-R/--restow option has no obvious effect under macOS build of stow 2.2.2.

To reproduce the bug, I am using macOS 10.12.6.  After installing the
software from brew, I executed the following:

mkdir -p tmp/stow/abc-1
mkdir -p tmp/stow/abc-2
echo "DEF 1" > tmp/stow/abc-1/def.txt
echo "DEF 2" > tmp/stow/abc-2/def.txt
cd tmp/stow
stow abc-1
cat ../def.txt   # yields DEF 1, as expected.
stow abc-2   # fails, as expected.
stow -R abc-2   # fails in exactly the same way as above, NOT expected.
stow -D abc-1   # But this works...
stow abc-2
cat ../def.txt   # Yields DEF 2, as desired.

Available documentation suggests that stow -R P is equivalent to stow
-D P && stow -S P.  Here's the relevant command-line transcript:

falvosa-mbp:stow falvosa$ stow abc-2
WARNING! stowing abc-2 would cause conflicts:
  * existing target is stowed to a different package: def.txt =>
stow/abc-1/def.txt
All operations aborted.
falvosa-mbp:stow falvosa$ stow -R abc-2
WARNING! stowing abc-2 would cause conflicts:
  * existing target is stowed to a different package: def.txt =>
stow/abc-1/def.txt
All operations aborted.
falvosa-mbp:stow falvosa$ stow -D abc-1
falvosa-mbp:stow falvosa$ stow abc-2
falvosa-mbp:stow falvosa$ _

If there's anything else I need to provide with my bug report, please
let me know.  Thanks!!

-- 
Samuel A. Falvo II