Debian Stretch and Ubuntu 18.04 (bionic) have come with vim 8.0, which breaks all sorts of things.
The following vimrc file seems to fix things
And then a couple of things I like
set tabstop=8 softtabstop=0 expandtab shiftwidth=4 smarttab
The first line has to source the default to enable things like syntax highlighting (which vanish if you just have a normal .vimrc