stage2: able to slice to sentinel index at comptime
The runtime behavior allowed this in both stage1 and stage2, but stage1
fails with index out of bounds during comptime. This behavior makes
sense to support, and comptime behavior should match runtime behavior. I
implement this fix only in stage2.
a36f4ee290Mitchell Hashimoto committed on 3/23/2022, 9:08:08 PM· committed by Andrew Kelleyparentf27d340