https://pharo.fogbugz.com/f/cases/7558/ says it's fixed, but I still get the bug in 30541.

Changing NECContext>>#sourceOf: aSHRange stopAt: aNumber

to always return "source copyFrom: aSHRange start to: aNumber" seems to fix it. But I don't know why the original was returning String new when aSHRange type = #empty

So maybe it breaks something else? The tests still run.