http://d.puremagic.com/issues/show_bug.cgi?id=10516

           Summary: Array length is not checked when array is a manifest
                    constant
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody@puremagic.com
        ReportedBy: andrej.mitrovich@gmail.com


--- Comment #0 from Andrej Mitrovic <andrej.mitrovich@gmail.com> 2013-06-30 18:38:31 PDT ---
-----
void main()
{
    enum HexSize = 5;

    // note: smaller initializer count
    enum char[HexSize] srcHex = "1234";

    char[HexSize] tgtHex = "12345";

    // should error with: lengths don't match for array copy
    assert(tgtHex[0 .. 4] == srcHex);
}
-----

$ dmd test.d
> core.exception.AssertError@test(11): Assertion failure

The problem here is that the runtime allowed the left-hand side and right-hand side arrays to be compared even though their lengths do not match.

If you convert the source array from a manifest constant into a regular array (by removing enum) then the error is proper:

-----
void main()
{
    enum HexSize = 5;

    // note: smaller initializer count
    /* enum */ char[HexSize] srcHex = "1234";

    char[HexSize] tgtHex = "12345";

    assert(tgtHex[0 .. 4] == srcHex);
}
-----

$ dmd test.d
> object.Error: lengths don't match for array copy, 5 = 4

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http://d.puremagic.com/issues/show_bug.cgi?id=10516


Andrej Mitrovic <andrej.mitrovich@gmail.com> changed:

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


--- Comment #1 from Andrej Mitrovic <andrej.mitrovich@gmail.com> 2013-06-30 19:01:18 PDT ---
> -----
> void main()
> {
>     enum HexSize = 5;
> 
>     // note: smaller initializer count
>     /* enum */ char[HexSize] srcHex = "1234";
> 
>     char[HexSize] tgtHex = "12345";
> 
>     assert(tgtHex[0 .. 4] == srcHex);
> }
> -----
> 
> $ dmd test.d
> > object.Error: lengths don't match for array copy, 5 = 4

Actually this test-case is invalid because the error is thrown in the initializer line, not the comparison line.

And another thing I just realized is that it's perfectly ok to compare static arrays of non-matching sizes, which makes the whole report invalid.. but I don't understand why this is allowed:

void main()
{
    char[5] srcHex = "12345";
    char[3] tgtHex = "123";
    assert(srcHex == tgtHex);
}

$ dmd test.d
> core.exception.AssertError@test(5): Assertion failure

I would have hoped to get a length mismatch error, or even a compile-time error. Oh well..

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