Create a new channel as a copy of main.
Rename main to:
Delete main? This cannot be undone.
// RUN: %clang_cc1 %s -std=gnu89 -pedantic -fsyntax-only -verify int f(int restrict); void main(void) {} // expected-warning {{return type of 'main' is not 'int'}} expected-note {{change return type to 'int'}}