gcc/testsuite/g++.dg/modules/tpl-friend-1_b.C

// { dg-additional-options -fmodules-ts }

module foo;

void foo (int x, void *p)
{
  auto *obj = reinterpret_cast<TPL<int> *> (p);

  obj->member = x;
}

void foo (float x, void *p)
{
  auto *obj = reinterpret_cast<TPL<float> *> (p);

  obj->member = x;
}