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digitalmars.D.bugs - [Issue 3550] New: array.dup violates const/invariant without a cast.

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=3550

           Summary: array.dup violates const/invariant without a cast.
           Product: D
           Version: 2.036
          Platform: Other
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: schveiguy yahoo.com


--- Comment #0 from Steven Schveighoffer <schveiguy yahoo.com> 2009-11-24
19:47:31 PST ---
simple test case:

import std.stdio;

class C { int x; }

void foo(const(C)[] arg)
{
  auto arg2 = arg.dup;
  foreach(c; arg2) c.x = 5;
}

void main()
{
  C[] arr;
  arr ~= new C;
  foo(arr);
  writefln("%d", arr[0].x);
}

This compiles and outputs 5.

I believe dup should statically fail if the element type has any references in
it and the type is const or invariant.

Likewise, I think idup should fail if the element type has any references in
it.  These properties are not supposed to be "you're on your own" territory
IMO.

This is related to bug 1339

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next sibling parent d-bugmail puremagic.com writes:
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--- Comment #1 from Steven Schveighoffer <schveiguy yahoo.com> 2009-11-24
20:02:10 PST ---
I should clarify:

I think idup should fail if the element has any *non-immutable* references in
it.

Note this leaves us with no ways to dup a const array with references in it! 
Should we have cdup?  A workaround to both would be to always allow dup when an
explicit cast is involved.

i.e.:

auto arg2 = cast(const(C)[])arg.dup;

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prev sibling parent d-bugmail puremagic.com writes:
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Sobirari Muhomori <dfj1esp02 sneakemail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Blocks|                            |2573


--- Comment #2 from Sobirari Muhomori <dfj1esp02 sneakemail.com> 2010-08-03
13:25:17 PDT ---
Just thought, there must be this bug...

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Aug 03 2010