pub type AliasExpander<'a> = &'a dyn Fn(&Type) -> Type;Expand description
One-level expander for recursion back-edges. Given a Type::AliasRef, returns
the alias body (peeled, args substituted); for any other type returns ty.peel()
cloned. Lets the union resolver classify a recursive member by its underlying
JSON kind without the resolver itself owning the type namespace.