Implementation of invoke_result<t_FN, t_ARGTYPES...>. This specialization is instantiated in C++11 and later when t_FN is a pointer-to-member-function type, and the t_ARGTYPES... pack is empty. Note that this struct does not provide a type typedef.
Declared in <bslmf_invokeresult.h>
template<class t_FN>
struct InvokeResult_MemFuncPtrImp<t_FN>;