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digitalmars.D.bugs - [Issue 6374] New: [CTFE] Cannot subscript using pointer to array

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=6374

           Summary: [CTFE] Cannot subscript using pointer to array
           Product: D
           Version: D2
          Platform: Other
        OS/Version: Mac OS X
            Status: NEW
          Keywords: rejects-valid
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: kennytm gmail.com



Test case:

---------------------
static assert({
    int[] arr = [1];
    arr.ptr[0] = 2;   // <-- line 3
    return arr[0];
}() == 2);
---------------------
y.d(3): Error: cannot determine length of cast(int*)arr at compile time
y.d(5): Error: cannot evaluate delegate pure nothrow int()
{
int[] arr = [1];
(cast(int*)arr)[0u] = 2;
return arr[0u];
}
() at compile time
y.d(1): Error: static assert  (delegate pure nothrow int()
{
int[] arr = [1];
(cast(int*)arr)[0u] = 2;
return arr[0u];
}
() == 2) is not evaluatable at compile time
---------------------

Slicing is OK, though.

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next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=6374




Note that this prevents std.array.appender from being CTFE-able, because it
contains the code:

                _data.arr.ptr[len] = cast(Unqual!T)item;  // <-- error
                _data.arr = _data.arr.ptr[0 .. len + 1];  // (OK)

Currently, this could be worked-around by swapping the two statements and use
the standard indexing:

                _data.arr = _data.arr.ptr[0 .. len+1];  // OK
                _data.arr[len] = cast(Unqual!T)item;    // now OK

but I think the more proper solution is to fix this bug.

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prev sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=6374


Walter Bright <bugzilla digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |bugzilla digitalmars.com
         Resolution|                            |FIXED



15:18:37 PDT ---
https://github.com/D-Programming-Language/dmd/commit/0904c8aa200e4d080d500d96d5904c33ba17cc86

https://github.com/D-Programming-Language/dmd/commit/e48a8c67f02172c72e04f36759d2d6868d716368

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