Type inference failure around closure argument types

[nikomatsakis]

This gist from jesse99 suggests a type inference failure:

https://gist.github.com/3795931

you have to add an explicit annot on the argument type to get it to work. this should not be necessary since the local variable was annotated. not sure what's going on here!

[nikomatsakis]

import comm::Chan;

type RingBuffer = ~[float];
type SamplesFn = fn~ (samples: &RingBuffer);

enum Msg
{
    GetSamples(~str, SamplesFn), // sample set name, callback which receives samples
}

fn foo(name: ~str, samples_chan: Chan<Msg>) {
    do task::spawn
    |copy name|
    {
        let callback: SamplesFn =
            |buffer|
            {
                for buffer.len().timesi |i| {error!("%?: %f", i, buffer[i])}
            };
        samples_chan.send(GetSamples(copy name, callback));
    };
}

fn main() {}

yields

/Users/nmatsakis/tmp/foo.rs:15:32: 19:13 error: mismatched types: expected `SamplesFn` but found `fn~(&RingBuffer)` (lifetime mismatch)
/Users/nmatsakis/tmp/foo.rs:15         let callback: SamplesFn =
/Users/nmatsakis/tmp/foo.rs:16             |buffer|
/Users/nmatsakis/tmp/foo.rs:17             {
/Users/nmatsakis/tmp/foo.rs:18                 for buffer.len().timesi |i| {error!("%?: %f", i, buffer[i])}
/Users/nmatsakis/tmp/foo.rs:19             };
note: the static lifetime...
note: ...does not necessarily outlive lifetime re_bound(br_anon(0))
error: aborting due to previous error

[catamorphism]

This seems to have been fixed. I'll check in a test case.