$cat full.swift extension Optional { @_specialize(exported: true, kind: full, where Wrapped == Int, S == [Int]) func foo<S : Sequence>(_ sequence: S) -> [Wrapped] where S.Element == Wrapped { return Array(sequence) + (self.map { [$0] } ?? []) } } let a: Int? = 7 let b: [Int] = [2, 3, 5] print(a.foo(b)) $cat partial.swift extension Optional { @_specialize(exported: true, kind: partial, where S == [Int]) func foo<S : Sequence>(_ sequence: S) -> [Wrapped] where S.Element == Wrapped { return Array(sequence) + (self.map { [$0] } ?? []) } } let a: Int? = 7 let b: [Int] = [2, 3, 5] print(a.foo(b)) $swift -O full.swift full.swift:2:60: warning: redundant same-type constraint 'Wrapped' == 'Int' @_specialize(exported: true, kind: full, where Wrapped == Int, S == [Int]) ^ full.swift:2:70: note: same-type constraint 'S.Element' == 'Int' implied here @_specialize(exported: true, kind: full, where Wrapped == Int, S == [Int]) ^ [2, 3, 5, 7] $swift -O partial.swift [2, 3, 5, 7] $md5 full MD5 (full) = 728efb9ffc6814bb17e0eedb72c5cda2 $md5 partial MD5 (partial) = c07fb4573afb1d8ae2ee53f30f341383 (edited)
