A result type with a literal discriminant, and every branch typed without a single assertion. The discriminant has to be a literal type on every member, and a…
A value object rejecting an invalid input with a message that named the type rather than the problem. One check per condition and a named constructor per failure…
An enum implementing both a presentation interface and a domain one, which is two responsibilities agreeing to share a file. The test that settled it was asking which…