Bad type inference error message with unboxed closures

[carllerche]

Given the following code:

#![feature(unboxed_closures)]
#![feature(overloaded_calls)]

fn action<T: Send, F: FnOnce<(T,), ()> + Send>(v: T, f: F) {
    f(v);
}

pub fn main() {
    let (tx, rx) = channel();

    action("zomg", move |:v| tx.send(v));
    rx.recv();
}

I get the error message:

fnonce.rs:11:5: 11:11 error: unable to infer enough type information to locate the impl of the trait `core::kinds::Send` for the type `closure`; type annotations required
fnonce.rs:11     action("zomg", move |:v| tx.send(v));
                 ^~~~~~
fnonce.rs:11:5: 11:11 note: the trait `core::kinds::Send` must be implemented because it is required by `action`
fnonce.rs:11     action("zomg", move |:v| tx.send(v));
                 ^~~~~~

This error message was quite confusing and the actual error was caused by the type inferencer not being able to figure out the type of channel(). If I change that bit to: channel::<&'static str>(), everything compiles fine.

[carllerche]

This appears to be fixed. New code snippet is:

use std::sync::mpsc::*;

fn action<T: Send, F: FnOnce(T) + Send>(v: T, f: F) {
    f(v);
}

pub fn main() {
    let (tx, rx) = channel();

    action("zomg", move |v| { tx.send(v); });
    rx.recv();
}