Consider this.pyi code snippet:

fromtypingimportAny,Generic,Self,TypeVar,TypeVarTuple,type_check_onlyT=TypeVar("T")Ts=TypeVarTuple("Ts")@type_check_onlyclassS(tuple[*Ts],Generic[T,*Ts]):deff(self,x:T,/)->T: ...

When ran throughmypy (checked with1.15.0 and the master branch), the following error is reported

Argument 1 to "type_check_only" has incompatible type "type[S[T, *Ts]]"; expected "type[S[T, *Ts]]"  [arg-type]

mypy playground repro

Without the additionalT type parameter, the false positive error disappears. It also disappears if I remove thetuple baseclass.
And as far as I could tell, it doesn't seem to be associated with a particular config option or cli flag.