Validation rules completion work in Form Request classes and in validate calls:
Fields:
Request validation rules often contains fields for some Eloquent model. Laravel Idea provides a quick way to add these fields automatically. This works only if Eloquent Helper code was generated before. Cmd-N or Alt-Insert inside any validation array:
Validation rules completion can be configured in the settings Preferences | Languages & Frameworks | Laravel Idea | Validation:
For example, if you want to complete validation rules for $validation
field of every child class of \VendorName\VendorAction
class just add "VendorAction" to "Rule completion base class names" and "validation" to "Rule completion field names". Result: