Constraining Generics to be not applied with function or closure

Using Swift
1

I'm looking for a solution to avoid this:

func gen<T>(value: T) {
    ...
}
gen(value: { ... })
or
gen(value: { (a: Int) in ... }
...

We can constrain T to conform to some Protocoles or to be of some types or Any or AnyObject...
We can also check that T is of some Types or AnyObject at the func 1st stage.

But I didn't find any way to say: !Function or !Closure

Any ideas?

2

I think we need some more detail: why are you trying to prevent this?

3

It's only for academic reasons, to know if it's possible.

4

In Swift as it exists today, it is not possible.

5

Ok. Thanks.