false true true falsestderr:

<stdin>:5:14: warning: 'is' test is always true print(P.self is P.Protocol) ^ <stdin>:6:16: warning: 'is' test is always true print(Int.self is P.Type) ^ <stdin>:7:16: warning: cast from 'Int.Type' to unrelated type 'P.Protocol' always fails print(Int.self is P.Protocol) ~~~~~~~~ ^ ~~~~~~~~~~

(edited)