protocol Foo {} extension Int: Foo {} protocol P { associatedtype F: Foo func foo1() -> F func foo2() -> F } struct S: P { func foo1() -> __opaque Foo { return 2 } func foo2() -> __opaque Foo { return 3 } } let s = S() var a = s.foo1() let b = s.foo2() a = b
/path/to/opaque-result.swift:9:8: error: type 'S' does not conform to protocol 'P' struct S: P { ^ /path/to/opaque-result.swift:5:20: note: ambiguous inference of associated type 'F': '(__opaque main.(file).S.foo2()@/path/to/opaque-result.swift:11:10)' vs. '(__opaque main.(file).S.foo1()@/path/to/opaque-result.swift:10:10)' associatedtype F: Foo ^ /path/to/opaque-result.swift:11:10: note: matching requirement 'foo2()' to this declaration inferred associated type to '(__opaque main.(file).S.foo2()@/path/to/opaque-result.swift:11:10)' func foo2() -> __opaque Foo { return 3 } ^ /path/to/opaque-result.swift:10:10: note: matching requirement 'foo1()' to this declaration inferred associated type to '(__opaque main.(file).S.foo1()@/path/to/opaque-result.swift:10:10)' func foo1() -> __opaque Foo { return 2 } ^ /path/to/opaque-result.swift:17:5: error: cannot assign value of type '(__opaque main.(file).S.foo2()@/path/to/opaque-result.swift:11:10)' to type '(__opaque main.(file).S.foo1()@/path/to/opaque-result.swift:10:10)' a = b ^ as! (__opaque main.(file).S.foo1()@/path/to/opaque-result.swift:10:10)
