Welcome in the forum, MyLord ;-)
This bug is well known and has to do with the on-line checker named "Clang" which is active while you are typing.
Insert some blank lines at the end of your file and the assertion will go away.
I assume this is the clang.dll bug. I added some blank lines around the end of the file and it appears to be okay now.
Thnaks for the self diagnosis and feedback My Lord.