@LegNeato could you add a little description just to give me some context? Where does ARTIFACT_SUFFIX come from?

Sure! ARTIFACT_SUFFIX is defined in that file as the same static string. The suffix is for json metadata that is written out next to the artifact...sort of an API between the compiler backend and spirvbuilder. It appears to only be written with certain crate types. I was debugging another issue and saw that in the same file it uses the hardcoded string and the constant in different places, likely just an oversight:

https://github.com/Rust-GPU/rust-gpu/pull/218/files#diff-84c98121dbc8466f5e6e1503a3771f2ec4f8f37fa048ebf01c201b1b5cd1b191R903