We'll start tackling GC as soon as we finish the MVP [0]. No timeline yet, but we consider it essential to the high level goal of integrating well into the existing platform.
[0]: https://github.com/WebAssembly/design/blob/master/GC.md
Any chance python could be a first class citizen here, or are we looking at more compile-able languages?
Check out the last paragraph of "Is WebAssembly only for C/C++ Programmers?" in the FAQ [0]. The tl;dr is that you'll be able to port a Python interpreter (that is itself written in C) to WebAssembly from day 1, but a more robust solution that relies on WebAssembly GC will have to wait until after the MVP.
[0]: https://github.com/WebAssembly/design/blob/master/FAQ.md#is-...
What are some use cases for WebAssembly in React? What source language might React use to generate the WebAssembly code?
Do you have any anticipated timeline for this? For React, at least, we're eagerly looking forward to the opportunity to write at a lower level while maintaining the same JS-facing API.