fjl/chipz — comment on commit 9f1917b2c3f38bce1029cdc2a5b9ccd22b2848c4
File:  line 0
By froydnj:

Hm, that doesn't sound like it should give an error.

I'm hesitant to accept the patch as-is. In particular, using MAX instead of MIN rings alarm bells; we don't want to copy as much as we can, we only want to copy "as much as we have space for" or "as much as could be copied".

Ah, I see the bug. It shouldn't be (- START END), it should be (- END START). Can you try just that adjustment, not changing the interface of COPY-EXISTING-INPUT, and see if that fixes the problem?