Improve handling of `?`-variables #1964

Job	Run time
Nix / All Tests (self-hosted, linux, normal, Ubuntu-22.04, x86_64-linux)	9m 11s
Formatting and Style	25s
Stack / Unit Tests	1m 42s
Nix / All Tests (MacM1, self-macos-12, aarch64-darwin)	7m 16s
Nix / All Tests (macos-12, macos-12, x86_64-darwin)	24m 0s
	42m 34s

Provide feedback