register_fn.md

Try 1: Constrain with FnRegister

pub fn register<T: FnRegister>(&mut self, f: T, name: &str) {
    f.register(self, name);
}

Error: the trait rhai::fn_register::FnRegister is not implemented for the type fn(i32) -> i32 {add} [E0277]

Try 2: Constrain with Fn/closure

pub fn register<T: Fn(U)->V, U, V>(&mut self, f: T, name: &str) {
    f.register(self, name);
}

Error: no method named register found for type T in the current scope