I came across the SOIL-initiative which aims to create a Single Open Intermediate Language. I believe perhaps if there is a collaboration with this initiative it might be of mutual benefit for this project also. This can help further research in IR, optimisation of IR, better targeting of web and other platforms, etc.
I remember doing some extensive googling back when I first heard about SOIL, and couldn't find any technical documents, demos, proposed syntax, etc. Since the landing page hasn't changed since, I assume that's still the case.
I doubt Rust has anything to gain by associating with SOIL this early. So far this project is at the "A lot of very smart people have promised to do the exact same thing you're trying to do, and so far you haven't shown any evidence you'll succeed where they failed" stage (no offense to the project researchers).
I'd wait until they at least publish a toy syntax to get excited.
It looks like this project is geared toward managed languages instead of unmanaged languages like Rust:
We want to design a means for garbage-collected languages to communicate their memory layouts and low-level feature implementations within an extended WebAssembly.
We need a garbage collector that can manage memory across programs from multiple languages with different layouts.
While interesting, this doesn't seem to be a good fit for Rust.
Their github organization (https://github.com/soil-initiative) has more technical content. Essentially they're introducing new proposals for the WebAssembly standard to help bring more diverse languages to WebAssembly. However, it is extremely unlikely that Rust will end up using any of these new proposals because WebAssembly already has everything necessary to support LLVM-based languages with small runtimes.