Linker error with private default methods used in a reachable method

[alexcrichton]

// foo.rs
mod inner {
    pub trait Trait {
        fn f(&self) { f(); }
    }

    impl Trait for int {}

    fn f() {}
}

pub fn foo<T: inner::Trait>(t: T) {
    t.f();
}

// bar.rs
extern mod foo;

fn main() {
    foo::foo(1);
}

$ rustc --lib foo.rs && rustc bar.rs -L.
foo.rs:8:4: 8:13 warning: code is never used: `f`, #[warn(dead_code)] on by default
foo.rs:8     fn f() {}
             ^~~~~~~~~
error: linking with `cc` failed: exit code: 1
note: cc arguments: '-m64' '-L/Users/alex/code/rust/lib/rustc/x86_64-apple-darwin/lib' '-o' 'bar' 'ba
r.o' '-L.' '-L/Users/alex/.rust' '-L/Users/alex' '-L/Users/alex/code/rust/lib/rustc/x86_64-apple-darw
in/lib' '-lstd-04ff901e-0.9-pre' '-L/Users/alex/code/rust/lib/rustc/x86_64-apple-darwin/lib' '-lgreen
-3b3a1962-0.9-pre' '-L/Users/alex/code/rust/lib/rustc/x86_64-apple-darwin/lib' '-lrustuv-7945354c-0.9
-pre' '-L.' '-lfoo-d4ab21d1-0.0' '-lpthread' '-lpthread' '-lmorestack' '-Wl,-rpath,@loader_path/code/
rust/lib/rustc/x86_64-apple-darwin/lib' '-Wl,-rpath,@loader_path/.' '-Wl,-rpath,/Users/alex/code/rust
/lib/rustc/x86_64-apple-darwin/lib' '-Wl,-rpath,/Users/alex'
note: Undefined symbols for architecture x86_64:
  "inner::f::h43f55e4ef1329dc2ab2b267e3dc9c21bd52230ed306d9a8f6f7cb8ea5526a838as::v0.0", referenced f
rom:
      inner::Trait::f::hbd66fdcd540500244e27378cca1f28a6e912ee31306da03d825a85f9538b613fah::v0.0 in b
ar.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

error: aborting due to previous error
task 'rustc' failed at 'explicit failure', /Users/alex/code/rust2/src/libsyntax/diagnostic.rs:102
task '<main>' failed at 'explicit failure', /Users/alex/code/rust2/src/librustc/lib.rs:441

[alexcrichton]

Another possibly related case which needs fixing:

// foo.rs
use inner::Trait;

mod inner {
    pub struct Foo;
    pub trait Trait {
        fn f(&self);
    }

    impl Trait for Foo {
        fn f(&self) { }
    }
}

pub trait Outer {
    fn foo<T: Trait>(&self, t: T) { t.f(); }
}

impl Outer for int {}

pub fn foo<T: Outer>(t: T) {
    t.foo(inner::Foo);
}

// bar.rs
extern mod foo;

fn main() {
    foo::foo(1);
}