// Not sure which of the two versions of this method give better performance -- you might want to test yourself.
public static IEnumerable <Type> DerivedTypesFromAllAssemblies(this Type baseType)
{
// TODO: Optimization: check if baseType is private or internal.
var assemblies = AssemblyExtensions.GetAllAssemblies();
Debug.Assert(assemblies.Count() == assemblies.Distinct().Count());
return(assemblies
.SelectMany(a => a.GetTypes())
.Where(t => baseType.IsAssignableFrom(t)));
}
