Error in serde_derive patch


I am working on mozilla firefox open source and it has dependency in using rust.(I have no knowledge in rust and its working fine). I upgraded my OS from macos sierra to mojave. Then when I try to compile my build it generated the following error.
error: failed to resolve patches for Caused by
patch for serde_derive in did not resolve to any crates. If this is unexpected, you may wish to consult:

I have gone through “” but I don’t think I have similar reason to reproduce the error.

Can anyone help ?


Delete Cargo.lock file and try again.


Still Same Issue