Warnings in Crypto.Pipe

The following warnings cause the testsuite to fail:

.../lib/modules/Crypto.pmod/Pipe.pike:33: Warning: An expression of type array(array | object | mixed) cannot be assigned to a variable of type array({ CipherState = object(implements Nettle.Cipher()->State) }).
.../lib/modules/Crypto.pmod/Pipe.pike:38: Warning: An expression of type array(object) cannot be assigned to a variable of type array({ CipherState = object(implements Nettle.Cipher()->State) }).