1. Check all members of class clazz for overriding conditions. That is for overriding member M and overridden member O:

1.1. M must have the same or stronger access privileges as O. 1.2. O must not be final. 1.3. O is deferred, or M has override modifier. 1.4. If O is stable, then so is M. // @M: LIFTED 1.5. Neither M nor O are a parameterized type alias 1.6. If O is a type alias, then M is an alias of O. 1.7. If O is an abstract type then 1.7.1 either M is an abstract type, and M's bounds are sharper than O's bounds. or M is a type alias or class which conforms to O's bounds. 1.7.2 higher-order type arguments must respect bounds on higher-order type parameters -- @M (explicit bounds and those implied by variance annotations) -- @see checkKindBounds 1.8. If O and M are values, then 1.8.1 M's type is a subtype of O's type, or 1.8.2 M is of type []S, O is of type ()T and S <: T, or 1.8.3 M is of type ()S, O is of type []T and S <: T, or 1.9. If M is a macro def, O cannot be deferred unless there's a concrete method overriding O. 1.10. If M is not a macro def, O cannot be a macro def. 2. Check that only abstract classes have deferred members 3. Check that concrete classes do not have deferred definitions that are not implemented in a subclass. 4. Check that every member with an override modifier overrides some other member. TODO check that classes are not overridden TODO This still needs to be cleaned up; the current version is a staright port of what was there before, but it looks too complicated and method bodies are far too large.

Check that a class and its companion object to not both define a class or module with same name

Check that a deprecated val or def does not override a concrete, non-deprecated method. If it does, then deprecation is meaningless.

Only one overloaded alternative is allowed to define default arguments

Check that self type of this class conforms to self types of parents. and required classes.