import std;

​

struct Data {

    private void[10] buf;

    private void* ptr; // some data

    //TODO. OT

    // should it be possible to initialize pointers to internals in the default constructor for structs? does DIP-xxxx(idr) solve it? whether its necessary?

    // this() { ptr = buf.ptr; }

    // I want that data can be used only at block { that requested it }

    void[] data() @trusted return scope { 

        return ptr[0..10]; // returns some internals 

    }

}

​

// user func that work with Data internals that shouldn't run away

// user can forget to use "scope"

void[] userFunc( ref Data d ) @safe { 

    auto tmp = d.data;

    // FIXME 

    // tmp shouldn't run away. 

    // "scope" in user hands is not solution. (scope ref Data d)

    // lib should control access to lib internals not the user.

    return tmp; 

}

​

void main() {

    Data d;

    userFunc( d );

    "data runs away. and dip1000 is enabled.".writeln;

}

​