7 Standard conversions [conv]

7.13 Function pointer conversions [conv.fctptr]

1
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A prvalue of type “pointer to noexcept function” can be converted to a prvalue of type “pointer to function”.
The result is a pointer to the function.
A prvalue of type “pointer to member of type noexcept function” can be converted to a prvalue of type “pointer to member of type function”.
The result points to the member function.
[ Example
: 
  void (*p)();
  void (**pp)() noexcept = &p;  // error: cannot convert to pointer to noexcept function

  struct S { typedef void (*p)(); operator p(); };
  void (*q)() noexcept = S();   // error: cannot convert to pointer to noexcept function
— end example
 ]