Reports type variables whose variance (in, out, or unchecked) conflicts with another declaration. Type variables must match in variance between partial declarations of the same class or module, even if the type variables have different names.

Example:

# Type variable 'B' of class 'Example' has a variance which conflicts with other declarations, ...
class Example[A, in B, out C]
end

# Type variable 'Y' of class 'Example' has a variance which conflicts with other declarations, ...
class Example[X, Y, Z]
end