Multibin dummy stub regression

[rvolosatovs]

Describe the bug

An upgrade from da87d1a to 76d64e7 introduced a regression for a crate with multiple binaries with following structure:

.
├── Cargo.lock
├── Cargo.toml
├── flake.nix
└── src
    └── bin
        ├── bye
        │   └── main.rs
        └── hello.rs

This is likely caused by #752

Reproduction

here's an example crate that breaks:
https://github.com/rvolosatovs/nixify/tree/379112688c027532fd956444b284ade07e83aea8/examples/rust-hello-multibin

refs rvolosatovs/nixify#314

[rvolosatovs]

If it helps, here's logic I use to figure out all binaries that would be built by cargo: https://github.com/rvolosatovs/nixify/blob/379112688c027532fd956444b284ade07e83aea8/lib/rust/crateBins.nix#L1-L150

[ipetkov]

Thank you for the report and the reproduction @rvolosatovs ! The issue was due to not deduping between discovered and declared bin targets, should be fixed with #755!