"unable to find implementation of trait" with a combination of a generic trait & a static method

[brendanzab]

struct Foo<T>(T);

impl<T> Foo<T> {
    static pure fn foo<U>(theta: U) -> Foo<T> {
        Bar::bar(theta)
    }
}

impl<T> Foo<T>: Bar<T> {
    static pure fn bar<U>(_theta: U) -> Foo<T> { fail(~"") }
}

trait Bar<T> {
    static pure fn bar<U>(theta: U) -> self;
}

fn main() {}

$ rustc cross_mod_traits.rs
test.rs:5:8: 5:16 error: failed to find an implementation of trait @Bar<<V1>> for <V2>
test.rs:5         Bar::bar(theta)

When I remove the type parameters on any of the items it compiles.

[brendanzab]

@catamorphism (nag nag)

[graydon]

reproduced on 2013-03-25

[graydon]

non-critical for 0.6, de-milestoning

[metajack]

Still reproducible. Here's the updated example:

struct Foo<T>(T);

impl<T> Foo<T> {
    fn foo<U>(theta: U) -> Foo<T> {
        Bar::bar(theta)
    }
}

impl<T> Bar<T> for Foo<T> {
    fn bar<U>(_theta: U) -> Foo<T> { fail!(~"") }
}

trait Bar<T> {
    fn bar<U>(theta: U) -> Self;
}

fn main() {}

I'm not sure how important this is. Nominating for production ready.

[graydon]

accepted for production-ready milestone

[graydon]

see also #5527, this is somewhat of a sub-bug or case to define.

[emberian]

Still reproducible.

[msullivan]

OK, this seems fixed.

[emberian]

@msullivan is there a test case?