Create a new channel as a copy of main.
Rename main to:
Delete main? This cannot be undone.
// RUN: %clang_cc1 -std=c++20 %s -triple %itanium_abi_triple -emit-llvm -o - | FileCheck %s export module Foo:impl; // CHECK-DAG: @_ZW3Foo4Quuxv( export void Quux() { }