Lemme guess, untested code? :-)

I wrote the same thing, tried it with his test and realized that he differentiated between scalar and void context. FWIW my first try involved:

push my @result, wantarray ? &inner_func() : scalar &inner_func();
[download]

then I realized the problem, and came up with:

sub outer_func {
  my @result;
  defined(wantarray) ?
   (push @result, wantarray ? &inner_func() : scalar &inner_func())
   : &inner_func();
  # do some other stuff
  return (wantarray ? (@result) : $result[0]);
}
[download]

Ick. :-( There are times you should be verbose. This is one of them...

Personally I think your approach of separating the cases is cleaner. But honestly I have never once encountered a situation where I needed to propagate context in this manner...