[Issue 18283] -dip1000 doesn't catch invalid local reference

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=18283

--- Comment #1 from Mike Franklin <slavo5150 at yahoo.com> ---
Interestingly, `destroy` is an unsafe operation for classes.

import std.stdio;

class A
{
    void hello() @safe { writeln("hello"); }
}

void main() @safe
{
    A a = new A();
    a.hello();
    destroy(a);  // onlineapp.d(12): Error: @safe function 'D main' cannot call
                 // @system function 'object.destroy!(A).destroy'
    a.hello();
}

https://run.dlang.io/is/AwKBc3


But it's not an unsafe operation for pointers

import std.stdio;

struct A
{
    int i;
    void print() @safe { writeln(i); }
}

void main() @safe
{
    A* a = new A();
    a.print();  // OK
    a.destroy();
    a.print();  // Error!
}

https://run.dlang.io/is/Fm7qBR



I'm not sure what the language authors' intentions are, so I can't say whether
the bug is in SafeD, or in the implementation of `destroy`.

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