Create a new channel as a copy of main.
Rename main to:
Delete main? This cannot be undone.
// RUN: %clang_cc1 %s -emit-llvm -std=c++11 -o %t struct A { ~A(); }; struct B { A a; }; struct C { union { B b; }; ~C() noexcept; }; C::~C() noexcept {}