Nyall Dawson a8110369a8 [processing] Don't throw an exception if an expression cannot
be prepared

There's cases where this happens without reflecting an invalid
expression. So we can try to prepare, but not abort if the
preparation fails.

Fixes #18103
2018-02-15 15:43:26 +11:00
..
2018-02-06 19:25:48 +02:00
2016-11-12 13:31:44 +02:00