Same span pointed to multiple times for unused_imports lint

[estebank]

My codebase manages to produce the following output under todays nightly:

warning: the item `Foo` is imported redundantly
   --> src/lib.rs:243:9
    |
8   |   Foo, Bar,
    |   ---
    |   |
    |   the item `Foo` is already imported here
    |   the item `Foo` is already imported here
...
243 |     use foo::bar::Foo;
    |         ^^^^^^^^^^^^^
    |
    = note: #[warn(unused_imports)] on by default

I haven't been able to reduce it, but have a patch to fix it (without a test).