radare2 [1] project is also working on a decompiler, which uses ESIL [2] intermediate language as a source and lifts it to the RadecoIL, whish is then simplified and transformed to C. The missing parts now are mostly Memory SSA, C AST generation (partially done) and Type Inference. The decompiler itself written in Rust and uses the radare2 as a source of ESIL and other metainformation. Using the ESIL as a source will allow to implement the support for a different architectures, not only the common ones. Currently we're running RSoC - Radare Summer of Code [3], and hope that our 2 students will make the significant progress on both Rune (Symbolic Execution on top of ESIL) and Radeco projects. And we are always happy to welcome a new potential contributors to all underlying projects, including radare2 itself. If you want to help us - please join #radare IRC channel or #radare Telegram channel [4].
The sources of Radeco are located at https://github.com/radare/radeco-lib
I'll preface this by saying that I love radare2. It's my goto tool when I don't need to share work with IDA/Binja users and don't need to decompile something.
The radeco project is a train wreck. The current state of radeco-lib (unless it's been remediated in the last month) is disappointing and the only reason it compiles is because the last SoC student appears to have commented out the bindings that radeco is meant to use to get radeco-lib to do anything. I actually spent an evening attempting to undo that absurd series of commits but after getting a lot of the commented out back in place, not being a Rust programmer, hit roadblocks I did not understand regarding types and traits.
Unsolicited advice incoming. Please keep a close eye on your RSoC students this year. Their goals to achieve anything which they can present do not necessarily grok with the ongoing health of your project. I'd also love it if you would drop Rust and work with a more accessible language, at least while you work toward an initial version which spits out something resembling C code. Ultimately it's your project so do whatever you want but IMHO making everyone understand an inherently complex project in a language which is not straightforward is not the best option. Or at least add some documentation and make your lib and program build together...
[1] http://rada.re
[2] https://radare.gitbooks.io/radare2book/content/disassembling...
[3] http://radare.today/posts/RSOC-2017/
[4] https://telegram.me/joinchat/ACR-FkEK2owJSzMUYjt_NQ