6 Basic concepts [basic]

typedef int  c;
enum { i = 1 };

class X {
  char  v[i];                       // error: i refers to ​::​i but when reevaluated is X​::​i
  int  f() { return sizeof(c); }    // OK: X​::​c
  char  c;
  enum { i = 2 };
};

typedef char*  T;
struct Y {
  T  a;                             // error: T refers to ​::​T but when reevaluated is Y​::​T
  typedef long  T;
  T  b;
};

typedef int I;
class D {
  typedef I I;                      // error, even though no reordering involved
};