tupleof seems to break encapsulation

[Simen Kjærås]

On Friday, 4 September 2020 at 10:16:47 UTC, 60rntogo wrote:
> Consider the following code.
>
> foo.d
> ---
> module foo;
>
> struct Foo
> {
>   private int i;
> }
> ---
>
> main.d
> ---
> void main()
> {
>   import std.stdio;
>   import foo;
>
>   auto x = Foo();
>   writeln(x);
>   // ++x.i;
>   ++x.tupleof[0];
>   writeln(x);
> }
> ---
>
> As expected, the commented line does not compile. If I 
> uncomment it, I get the error "no property i for type foo.Foo". 
> However, the rest of the code compiles just fine and outputs:
> ---
> Foo(0)
> Foo(1)
> ---
>
> This appears to defeat the purpose of declaring i private. What 
> am I missing?

It's a known issue: https://issues.dlang.org/show_bug.cgi?id=19326

There are some very good reasons to allow some access to private 
fields, though it should be more limited than is currently the 
case.

--
   Simen