BinaryOp: Fix a bug that would lead to one of the operands becoming None after replacing. #439

Job	Run time
windows / Test Windows	33s
ci / Build	3m 21s
macos / Test macOS	22s
ci / Lint	55s
ci / Test (0)	8m 24s
ci / Test (1)	6m 58s
ci / Test (2)	5m 25s
ci / Test (3)	7m 17s
ci / Test (4)	8m 29s
ci / Test (5)	5m 38s
ci / Test (6)	5m 11s
ci / Test (7)	4m 9s
ci / Test (8)	4m 15s
ci / Test (9)	6m 1s
ci / Publish Unit Tests Results	1s
	1h 6m 59s

Provide feedback