W3TC breaks under WordPress 3.1 beta 1
See this note here: http://wordpress.org/news/2010/11/wordpress-3-1-beta-1/
Fatal error: Call to a member function is_page() on a non-object in /wp-includes/query.php. is_page() may be any conditional tag. This issue occurs when a theme or plugin is doing something wrong. Some code is checking the value of a conditional tag before we actually set up the Query, which means they don’t work yet. In 3.0, they silently failed and always returned false. In 3.1 Beta 1, this is throwing a fatal error. This will be handled in the final release, so use this opportunity to fix your plugins.
I am seeing on my 3.1 installation:
Fatal error: Call to a member function is_feed() on a non-object in /home/fv/public_html/wp-includes/query.php on line 318
Which was called from:
is_feed( ) ../Minify.php:807