Is an automatic string variable a dynamic array in the sense of sec. 10.11.2 "Identity Expression" par. 4?

[Salih Dincer]

On Friday, 15 July 2022 at 13:34:03 UTC, kdevel wrote:
>
> In this piece of code [2]:
>
> ```
>    void main ()
>    {
>       string s = null;
>       string t = "";
>       assert (s is t);
>    }
> ```
>
> the assertion trips although both conditions of the given rule 
> are met.

```d
       string s, t;
void main()
{
       assert(s is t);
       assert(s is null);
       assert(t is null);

       s.length = 2;
       t.length = 2;

       assert(!is(s == t)); // true (check identy)
       assert(s == t); // true (check content)

       // because they are different strings:
       assert(is(string : typeof(s)));
       assert(is(string : typeof(t)));

       // but it can be same:
       auto u = s[0..2]; // a dynamic array

       assert(s is u); // true
       assert(s == u); // right on

       import std.stdio; // see following:
       writeln(cast(ubyte[])s); // [255, 255]
       writeln(cast(ubyte[])t); // [255, 255]
       writeln(cast(ubyte[])u); // [255, 255]
```

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