No worries, I'm just surprised you managed to find a simple testcase that exhibits it, so, really, thank you!

I've opened a (a bit vague for now) issue so at least I don't forget about it: https://github.com/rust-lang/rust/issues/44041

As for phase ordering - someone did show me recently VSDG, which claims to solve at least part of the problem (specifically, https://www.cl.cam.ac.uk/techreports/UCAM-CL-TR-705.pdf and http://sro.sussex.ac.uk/7576/1/Stanier%2C_James.pdf).