A trait with a non-member function gives inconsistent and buggy results.

[paholg]

Rust version (this is on Arch):

$ rustc --version=verbose
rustc 0.13.0-nightly (b87619e27 2014-11-02 23:27:10 +0000)
binary: rustc
commit-hash: b87619e2744a64da38996c1a618dc28db746848b
commit-date: 2014-11-02 23:27:10 +0000
host: x86_64-unknown-linux-gnu
release: 0.13.0-nightly

This code

trait SomeTrait {
    fn fun();
}
struct A;
impl SomeTrait for A {
    fn fun() { println!("Hello!"); }
}
fn main() {
    let mut v: Vec<Box<SomeTrait>> = Vec::new();
    v.push(box A);
}

produces the following compiler panic:

$ cargo run --verbose
   Compiling test v0.0.1 (file:///home/paho/projects/test)
     Running `rustc /home/paho/projects/test/src/main.rs --crate-name test --crate-type bin -g --out-dir /home/paho/projects/test/target --dep-info /home/paho/projects/test/target/.fingerprint/test-7768c6b1caa470a0/dep-bin-test -L /home/paho/projects/test/target -L /home/paho/projects/test/target/deps`
error: internal compiler error: unexpected panic
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: http://doc.rust-lang.org/complement-bugreport.html
note: run with `RUST_BACKTRACE=1` for a backtrace
task 'rustc' panicked at 'assertion failed: *start <= *end', /home/rustbuild/src/rust-buildbot/slave/nightly-linux/build/src/libcore/slice.rs:421


Could not compile `test`.

Caused by:
  Process didn't exit successfully: `rustc /home/paho/projects/test/src/main.rs --crate-name test --crate-type bin -g --out-dir /home/paho/projects/test/target --dep-info /home/paho/projects/test/target/.fingerprint/test-7768c6b1caa470a0/dep-bin-test -L /home/paho/projects/test/target -L /home/paho/projects/test/target/deps` (status=101)
FAIL: 101

In addition, trying to call A::fun() results in the compiler failing to find module A. Calling SomeTrait::fun() does not throw an error, and the print command is executed. However, if a second struct is defined also implementing SomeTrait, then SomeTrait::fun() throws an error as it is unable to infer enough type information. I am unable, then, to find a way to run either struct's version of fun().

I would guess that traits just shouldn't be allowed non-member functions and trying to define them should throw an error.

[strega-nil]

I'm having exactly the same problem.

[sfackler]

Dup of #18490