• d-bugmail puremagic.com (39/39) Nov 09 2011 http://d.puremagic.com/issues/show_bug.cgi?id=6924
• d-bugmail puremagic.com (18/18) Nov 12 2011 http://d.puremagic.com/issues/show_bug.cgi?id=6924

d-bugmail puremagic.com writes:

http://d.puremagic.com/issues/show_bug.cgi?id=6924

           Summary: An alias this problem to implement a Typedef
           Product: D
           Version: D2
          Platform: x86
        OS/Version: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: bearophile_hugs eml.cc


--- Comment #0 from bearophile_hugs eml.cc 2011-11-09 20:03:18 PST ---
I find typedef useful still. While trying to create something like a typedef
using a struct with "alias this", I have found this problem:



struct Typedef(T) {
    T data;
    alias data this;
}

alias int[] TA1;
typedef int[] TA2;
alias Typedef!(int[]) TA3;

immutable TA1 a1;
immutable TA2 a2;
TA3 a3a;
immutable TA3 a3b;

static this() {
    a1 = [1, 2, 3];  // OK
    a2 = [1, 2, 3];  // OK
    a3a = [1, 2, 3]; // OK
    a3b = [1, 2, 3]; // line 16, error
}
void main() {}



DMD 2.057beta gives:

test.d(16): Error: cannot implicitly convert expression ([1,2,3]) of type int[]
to immutable(Typedef!(int[]))

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d-bugmail puremagic.com writes:

http://d.puremagic.com/issues/show_bug.cgi?id=6924


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

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


--- Comment #1 from Kenji Hara <k.hara.pg gmail.com> 2011-11-12 06:56:29 PST ---
I think this is a same issue with bug 6174.

The assignment expression

  a3b = [1, 2, 3];

is translated to

  a3b.data = [1, 2, 3];

, and current dmd does not allow indirect initialization of members with
assignment.

*** This issue has been marked as a duplicate of issue 6174 ***

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