symfony/symfony-docs — pull request #4086 by peterrehm (2014-08-04 11:31:13+00:00)
Title: [Reference][Constraints] Added hint about attaching the expression constraint to a form field

| Q | A
| ------------- | ---
| Doc fix? | yes
| New docs? | no
| Applies to | 2.4
| Fixed tickets | -

As per my discussion with @webmozart a while ago on twitter https://twitter.com/peterrehm/status/434350363940904960 I am now providing the hint about the possibility to add a expression constraint to a form field.