www.digitalmars.com         C & C++   DMDScript  

digitalmars.D.bugs - [Issue 10516] New: Array length is not checked when array is a manifest constant

reply d-bugmail puremagic.com writes:
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
-- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Jun 30 2013
parent d-bugmail puremagic.com writes:
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.. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Jun 30 2013