Return const object through mutable Object

[Jonathan M Davis]

On Sunday, April 15, 2012 17:57:27 Jacob Carlborg wrote:
> class Foo
> {
>      Foo f;
> 
>      Foo bar () const
>      {
>          return f;
>      }
> }
> 
> The above code results in the compile error:
> 
> Error: cannot implicitly convert expression (this.f) of type const(Foo)
> to test.Foo
> 
> But if I change "bar" to:
> 
> Object bar () const
> {
>      return f;
> }
> 
> I don't get any errors. Is the last example supposed to compile?
> 
> I'm using DMD v2.059.

It definitely looks like a bug. Whether it returns Foo or Object should have no 
effect on constness, and since f is a member variable of Foo, and the this 
pointer/reference is const, bar is going to have to return a const reference 
to it, which the second version isn't doing.

- Jonathan M Davis