A compiler that makes incorrect assumptions is a bad compiler. In fact, in the rationale of the original spec., I remember reading that the C standard was expr

A compiler that makes incorrect assumptions is a bad compiler. In fact, in the rationale of the original spec., I remember reading that the C standard was expressly designed to be a minimal spec, and that just being compliant with the spec was insufficient for the resulting compiler to be fit for purpose. And of course the original spec did specify a range of acceptable behaviors, and that language is, in fact, still in the standard. It was just made non-binding. However, it is still there, and pretending it is not seems disingenuous at best.