ConstraintTraitMask inconsistencies?

[Jon889]

While writing tests for them, I noticed that in this test:

 func testViewContraintsConstraintsWithMarginTraits() {
      let view = UIView()
      let superview = UIView()
      superview.addSubview(view)
      
      XCTAssertFalse(view.contains(trait: .TopMargin))
      let topConstraint = view.topAnchor.constraint(equalTo: superview.topAnchor, constant: 30)
      topConstraint.isActive = true
      XCTAssertEqual(view.constraints(forTrait: .VerticalMargins), [topConstraint])
      XCTAssertTrue(view.contains(trait: .VerticalMargins))
      
    }

The second assertion will fail, as the implementation of contains(trait:) checks if the array of traits contains the passed in trait, whereas the the constraints(forTrait:) function checks if the passed in trait contains each constraint-on-the-view's trait.

I'm not sure why the contains(trait:) implementation isn't just calling constraints(forTrait: trait) and checking if the result is empty. But it seems like they should be consistent.

I'd suggest just removing/deprecating these methods as this sort of method in UIKit is for debugging only, and it's always better to store the constraints in a variable if they are needed rather than access them this way.