The filetype needs to be set during BufRead in order for the did_filetype() check to prevent the file being detected as a conf file. One example where this can occur is if a cgo file has a #include at the top of the file. The # is detected in vim's generic configuration (conf file) toward the bottom of filetype.vim
R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/5496066
This sets up vim to work out of the box with go programs as long as syntax
highlighting is enabled. Both files must be copied to the vim runtime
directory in order for the file-type detection and syntax loading to work.
R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/1723044