Compiling Rust to WebAssembly is still difficult. On macOS, there are weird bugs that require reinstalling LLVM and moving files around. On Linux, the official Emscripten binary in many cases isn’t bundled with the right LLVM, and the fix is to compile from scratch, a multi-hour process. In Travis CI, the standard “solution” is to install an Alpine Linux chroot to get the latest Emscripten. It’s a