strange _sort_ of bug

[David Medlock]

I am getting an Access Violation using the array built-in sort.

My structure looks quite harmless:

class   EdgeInfo
{
   int     from, to;
   float   cost = 0;

   public int     opCmp( Object o )
   {
     EdgeInfo e = cast(EdgeInfo)o;
     float other = e.cost;
     if ( cost < other ) return -1;
     if ( equal( other , cost ) ) return 0; else return 1;
   }
}

if I use an external sort the problem doesnt occur.
If I change it to a class(and change the opCmp) it still happens.

Moving this to a test case file makes it vanish, and its a fairly 
lengthy routine (3d Mesh simplification).

The error occurs here:

Thread stopped.
MVIEW!_D6object8TypeInfo4swapFPvPvZv+0x1a

TypeInfo.swap() ??

stop occurs at 0x0041bf86 in the following:

_D6object8TypeInfo4swapFPvPvZv:
0x0041bf6c 50               push        eax
0x0041bf6d 8b08             mov         ecx,dword ptr [eax]
0x0041bf6f 53               push        ebx
0x0041bf70 31db             xor         ebx,ebx
0x0041bf72 55               push        ebp
0x0041bf73 56               push        esi
0x0041bf74 8b742414         mov         esi,dword ptr [esp+14]
0x0041bf78 57               push        edi
0x0041bf79 8b7c241c         mov         edi,dword ptr [esp+1c]
0x0041bf7d ff5124           call        dword ptr [ecx+24]
0x0041bf80 89c5             mov         ebp,eax
0x0041bf82 85c0             test        eax,eax
0x0041bf84 7411             je 
_D6object8TypeInfo4swapFPvPvZv+0000002b (0041bf97)
0x0041bf86 8a143b           mov         dl,byte ptr [edi+ebx]
0x0041bf89 8a0c33           mov         cl,byte ptr [esi+ebx]
0x0041bf8c 880c3b           mov         byte ptr [edi+ebx],cl
0x0041bf8f 881433           mov         byte ptr [esi+ebx],dl
0x0041bf92 43               inc         ebx
0x0041bf93 39eb             cmp         ebx,ebp
0x0041bf95 72ef             jb 
_D6object8TypeInfo4swapFPvPvZv+0000001a (0041bf86)
0x0041bf97 5f               pop         edi
0x0041bf98 5e               pop         esi
0x0041bf99 5d               pop         ebp
0x0041bf9a 5b               pop         ebx
0x0041bf9b 58               pop         eax
0x0041bf9c c20800           retn        0008
0x0041bf9f cc               int         3

Any tips would be helpful.
-DavidM