Bypassing the const promise

div0 div0 at users.sourceforge.net
Thu Nov 19 12:01:02 PST 2009


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Tomek Sowiñski wrote:
> const on a function forbids changing members:
> 
> class Wrong {
>     int a;
>     void foo() const {
>         a = 4;
>     }
> }
> 
> The above rightly doesn't compile. But with a little twist...
> 
> class A {
>     int a;
>     void foo(ref int i) const {
>         i = 4;
>     }
>     void foo() const {
>         foo(a);
>     }
> }
> 
> void main() {
>     auto a = new A;
>     a.foo;
>     assert(a.a == 4);
> }
> 
> ... I bypass the const promise on a function (two of them in fact). No casting, no evil stuff.
> 
> Is this a compiler bug or feature?
> 
> Tomek

That's definitely a bug.
Casting away const should always be explicit operation.

- --
My enormous talent is exceeded only by my outrageous laziness.
http://www.ssTk.co.uk
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