swift

e7f82bc6 - [ConstraintSystem] Record both the UUID and the shape class for opened pack

[ConstraintSystem] Record both the UUID and the shape class for opened pack element environments. This allows the constraint system to ensure that for a given pack expansion locator, the given shape class is always the same when requesting the element environment. If the shape class differs, it means there's a same-shape requirement failure, which will be diagnosed via the ShapeOf constraint simplification.