Hi,
the Exception must be raised.
function TClassHierarchyExplorer.GetAllSubClasses(
Clazz: TClass): TEnumerable<TClass>;
begin
if not FAllSubClasses.ContainsKey(Clazz) then
raise EClassNotRegistered.Create(Clazz);
Result := FAllSubClasses[Clazz];
end;
Thanks for reporting. Fix will be included in next version.