Returning reference: why this works?

[Denis Feklushkin]

import std.stdio;

struct S { int x; }

ref S func1(ref S i) // i is reference
{
     return i;
}

ref S func2(S i) // i is not reference
{
   return func1(i); // Works! Possibility to return reference to 
local object i?
   //return i; // Error: returning i escapes a reference to 
parameter i
}

void main() {
   auto ret = func2(S(2));

   writeln(ret); // "S(2)"
}