https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91748

            Bug ID: 91748
           Summary: doesn't compile std::for_each_n for random access
                    iterator range
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: faithandbrave at gmail dot com
  Target Milestone: ---

#include <algorithm>

int main() {
  int ar[] = {1, 2, 3};
  std::for_each_n(ar, 3, [](int) {});
}

doesn't compile the code. compilation error is follow:
In file included from /opt/wandbox/gcc-head/include/c++/10.0.0/algorithm:62,
                 from prog.cc:1:
/opt/wandbox/gcc-head/include/c++/10.0.0/bits/stl_algo.h: In instantiation of
'_InputIterator std::for_each_n(_InputIterator, _Size, _Function) [with
_InputIterator = int*; _Size = int; _Function = main()::<lambda(int)>]':
prog.cc:5:36:   required from here
/opt/wandbox/gcc-head/include/c++/10.0.0/bits/stl_algo.h:3996:22: error: cannot
convert 'main()::<lambda(int)>' to 'int*' in return
 3996 |  return std::for_each(__first, __first + __n2, __f);
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      |                      |
      |                      main()::<lambda(int)>

It seems mistake return type. The function should returns iterator, but the
function returns function object.
https://github.com/gcc-mirror/gcc/blob/b8f684bc811e410d9cd82de83e8e6d4cc15dca8c/libstdc%2B%2B-v3/include/bits/stl_algo.h#L3996

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