| // RUN: rm -rf %t | 
 | // RUN: rm -rf %t-saved | 
 | // RUN: mkdir %t-saved | 
 |  | 
 | // Initial module build | 
 | // RUN: %clang_cc1 -fmodules -fimplicit-module-maps -fbuiltin-headers-in-system-modules \ | 
 | // RUN:     -fmodules-cache-path=%t -fdisable-module-hash -isystem %S/Inputs/System/usr/include \ | 
 | // RUN:     -fsyntax-only %s -verify | 
 | // RUN: cp %t/cstd.pcm %t-saved/cstd.pcm | 
 |  | 
 | // Even with -Werror don't rebuild a system module | 
 | // RUN: %clang_cc1 -fmodules -fimplicit-module-maps -fbuiltin-headers-in-system-modules \ | 
 | // RUN:     -fmodules-cache-path=%t -fdisable-module-hash -isystem %S/Inputs/System/usr/include \ | 
 | // RUN:     -fsyntax-only %s -verify -Werror | 
 | // RUN: diff %t/cstd.pcm %t-saved/cstd.pcm | 
 |  | 
 | // Unless -Wsystem-headers is on | 
 | // RUN: %clang_cc1 -fmodules -fimplicit-module-maps -fbuiltin-headers-in-system-modules \ | 
 | // RUN:     -fmodules-cache-path=%t -fdisable-module-hash -isystem %S/Inputs/System/usr/include \ | 
 | // RUN:     -fsyntax-only %s -verify -Werror=unused -Wsystem-headers | 
 | // RUN: not diff %t/cstd.pcm %t-saved/cstd.pcm | 
 |  | 
 | // expected-no-diagnostics | 
 | @import cstd; |