Not sure .. is this a bug?

[Frits van Bommel]

Downs wrote:
> import std.stdio;
> 
> class foo { int e; abstract const void bar(); }
> 
> class bug: foo { void bar() { writefln("I NOW CHANGEZ TEH OBJECTS"); e=5; } }
> 
> void main() {
>   const(bug) okay=new bug;
>   // okay.bar; fails as expected
>   const(foo) Bug=cast(foo)okay;
>   Bug.bar; // interestingly works.
> }
> 
> From my POV, the Bug.bar is modifying data it shouldn't be able to modify, but then again, I'm rather new to the whole constness thing. So, is this a bug?

I'd have expected the compiler to give an error when trying to override 
"const void bar()" with "void bar()" in 'bug'...