llvm-project/clang/test/Modules/cxx-linkage-cache.cpp

// RUN: rm -rf %t
// RUN: %clang_cc1 -x objective-c++ -fmodules -fimplicit-module-maps -fmodules-cache-path=%t -I %S/Inputs %s -verify -std=c++11

@import cxx_linkage_cache;

T x; // expected-error {{unknown type name 'T'}}
D::U<int> u;
bool b = f(u);