Create a new channel as a copy of main.
Rename main to:
Delete main? This cannot be undone.
; RUN: echo save > %t.mri ; RUN: echo create %t.a >> %t.mri ; RUN: echo end >> %t.mri ; RUN: not llvm-ar -M < %t.mri 2>&1 | FileCheck %s ; CHECK: error: script line 2: file already saved