enum System.Reflection.GenericParameterAttributes flags:

   def enum
      None = 0
      Covariant = 1
      Contravariant = 2
      VarianceMask = 3
      ReferenceTypeConstraint = 4
      NotNullableValueTypeConstraint = 8
      DefaultConstructorConstraint = 16
      SpecialConstraintMask = 28.

end enum.
