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digitalmars.D.bugs - [Issue 6200] New: [GSoC] Value returned by function cannot be passed as ref const.

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=6200

           Summary: [GSoC] Value returned by function cannot be passed as
                    ref const.
           Product: D
           Version: D2
          Platform: All
        OS/Version: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: cristi.cobzarenco gmail.com


--- Comment #0 from Cristi Cobzarenco <cristi.cobzarenco gmail.com> 2011-06-23
12:23:27 PDT ---
struct Test {}

void takes( ref const Test x ) {}

Test gives() { return Test(); }

int main() {
    takes( Test() );     // compiles
    // takes( gives() ); // doesn't compile
    readln();

    return 0;
}

Is this required behaviour? The compiler complains about gives() not being an
lvalue, but the code doesn't seem to require it to be an lvalue.

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next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=6200


kennytm gmail.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |kennytm gmail.com


--- Comment #1 from kennytm gmail.com 2011-06-23 13:03:36 PDT ---
No 'ref' does require the parameter as an lvalue, even if 'const' is present.
This is different from C++. I think it's a duplicate of bug 3167.

Also, the struct literal 'Test()' currently returns an lvalue, not an rvalue.
See bug 5889.

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--- Comment #2 from Cristi Cobzarenco <cristi.cobzarenco gmail.com> 2011-06-23
13:08:14 PDT ---
(In reply to comment #1)

 No 'ref' does require the parameter as an lvalue, even if 'const' is present.
 This is different from C++. I think it's a duplicate of bug 3167.
 
 Also, the struct literal 'Test()' currently returns an lvalue, not an rvalue.
 See bug 5889.


Aha, I guess you're right, I assumed that const would fix it (bug 3167 only
talks about normal refs), 'in' works though.

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--- Comment #3 from kennytm gmail.com 2011-06-23 13:11:37 PDT ---
(In reply to comment #2)

 (In reply to comment #1)

 No 'ref' does require the parameter as an lvalue, even if 'const' is present.
 This is different from C++. I think it's a duplicate of bug 3167.
 
 Also, the struct literal 'Test()' currently returns an lvalue, not an rvalue.
 See bug 5889.


 
 Aha, I guess you're right, I assumed that const would fix it (bug 3167 only
 talks about normal refs), 'in' works though.


Bug 3167 does talk about 'const ref' in the later comments, e.g.
http://d.puremagic.com/issues/show_bug.cgi?id=3167#c12.

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Cristi Cobzarenco <cristi.cobzarenco gmail.com> changed:

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


--- Comment #4 from Cristi Cobzarenco <cristi.cobzarenco gmail.com> 2011-06-23
13:15:13 PDT ---
(In reply to comment #3)

 (In reply to comment #2)

 (In reply to comment #1)

 No 'ref' does require the parameter as an lvalue, even if 'const' is present.
 This is different from C++. I think it's a duplicate of bug 3167.
 
 Also, the struct literal 'Test()' currently returns an lvalue, not an rvalue.
 See bug 5889.


 
 Aha, I guess you're right, I assumed that const would fix it (bug 3167 only
 talks about normal refs), 'in' works though.


 
 Bug 3167 does talk about 'const ref' in the later comments, e.g.
 http://d.puremagic.com/issues/show_bug.cgi?id=3167#c12.


You're right again, sorry. I looked through the comments, but somehow didn't
see that one. I'll mark this as invalid.

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