On Monday, 28 July 2014 at 09:37:27 UTC, Regan Heath wrote:
My point was that for the vast majority of coders, in the vast
majority of cases opCmp()==0 will agree with opEquals(). It is
only in very niche cases i.e. where partial ordering is
actually present and important, that this assumption should be
broken.
Yet, by default, if a user defines opCmp() the compiler
generated opEquals may well violate that assumption. This is
surprising and will lead to subtle bugs.
The cheap non-breaking solution is to just add opCmpTotal() and
map opCmp() to that. If opCmpTotal is defined then you cannot
define opCmp() and opCmp(a,b)==0 should match a==b whether
redefined or not.
