Closure type expectations do not guide type inference?

```rust
fn foo(i: isize) -> isize { i + 1 }

fn apply<A, F>(f: F, v: A) -> A where F: FnOnce(A) -> A { f(v) }

pub fn main() {
    let f = |i| foo(i);
    assert_eq!(apply(f, 2), 3);
}
```

`apply(f, 2)` is not constraining the type of `2` or `3` to be `isize`, which causes the obligations registered by `apply` to fail after fallback!