alt/base_prot_sig2_alt4.nit:24,23--32: Error: The protected property `vproA` cannot contain the type `A` from the private module `base_prot_sig`
alt/base_prot_sig2_alt4.nit:24,23--32: Error: The protected property `vproA=` cannot contain the type `A` from the private module `base_prot_sig`