Why D is annoying =P

[Jens Mueller]

Jonathan M Davis wrote:
> On Friday, October 26, 2012 19:46:16 deadalnix wrote:
> > Le 25/10/2012 04:12, Jonathan M Davis a écrit :
> > > On Wednesday, October 24, 2012 13:31:14 Walter Bright wrote:
> > >> The default compare for structs is a bit compare of the contents.
> > > 
> > > Which definitely seems inherently broken. Doing that only works if the
> > > struct only contains integral types, character types, or bool. Nothing
> > > else will compare properly that way. It really needs to work like arrays
> > > do (or are supposed to anyway) and compare each member according to ==
> > > and only fallback to an outright bitwise compare when it knows that the
> > > results would be identical (i.e. because all of the members are integral
> > > types, character types, bool, or other structs which hold only integral
> > > types, character types, or bool - be it directly or in other structs that
> > > they hold). Bitwise comparison is the is operator's job, not ==.
> > > 
> > > - Jonathan M Davis
> > 
> > That will broke code.
> > 
> > But That is the way to go IMO. D needs to evolve to make things more
> > consistent in general.
> > 
> > Still not doable without a proper versionning scheme.
> 
> TDPL clearly states that each of the struct's members are supposed to be 
> checked for equality (see section 7.1.5.2, p. 258 - 259). It's outright a bug 
> for structs to be checked for equality with a bitwise comparison when the 
> bitwise comparison does not do exactly what == would have done had each and 
> every member variable been compared with ==. And as with all bugs, fixing it 
> could break code which depends on the buggy behavior. But given the nature of 
> this bug, I seriously question that much of anyone thought that the == on 
> structs was supposed to do anything other than what TDPL states that it should 
> and that pretty much no one was expecting it to do a bitwise comparison. So, 
> if anything, this will _fix_ far more code than it breaks.

I was looking for that section. 3789 is clearly a bug and should be
fixed as soon as possible.
Votes indicate how important a bug should be. But duplicates are also a
good indicator. This bug has six duplicates.

Jens