E0052: Token missing mint fn

A token definition must declare at least one mint fn. Without one, the token can never be created, so it would be useless.

Example (error)

token MyToken {
    impl Token {
        fn attach(to: Utxo) {}
        fn detach(source: Utxo) {}
    }
}

Fix

Add at least one mint fn:

token MyToken {
    mint fn mint() {}
    impl Token {
        fn attach(to: Utxo) {}
        fn detach(source: Utxo) {}
    }
}