If ever you encounter error like this:
(159/159) checking for file conflicts [###################################################################] 100%
error: failed to commit transaction (conflicting files)
mingw-w64-i686-glib2: /mingw32/bin/gi-compile-repository.exe exists in filesystem
mingw-w64-i686-glib2: /mingw32/bin/gi-decompile-typelib.exe exists in filesystem
mingw-w64-i686-glib2: /mingw32/bin/gi-inspect-typelib.exe exists in filesystem
mingw-w64-i686-glib2: /mingw32/bin/libgirepository-2.0-0.dll exists in filesystem
...and so on...The use the following command to update your system:
pacman -Suuy --overwrite "*"