Unclear error message when incorrect typing was specified

[Joachim Jansen]

Attached is a file with the following error message:

Error: The arity of symbol SUCC:t is different from the arity of the table (2)assigned to it. At ...

The error is that SUCC[:t] requests the function SUCC that takes no arguments and maps to t, which indeed does not exist. But it is quite difficult to see this from the message.

[Joachim Jansen]

Wat zou dan de correcte formulering zijn van de bijgevoegde modellering?

[Broes De Cat]

SUCC[t:t]