Implicit facts with multirelations

Questions
1

Hi, I have a question about the associativity of the arrow operator when generating implicit facts associated with multi-relations:

sig A {}
sig B {}
sig C {}
sig X {
f : one A
}
sig Y {
g : A -> B -> C
}

When creating the implicit fact for X, f is interpreted as X set -> one A. The arrow operator is left-associative, so A->B->C is interpreted as ((A->B)->C). When creating the implicit fact for Y, is g interpreted as Y set -> set ((A->B)->C), or (((Y set -> set A)->B)->C), or some other way?