🚀 go-pugleaf

In g++ 1.36.0- the attached programs gives the following error:
    In function int main ():
    mu.cc:24: request for member `a' is ambiguous
when in fact, the reference to the member is properly qualified.
No output file is produced.

Casting the object to (top_left) or (top_right) or (top) works,
and produces an output file, but generates the apparently spurious error message
    In function int main ():
    mu.cc:24: warning: assignment to virtual aggregate type


#include <stdio.h>

struct top {
  int a = 0;
  virtual int report() { return a; };
};

struct top_left : public top {
  int a = 1;
};

struct top_right : public top {
  int a = 2;
};

struct bottom : public top_left, public top_right {
  int b;
};

main()
{
  bottom x;
  
  printf("%d\n", x.a);
}