func bar() -> Foo<() throws -> Int> { let f: (@escaping (@escaping () throws -> Int) -> ()) -> () = { _ in } return foo(f) } この場合、二つ目の @escaping が足りてない？ (edited)func bar() -> Foo<() throws -> Int> { let f: (@escaping (@escaping () throws -> Int) -> ()) -> () = { _ in } return foo(f) } この場合、二つ目の @escaping が足りてない？ (edited)