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digitalmars.D.bugs - [Issue 7516] New: Postblit not called for structs returned from a ternary operator

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=7516

           Summary: Postblit not called for structs returned from a
                    ternary operator
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Keywords: wrong-code
          Severity: major
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: sludwig outerproduct.org


--- Comment #0 from Sönke Ludwig <sludwig outerproduct.org> 2012-02-16 03:28:54
PST ---
Created an attachment (id=1075)
Reproduction case

Attached is a small example with a pseudo RefCount struct.
Running with the ternary operator enabled "dmd -version=BUG -run" yields:

---
1st pass
POS1: 613D80 -100
CREATE 18FDFC 1
DESTROY 18FDE0 -100 IN
DESTROY 18FDE0 -100 OUT
POS2: 613D80 1
DESTROY 18FE0C 1 IN          <- destroys the object although the static
variable
DESTROY 18FE0C -100 OUT         in func() should still hold a reference

2nd pass
POS1: 613D80 0               <- the static variable now references a destroyed
POS2: 613D80 0                  object
DESTROY 18FE0C 0 IN
DESTROY 18FE0C -1 OUT
---

The line "return cnt.cnt ? cnt : cnt;" fails to call the struct's postblit and
causes the returned object to get destroyed.

running with "dmd -run" yields the expected output:

---
1st pass
POS1: 533D80 -100
CREATE 18FDFC 1
DESTROY 18FDE0 -100 IN
DESTROY 18FDE0 -100 OUT
POS2: 533D80 1
COPY 18FE0C 2                 <- correctly copied on return
DESTROY 18FE0C 2 IN
DESTROY 18FE0C 1 OUT

2nd pass
POS1: 533D80 1
POS2: 533D80 1
COPY 18FE0C 2
DESTROY 18FE0C 2 IN
DESTROY 18FE0C 1 OUT          <- the static reference is still there
---

"return cnt;" will correctly call the postblit constructor.

Occurs for DMD 2.058 (2.57 fails for both cases)

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next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=7516


SomeDude <lovelydear mailmetrash.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |lovelydear mailmetrash.com


--- Comment #1 from SomeDude <lovelydear mailmetrash.com> 2012-04-20 00:43:05
PDT ---
See also issue 7506

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--- Comment #2 from SomeDude <lovelydear mailmetrash.com> 2012-04-20 01:01:16
PDT ---
See also issue 7530

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--- Comment #3 from Kenji Hara <k.hara.pg gmail.com> 2012-05-10 22:56:59 PDT ---
Test cases:

void main()
{
    static struct S
    {
        int val;

        this(int n) { val = n; }
        this(this) { val *= 3; }
    }

    // cond ? lvalue : lvalue
    S foo(bool f)
    {
        auto s1 = S(1), s2 = S(2);
        return f ? s1 : s2;
    }
    auto s1 = foo(true);
    assert(s1.val == 3);
    auto s2 = foo(false);
    assert(s2.val == 6);

    // cond ? rvalue : rvalue
    S bar(bool f)
    {
        return f ? S(1) : S(2);
    }
    auto s3 = bar(true);
    assert(s3.val == 1);
    auto s4 = bar(false);
    assert(s4.val == 2);

    // cond ? lvalue : rvalue
    S baz(bool f)
    {
        auto s1 = S(1);
        return f ? s1 : S(2);
    }
    auto s5 = baz(true);
    assert(s5.val == 3);
    auto s6 = baz(false);
    assert(s6.val == 2);
}

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dsimcha yahoo.com


--- Comment #4 from Kenji Hara <k.hara.pg gmail.com> 2012-05-10 23:05:16 PDT ---
*** Issue 7130 has been marked as a duplicate of this issue. ***

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