Conflict with private symbol from an imported module

[H. S. Teoh]

On Thu, Jan 23, 2014 at 05:38:03PM +0000, Nicolas Sicard wrote:
> On Thursday, 23 January 2014 at 17:29:08 UTC, Gary Willoughby wrote:
> >On Thursday, 23 January 2014 at 17:06:17 UTC, Nicolas Sicard
> >wrote:
> >>Hi,
> >>
> >>I known this has been discussed before, and there still is an
> >>open issue in bugzilla
> >>(https://d.puremagic.com/issues/show_bug.cgi?id=1238). Is it
> >>considered a feature or a bug?
> >>
> >>Thanks
> >
> >Modules are broken in several ways:
> >https://d.puremagic.com/issues/show_bug.cgi?id=314
> 
> It sure is broken. But I wondered if it would be let aside. I say
> this because I think I remember reading (from Walter?) that it would
> need a significant re-implementation to fix it.

Reimplementation or not, I consider this a major bug. This has actually
happened to me with Phobos:

1) In an earlier version of D, I had a module stack.d that declares a
public symbol 'Stack', and another module mod.d that imports module
stack and also std.regex.

2) In the meantime, Dmitri revised the implementation of std.regex and
in the process introduced a *private* symbol Stack. These changes are
merged into Phobos and included in the subsequent release.

3) I upgrade dmd to the subsequent release, and suddenly my code has a
compile error, because the *public* symbol stack.Stack conflicts with
the *private* symbol std.regex.Stack.

Not only this is a major annoyance, it also breaks encapsulation because
anytime you introduce new private symbols to your library module, you
could, in theory, be breaking random user code due to these conflicts.
Why should user code care that new *private* symbols were introduced to
the module?? Such implementation details ought to be invisible to the
outside world. Yet currently, user code has to disambiguate these
conflicting symbols in order to compile.

This travesty needs to be fixed, otherwise D will just remain a laughing
stock of other languages.


T

-- 
To err is human; to forgive is not our policy. -- Samuel Adler