Confusing error when using import globbing in test module

[bkoropoff]

Problem

Using import globbing in a test module results in a very confusing error.

Code

#![feature(globs)]

mod test {
    use super::*;

    #[test]
    fn test(){}
}

Output

$ rustc --test test.rs 
test.rs:4:9: 4:18 error: import conflicts with type in this module
test.rs:4     use super::*;
                  ^~~~~~~~~
test.rs:1:1: 1:1 note: note conflicting type here
test.rs:1 #![feature(globs)]
          ^
error: aborting due to previous error

After some digging, it turns out the conflict is on __test_reexports. I plan to submit a PR to at least print the name of the conflicting import in the above error message so there's something to go on.

[samdoshi]

Is using use super::*; in test modules discouraged now? (see http://aturon.github.io/style/imports.html)

For anyone wishing to temporarily work around this issue, you can re-enable import shadowing with the following feature gate #![feature(import_shadowing)]

[SimonSapin]

CC @pcwalton (as author of 7f928d1)

[SiegeLord]

The error message really should mention that that gate is an option.

[pcwalton]

The gate will probably be removed in the future, so I'd rather not encourage people to depend on it.

[sfackler]

@samdoshi it's just a bug.

Should be an easy-ish fix by gensyming each __test_reexports separately.

[SimonSapin]

@sfackler what’s gensyming? Symbol generation, as in giving them different names?

[sfackler]

Yeah, giving each reexport module a name that the compiler will consider distinct from everything else in the crate.