I recently stumbled across Microsoft's research programming language
Koka. What I specifically found interesting about it was this:
Perceus is an advanced compilation method for reference counting.
Together with evidence translation, this lets Koka compile directly to C code without needing
a garbage collector or runtime system.
Perceus also performs reuse analysis and optimizes
functional-style programs to use in-place updates when possible (see the benchmarks).
(The links go to papers with more information.)
It was previously stated somewhere that a simple garbage collection strategy is used with Felix to maintain compatibility with C/C++. However, this language has a compilation strategy that is called "functional, but in place," or FBIP that allows it to avoid using a garbage collector and maintain compatibility with C.
Might be worth looking into.