I assume requiring a very specific compiler version would still satisfy the letter of the license. The compiler is publicly available, so you could replace the

I assume requiring a very specific compiler version would still satisfy the letter of the license. The compiler is publicly available, so you could replace the LGPL part. You get no promises about being able to replace or even maintain anything else. BTW, Rust's objects/rlibs may contain bitcode and a high-level form of generic/inlineable code, so they should be much easier to reverse/decompile than an optimized binary. If the goal was to keep the non-LGPL part closed, it won't work well.