Annoying highlighting bug

The following regex: [^\w\.](tango|core|std)\.[\w\.]+ 
was causing the character right before std., core., and tango. to be highlighted too.  This also caused problems with comments.  
For example, algorithm.d looked like over half of it was commented out. Removing [^\w\.] seemed to resolve this issue, and doesn't look like it broke anything else.
Here is an excerpt from the new std.process (line 1376) which also showed the problem:
assert (environment.get("std.process") == null); 
This also made it look like the rest of the file was commented out.