- Narrowing `x + c < b` and its other comparison forms subtracted the offset from the bound in floating point. A fractional bound could then round across an integer: `x + 2147483648 > -(2 ** -60)` gave the minimum -2147483647, which leaves out -2147483648. The bound now rounds to an integer first, and the offset comes off in exact integer arithmetic. Integer bounds give the same facts as before.
- A unit test covers that comparison.