Fork channel

Create a new channel as a copy of main.

Rename channel

Rename main to:

Delete channel

Delete main? This cannot be undone.

PR6618.cpp
// RUN: %clang_cc1 -fsyntax-only -verify %s
class bar; // expected-note {{forward declaration of 'bar'}}
struct zed {
  bar g; // expected-error {{field has incomplete type}}
};
class baz {
  zed h;
};
void f() {
  enum {
    e = sizeof(baz)
  };
}