In Go I can only write libraries for Go programs. In Rust I can write libraries for any program.
i.e. Rust can easily produce static and dynamic libraries that are linkable with C programs and any language with a C FFI. I can write Rust code that works for programmers using C, C++, C#, D, Go, Swift, Python, PHP, Java, etc.
http://www.darkcoding.net/software/building-shared-libraries...
That's not true. It's quite simple to create a loadable shared object in go and call it using anything with a c ffi.
As proof, notice that it barely happens, and only as an oddity in Go, yet in rust there are actual uses (e.g. ruby and python library optimization)
[1] https://www.cockroachlabs.com/blog/the-cost-and-complexity-o...