Metal Shader C++ Templates

So in C++ the following compiles:

// foo.hpp

template <typename T> T foo(T bar);

// foo.cpp

#include "foo.hpp"

template <typename T> T foo(T bar)
{
  bar++;
  return bar;
}

template char foo(char bar);

// main.cpp

#include "foo.hpp"

extern template char foo(char bar);

char Cplusplus()
{
  return foo('C');
}


int main() {}

If I copy all code except main() into a Metal shader library with foo.hpp, foo.metal and main.metal and try to compile, then at the linking step I get the following:

metallib: multiple symbols ('_Z3fooIcET_S0_') with incompatible linkages!

Is there any way to use templates in Metal that doesn't involve any code duplication? (i.e. defining templates in headers, trivial specializations, etc)