What steps will reproduce the problem?
1. Put the jq.js file in a temporary directory (say in ~/tmp/jq/jq.js).
2. cd to ~/tmp/jq/ .
3. Invoke gvim.
3. Type «:grep -r URI .»
4. Type :cn

What is the expected output? What do you see instead?

gvim tries to edit a new file with an unmanagable name instead of keep editing 
the very long line of jq.js. 

What version of the product are you using? On what operating system?

gvim-7.3.237 on Mageia Linux Cauldron x86-32.

Please provide any additional information below.

It also happens on Mandriva Linux Cooker on x86-64 with gvim-7.3.2xx mhi^ from 
IRC verified it to happen to.