Rust bandwagon

Fortran allows a lot of (specified) behaviour in the name of optimisation, that can lead to unexpected results. Like storing the index of a do loop in a register, such that it can only safely be read, and not relied on when the loop exits. It seems highly likely that most FORTRAN compilers (and certainly the one I was using in 1983, iirc) did not bother to check the loop limits. Given that I understood that FORTRAN explicitly said the index,limit check was done at the *end* of the loop, I would be surprised if there was a special check on entering the loop.

When Fortran moved the check to the start of the loop, then it makes sense that loops can execute zero times.

Cheers,
Wol