opIndexUnary post in-/decrement how to ?

[Ali Çehreli]

On 7/14/21 11:27 AM, Tejas wrote:

 > the compiler error should have been a dead giveaway
 > that opIndex was returning a _constant_ value

I know you mean "rvalue" but if I may be unnecessarily pedantic, an 
rvalue can indeed be mutated:

struct A {
   int i;
   void mutate() {
     i = 42;
     import std.stdio;
     writeln("I am not constant. :)");
   }
}

struct B {
   auto opUnary(string op)() {
     return A();
   }
}

void main() {
   auto b = B();
   (++b).mutate();  // <-- Mutating an rvalue
}

Ali