As an editor I want to see constraints violations on Form statements in order to see mistakes in the data and fix them.
Right now statements on the Form (and Sense) level are not checked for constraints violations.
https://www.wikidata.org/wiki/Lexeme:L123 has two "compound of" statements at the moment. The one on the Lexeme level shows a constraint violation because of a missing mandatory qualifier. The one on the Form level doesn't.
GIVEN a statement on a Form
AND that statement violates a constraint
WHEN loading the Lexeme page
THEN the violation should be checked and indicated via the little constraint violation icon
* statements on Forms are checked for constraint violations and indicate them to the user in the same way as constraint violations on Item or Lexeme-level statements
* Should `action=wbcheckconstraints&id=L1` automatically check constraints on `L1`’s forms and senses, or should the gadget add the IDs of all the forms and senses to the API request?