In one of my projects, I test with Rust releases back to 1.4 on CI. Recently the build broke for Rust 1.4 through 1.6 without any changes to my code. My library transitively (but not directly) depends on the
gcc crate, of which the current version (0.3.37) fails to compile with Rust 1.4 through 1.6. Because the project is a library, I did not put cargo.lock under source control, so the most recent version is used on CI.
gcc crate works fine with a recent version of Rust, and I don’t really want to lock it to an old version. On the other hand, an older version of the crate worked fine with Rust 1.4 through 1.6, so I see no reason to drop support for those; I’m not using any of the newer features myself.
What would be the best course of action here? I suppose RFC #1709 would help in the future. Is there anything that can be done currently?