Description

Once an object has been validated, we can skip subsequent validations of the object (as its own type). This is true of sub-objects, too: within a ZWrapper, an already-validated object does not need to be validated again. This should save us lots of duplicate calculation.

Desired behavior/Acceptance criteria (returned value, expected error, performance expectations, etc.)

• add a marker to ZWrapper (e.g. alreadyValid)
• invalidate pre-validated ZWrappers whenever an internal object changes to an invalid state
• short-circuit validation (as self-declared type) upon encountering an alreadyValid object
• avoid validation as Z1 on alreadyValid objects (since, trivially, anything that validates as anything MUST also validate as Z1)

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Completion checklist

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