llvm/clang/test/Modules/modulemaps-nomodules.cpp

// Make sure we treat includes that are part of modulemaps the same as textual
// headers when modules are not enabled (e.g do't generate import decls, but
// still perform layering checks).
// No need to pass -fno-modules explicitly, absence implies negation for cc1.
// RUN: %clang_cc1 -I %S/Inputs/modulemaps-nomodules -fmodule-map-file=%S/Inputs/modulemaps-nomodules/module.modulemap %s -verify -ast-dump | FileCheck %s

#include "header.h" // expected-error{{use of private header from outside its module: 'header.h'}}
// CHECK-NOT: ImportDecl