runt! html.vim may break other behavior

[12425]

It is not safe to source html.vim for other file types.

For example,
In my ftplugin/ I have html.vim and xml.vim
html.vim:
map a b
xml.vim:
map a c
Without MatchTag, I can get right mapping (a->c) in xml, however with MatchTag, I get a->b for xml files, because html.vim is loaded after xml.vim.

We may have 2 solutions:

1. use so <sfile>:p:h/html.vim instead of runtime in other file types.
2. wrap everything in html.vim into a function and define autocmd in plugin/.

Thanks.