pseudo-never was too short-sighted and caused wrong inferences in mut… #368

Job	Run time
testing-on-dart-stable (ubuntu-latest)	2m 24s
testing-on-dart-stable (macOS-latest)	3m 5s
testing-on-dart2 (ubuntu-latest)	1m 50s
testing-on-dart2 (macOS-latest)	2m 3s
	9m 22s

Provide feedback