Single result for a dependency error

[TyOverby]

I have a top level depencency on https://github.com/PistonDevelopers/rust-graphics.git and a transitive dependency on https://github.com/pistondevelopers/rust-graphics.

Note the different capitalization and lack of .git.

I get the error

An unknown error occurred                                            

Caused by:                                                           
  Temporarily, Cargo only supports a single result for a dependency  

This error had me scratching my head for a while, but I eventually managed to locate what was actually happening.

A better error message in this case would have helped me out a bunch. Something like:

For the crate rust-graphics there are two listed dependencies:
    https://github.com/PistonDevelopers/rust-graphics.git
    https://github.com/pistondevelopers/rust-graphics

[alexcrichton]

This specific case may have been fixed by #88 with URL canonicalization. This is still a real issue, however.

[alexcrichton]

Aha, otherwise closing as a dupe of #65