name resolution and warnings inconsistent

[metajack]

When using use foo::{FooTypeA, FooTypeB}; and use foo; together, the compiler complains that use foo; is an unused import even when a call to something like foo::hello() exists. Removing use foo; gets rid of the warning and the crate compiles. However, the crate will fail to link (for example with --test) unless the use foo; is there.

It seems like the warning is a bug unless the intent is to have use foo::{FooTypeA, FooTypeB}; also bring in foo itself.

Here's a small crate that shows the example. This was originally found in rust-core-foundation.

https://gist.github.com/metajack/5249056

[alexcrichton]

Looking at the code, that's a genuinely unused import when not compiling with --test.

I ran into this when removing unused imports in the compiler, and you can prefix the import with #[cfg(test)] so that the import is only resolved when testing. Other options I've seen are to have a mod test which is cfg'd off, or just put the use in the function itself.

[metajack]

You're right. In this case I moved the use foo; inside the test function.