On Saturday, 30 July 2022 at 10:34:09 UTC, ag0aep6g wrote:

You're right! I saw the hole at the end of the tunnel late 😀

But if you compile the example below without the new operator, the system does not work and does not give any errors. Why?

Voldermort Type Version:

auto imstr(string str) pure @safe
{
  struct IMSTR
  {
    string s;
    void delegate(string s) @safe update;
    string toString() const { return s; }
  }
  auto s = new IMSTR(str);
       s.update = (_) { s.s = _; };
  return s;
}

import std.stdio;
void main() @safe
{
  immutable auto str = imstr("Test 123");
  //str.s = "test";

  str.toString.writeln;
  str.update("TEST A");

  str.toString.writeln;
  str.update("TEST B");

  str.toString.writeln;
  typeid(str).writeln;

}/* Prints:
Test 123
TEST A
TEST B
immutable(immutable(onlineapp.imstr(immutable(char)[]).IMSTR)*)
*/

SDB@79