When we introduce rustfmt we could not get anywhere close to acceptable formatting without using config items that are only available with a nightly toolchain. This puts a burden on devs to have the nightly toolchain installed and brings with it all the hassles / security concerns of doing so - is there a better solution?

• Using stable is not, IMO, a viable solution. The result of formatting with stable is horrible, and there are way too many prickly devs in this repo to cop that.
• Removing rustfmt is explicitly out of scope for this issue, that is discussed: Remove rustfmt formatting requirement from project #2127 (review)

Is there another solution?