Higher-order generic functions disobey kind system

[brson]

fn spawn2<@T>(x: T, f: fn(T))  {
    f(x);
}

fn main() {
    fn foo<~T>(x: T) {
        log_err x;
    }

    spawn2::<@int>(@10, foo);
}

spawn2 is passing a shared kind to a function that only takes unique kinds.

[brson]

There are probably similar issues with other generic types.

[marijnh]

The restriction on taking the value of generics is currently making this impossible to reproduce.

But even ignoring that, and updating the example to the new terminology, the current kind checker would catch that foo is being instantiated with a type that it doesn't accept. Closing (by #1177)