$ sudo pacman -U swift-bin-3.1-1-x86_64.pkg.tar.xz
loading packages...
resolving dependencies...
looking for conflicting packages...

Packages (1) swift-bin-3.1-1

Total Installed Size:  376.52 MiB
Net Upgrade Size:       10.88 MiB

:: Proceed with installation? [Y/n]
(1/1) checking keys in keyring                     [######################] 100%
(1/1) checking package integrity                   [######################] 100%
(1/1) loading package files                        [######################] 100%
(1/1) checking for file conflicts                  [######################] 100%
error: failed to commit transaction (conflicting files)
swift-bin: /usr/lib/python2.7/site-packages/six.pyc exists in filesystem
Errors occurred, no packages were upgraded.