llvm-project/clang/test/Modules/no-implicit-maps.cpp

// RUN: rm -rf %t
// RUN: %clang_cc1 -x objective-c -fno-modules-implicit-maps -fmodules-cache-path=%t -fmodules -I %S/Inputs/private %s -verify
@import libPrivate1;  // expected-error {{not found}}