Fixing out-of-heap error due to large memory copy

[msooseth]

Description

This issue is related to #444. I am fixing it by returning IllegalOverflow, which is what we already do, although we only check $2^{64}$, not 2^{28}$. However, it's mostly the same thing -- way too large of a number.

Checklist

• tested locally
• added automated tests
• updated the docs
• updated the changelog

[arcz]

Looks good :) this error is annoying

[msooseth]

Thanks for the review!