rustdoc: Generates wrong signature for function with associated type parameter

[mbudde]

Create a library with the following src/lib.rs:

pub trait SomeTrait {
    type Typ;
}

pub struct Foo<T> {
    bar: T
}

impl<T: SomeTrait> Foo<T> {
    pub fn foo(&self, bar: T::Typ) {}
}

and run cargo doc. The documentation will show the type of Foo::foo as fn foo(&self, bar: T) and not fn foo(&self, bar: T::Typ) as expected.

rustdoc 1.0.0-beta (9854143cb 2015-04-02) (built 2015-04-02)

[steveklabnik]

You may want to try the nightly; a number of bugs have been fixed post-beta. Can you check?

[mbudde]

@steveklabnik: I can reproduce with rustdoc 1.0.0-nightly (e6a812402 2015-04-14) (built 2015-04-14).

[steveklabnik]

👍 thanks for checking.

[huonw]

triage: I-nominated

This can lead to some very confusing signatures, especially since associated types are quite widely used in the standard library with core types like iterators.

[mbudde]

I ran into the problem while reading the documentation for mio. I have not been able to find any instances of this problem in the standard library (only a couple of hits in the librustc crate) [1] .

[1] git grep '\<fn[^(]*([^)]*[A-RT-Z][a-zA-Z_]*::[A-Z][^)]*)'

[pnkfelix]

P-high, not 1.0. Seems nice to fix, but without an example of this bug occurring in the stdlib itself, it is not a 1.0 blocker.

[bluss]

The exception seems to be associated types on Self. Those display.

Libcore displays this problem! But libstd does not. See .zip() in libcore and .zip() in libstd