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void baz();
void baz(int);
 
template<typename... Args, typename R>
void bar(R (*)(Args...));
 
template<typename... Args>
void foo()
{
	bar<Args...>(baz);
}
 
int main()
{
	foo<>();		  // Deduces baz()
	bar<>(baz);	  // Ambiguous
	foo<int>();		  // Deduces baz(int)
	bar<int>(baz);	  // Deduces baz(int)
	//foo<void>();	  // Ambiguous
	//bar<void>(baz); // Ambiguous
}
 

prog.cpp: In function 'int main()':
prog.cpp:16:11: error: no matching function for call to 'bar(<unresolved overloaded function type>)'
  bar<>(baz);   // Ambiguous
           ^
prog.cpp:5:6: note: candidate: template<class ... Args, class R> void bar(R (*)(Args ...))
 void bar(R (*)(Args...));
      ^
prog.cpp:5:6: note:   template argument deduction/substitution failed:
prog.cpp:16:11: note:   couldn't deduce template parameter 'R'
  bar<>(baz);   // Ambiguous
           ^

Standard output is empty