issue for a few hours for now. I am trying to guess what is going wrong but it is hard to because I don’t know what is the problematic script.

Any ideas?

I have found why: I did not named the C# file like the MonoBehaviour class that was inside of it. So when the object of this class was instantiated and I updated me script while playing the editor, this error occured.