runUnion stops GHC helping us out with case exhaustivity checking.
In the course of making this PR and getting the benefit of GHC's assistance, I discovered that we weren't handling AArch64 properly, which is an obvious and easily corrected oversight.
It's also made two other incomplete matches visible, but they're slightly less obviously corrected. As this PR isn't making things worse, only revealing problems that already existed, I've elected to leave those as they are.
runUnion
stops GHC helping us out with case exhaustivity checking.In the course of making this PR and getting the benefit of GHC's assistance, I discovered that we weren't handling
AArch64
properly, which is an obvious and easily corrected oversight.It's also made two other incomplete matches visible, but they're slightly less obviously corrected. As this PR isn't making things worse, only revealing problems that already existed, I've elected to leave those as they are.