checkedint call removal

[Walter Bright via Digitalmars-d]

On 8/2/2014 1:06 PM, Artur Skawina via Digitalmars-d wrote:
> There's nothing wrong with `assume`, it's very useful for optimizations.
> But it's too dangerous to tack `assume` onto `assert`. If they are kept
> separate then it's at least possible to carefully audit every 'assume'.
> People *will* use them for micro-optimizations, and they *will* make
> mistakes.

This seems contradictory. You say it is fine to have assume affect 
optimization, i.e. insert bugs if the assumes are wrong, but not fine to 
check at runtime that the assumes are correct?