If a struct defines both (1) a destructor and (2) a postblit or copy constructor, assigning it as a value to a slice will produce an invalid result:

```
import std.stdio;

struct Uncopiable {
    int value;
    
    ~this() {
    }
    
    @disable this(const ref Uncopiable);
    
}

void testCopy(Uncopiable unc) {}

void main() {
    
    auto a = Uncopiable(1);
    auto b = Uncopiable(2);    
    //testCopy(a);  // fails, alright
    
    auto c = [Uncopiable(3)];
    c[] = a;   
    writeln(c[0].value);  // Prints 3 instead of 1
    writeln(a.value); // Prints 3 instead of 1
}
```

Removing either the destructor or copy constructor fixes the above problem. The issue also occurs if the copy constructor is replaced with a postblit.

The bug appears to have been introduced in #14382 
https://github.com/dlang/dmd/commit/d0a367e98cc31a2675a5fc41a150dd38089f1982#diff-c9a721f453e1e17d997f8603ca3e4e65c765f0ebf0dd1cfb972ddddc959bdbb1