http://d.puremagic.com/issues/show_bug.cgi?id=4675

           Summary: Eponymous Template should hide internal names
           Product: D
           Version: D2
          Platform: Other
        OS/Version: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody@puremagic.com
        ReportedBy: andrej.mitrovich@gmail.com


--- Comment #0 from Andrej Mitrovic <andrej.mitrovich@gmail.com> 2010-08-18 13:19:16 PDT ---
Code:

import std.stdio;
void main()
{

}

template isNumeric(T)
{
    enum bool test1 = is(T : long);     // should be hidden
    enum bool test2 = is(T : real);     // should be hidden
    enum bool isNumeric = test1 || test2;
}

unittest
{
    static assert(isNumeric!(int).test1);   // should be an error
    writeln(isNumeric!(int).test1);         // should be an error, but writes
true
    writeln(isNumeric!(int).test2);         // should be an error, but writes
true
}

According to TDPL, calling isNumeric!(T) is rewritten by the compiler to
isNumeric!(T).isNumeric, therefore hiding access to any other names.

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Torarin <torarin@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |torarin@gmail.com


--- Comment #1 from Torarin <torarin@gmail.com> 2010-08-20 17:26:26 PDT ---
I ran into trouble with this example as well, but this time because what should work, doesn't:

import std.stdio;

template isNumeric(T)
{
  enum bool test1 = is(T : long);
  enum bool test2 = is(T : real);
  enum bool isNumeric = test1 || test2;
}

void main()
{
  bool a = isNumeric!int;
}


Fails with:
test.d(12): Error: expression isNumeric!(int) is void and has no value.

I was surprised to find that the language reference actually contradicts TDPL here:

"Implicit Template Properties
If a template has exactly one member in it, and the name of that member is the
same as the template name, that member is assumed to be referred to in a
template instantiation."


(In reply to comment #0)
>
> According to TDPL, calling isNumeric!(T) is rewritten by the compiler to
> isNumeric!(T).isNumeric, therefore hiding access to any other names.

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--- Comment #2 from Andrej Mitrovic <andrej.mitrovich@gmail.com> 2010-08-20 17:35:05 PDT ---
There are more cases of contradiction, but I think this has to do with some of the spec not being updated. In other cases some features are simply not yet implemented.. My guess is that this feature should be implemented like it states in TDPL.

Otherwise for any non-trivial templates you would have to write code like:

isNumeric!(int).isNumeric

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--- Comment #3 from Torarin <torarin@gmail.com> 2010-08-20 17:54:25 PDT ---
Yes. std.traits deals with it by doing

private template hasRawAliasing(T...)
{
    enum hasRawAliasing
        = hasRawPointerImpl!(RepresentationTypeTuple!(T)).result;
}

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bearophile_hugs@eml.cc changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bearophile_hugs@eml.cc


--- Comment #4 from bearophile_hugs@eml.cc 2010-08-27 16:26:55 PDT ---
Time ago some people have proposed to allow "private" for that purpose:

template isNumeric(T) {
    private enum bool test1 = is(T : long);
    private enum bool test2 = is(T : real);
    enum bool isNumeric = test1 || test2;
}


This is good because the person that reads the code doesn't need to remember the rule that test1 and test2 become invisible if isNumeric is defined inside isNumeric(). So I think this is a more tidy solution to the problem.

On the other hand you want all names to be private but the one that is eponymous, so the solution in TDPL is shorter (and probably acceptable still).

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Kenji Hara <k.hara.pg@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |patch


--- Comment #5 from Kenji Hara <k.hara.pg@gmail.com> 2011-12-31 05:39:13 PST ---
https://github.com/D-Programming-Language/dmd/pull/590

Eponymous member always hides other members (do not consider access
attributes).

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Walter Bright <bugzilla@digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |bugzilla@digitalmars.com
         Resolution|                            |FIXED


--- Comment #6 from Walter Bright <bugzilla@digitalmars.com> 2012-01-15 19:17:09 PST ---
https://github.com/D-Programming-Language/dmd/commit/91facb7b443bb61793b045fab9715be633f1aa99

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--- Comment #7 from dawg@dawgfoto.de 2012-01-22 01:37:35 PST ---
*** Issue 2640 has been marked as a duplicate of this issue. ***

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Denis <verylonglogin.reg@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |verylonglogin.reg@gmail.com


--- Comment #8 from Denis <verylonglogin.reg@gmail.com> 2012-01-25 02:06:38 MSK ---
Still doesn't work in most real-life (Phobos) cases. Filled Issue 7363.

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