gcc/testsuite/g++.dg/modules/adl-4_a.C

// { dg-additional-options -fmodules-ts }
export module inter;
// { dg-module-cmi inter }

namespace hidden {
// not found via ADL
int fn (int x);

}

export template <typename T>
int TPL (T &t)
{
  return fn (t);
}