Rust

Fix build with some feature combinations (#619) #886

Job	Run time
msrv-read	1m 50s
coverage	1m 41s
features	57s
build (ubuntu-latest, stable)	1m 22s
build (ubuntu-latest, beta)	1m 15s
rustfmt	12s
build (ubuntu-latest, nightly)	1m 20s
cross (i686-unknown-linux-gnu)	1m 37s
build (stable, macOS-latest)	2m 45s
cross (powerpc64-unknown-linux-gnu)	1m 41s
doc	11s
msrv-all	1m 59s
	16m 50s

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