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digitalmars.D.bugs - [Issue 9069] New: struct literals are treated as lvalues

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=9069

           Summary: struct literals are treated as lvalues
           Product: D
           Version: unspecified
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: jmdavisProg gmx.com



PST ---
I thought that we'd finally fixed this, but I guess that it was changed back
for some reason. With this code,

struct S
{
    int i;
}

S foo(ref S s)
{
    return s;
}

S bar(int i)
{
    return S(i);
}

void main()
{
    S s = S(2);
    foo(s);  //compiles as it should
    foo(S(5)); //compiles when it shouldn't
    foo(bar(5)); //fails to compile as it should
}

only the final call to foo gives an error, when only the first call should
compile. The second call is succeeding when it should be failing.

It makes _no_ sense to treat struct literals as lvalues. They're _not_
variables. Why on earth would struct literals be treated any differently from
string literals or numeric literals in this regard? When it's come up in the
newsgroups, I believe that the only person who has thought that this made any
sense at all is Walter. And I thought that we'd finally gotten him to change it
so that struct literals act like every other literal and are rvalues, but given
that foo(S(5)) compiles, clearly that's not the case. It should be fixed.

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Nov 24 2012
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=9069


Andrej Mitrovic <andrej.mitrovich gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |andrej.mitrovich gmail.com



03:04:42 PST ---
I think this is the pull that should have fixed this:
http://d.puremagic.com/issues/show_bug.cgi?id=5889

Also since a recent pull this (correctly) no longer compiles:

struct S { }
void test(ref S s = S()) { }

So I think we've definitely agreed that literals are r-values. Maybe the OP
code compiles because of an oversight or wrong revert?

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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PST ---
It was discussed in the thread on const ref in the dmd-beta group during the
preparations for releasing 2.060, and I think that it was fixed and then
unfixed then, but I'm not sure. Regardless, the code here compiles when it
shouldn't, and that needs to be fixed.

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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 It was discussed in the thread on const ref in the dmd-beta group during the
 preparations for releasing 2.060, and I think that it was fixed and then
 unfixed then, but I'm not sure. Regardless, the code here compiles when it
 shouldn't, and that needs to be fixed.


This behavior is introduced in 2.059beta by:
https://github.com/D-Programming-Language/dmd/pull/874

As far as I know, the main purpose was to avoid breaking existing code:

struct S {
  bool opEquals(const ref S rhs) { ... }
}
void main() {
  S s;
  assert(s == S());  // translated to s.opEquals(S())
}

But, I believe the behavior should be *fixed*.

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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Kenji Hara <k.hara.pg gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |pull
            Version|unspecified                 |D2



https://github.com/D-Programming-Language/dmd/pull/1319

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prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=9069


Andrej Mitrovic <andrej.mitrovich gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mrmocool gmx.de



10:59:44 PST ---
*** Issue 7513 has been marked as a duplicate of this issue. ***

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Dec 02 2012
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=9069




Commits pushed to master at https://github.com/D-Programming-Language/dmd

https://github.com/D-Programming-Language/dmd/commit/5fb1348103930045604835ac40bb3a84106c7bf0
fix Issue 9069 - struct literals are treated as lvalues

https://github.com/D-Programming-Language/dmd/commit/5b8827f3db5affdd4534cf131492fd92c6e10269


Issue 9069 - struct literals are treated as lvalues

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Dec 03 2012
prev sibling next sibling parent d-bugmail puremagic.com writes:
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Commit pushed to master at https://github.com/D-Programming-Language/phobos

https://github.com/D-Programming-Language/phobos/commit/afed048033d976482739945f9ca4e8ca14271264


By fixing bug 9069 and 9035, T.init always returns rvalue and ref cannot
receive it.

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prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=9069




Commit pushed to master at https://github.com/D-Programming-Language/dmd

https://github.com/D-Programming-Language/dmd/commit/acf8a8934dff6b9cdfcc4d5f98b9b5c242b11ebd


By fixing bug 9069 and 9035, T.init always returns rvalue and ref cannot
receive it.

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Dec 03 2012
prev sibling parent d-bugmail puremagic.com writes:
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Kenji Hara <k.hara.pg gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED


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Dec 17 2012