Hi all,

Setting comment-continue to "  " breaks the logic of uncomment-region-default, causing it to get into an infinite loop (repeatedly matching an empty string at the same location).
uncomment-region-default is used by comment-line (C-x C-;).

Setting comment-continue to "  " could be a mistake, in which case this bug is a request to document the limitation :) Or it may be a valid value, in which case uncomment-region-default is broken.

The original context was comments like in a major mode that I'm writing, for which setting comment-continue to "  " seem(s/ed) reasonable.

/* AAA
   BBB
   CCC */

Cheers,
Clément.