This one requires two files.  One defines a private
global symbol that is used in a template.  The
other file uses the template.  Here is the error:

C:\Programming\D\bugs\err10>dmd inc.d err.d
c:\Programming\tools\dmd\bin\..\..\dm\bin\link.exe
inc+err,,,user32+kernel32/noi;
OPTLINK (R) for Win32  Release 7.50B1
Copyright (C) Digital Mars 1989 - 2001  All Rights Reserved

err.obj(err)
Error 42: Symbol Undefined _D3inc3fooi
--- errorlevel 1

Here are the two files:

// inc.d
private int foo;

template Func()
{
void Func(int bar)
{
foo = bar;
}
}

// err.d
import inc;

int main(char[][] a)
{
Func!()(2);

return 0;
}