Files
swift-mirror/test/Constraints/generics.swift
Henrik G. Olsson d3214de950 Merge pull request #84685 from hnrklssn/verify-all
This adds the -verify-ignore-unrelated flag. When -verify is used without -verify-ignore-unrelated, diagnostics emitted in buffers other than the main file and those passed with -verify-additional-file (except diagnostics emitted at <unknown>:0) will now result in an error. They were previously ignored. The old behaviour is still available as opt-in using -verify-ignore-unrelated, but by being strict by default it should make it harder to accidentally miss diagnostics.

To avoid unnecessary performance overhead, -verify-additional-file is still required to parse the expected-* directives in files other than the main file.
2025-10-06 18:01:47 -07:00

1133 lines
44 KiB
Swift

// RUN: %target-typecheck-verify-swift -verify-ignore-unrelated -enable-objc-interop
infix operator +++
protocol ConcatToAnything { // expected-note {{where 'Self' = 'U'}}
static func +++ <T>(lhs: Self, other: T)
}
func min<T : Comparable>(_ x: T, y: T) -> T {
if y < x { return y }
return x
}
func weirdConcat<T : ConcatToAnything, U>(_ t: T, u: U) {
t +++ u
t +++ 1
u +++ t // expected-error{{referencing operator function '+++' on 'ConcatToAnything' requires that 'U' conform to 'ConcatToAnything'}}
}
// Make sure that the protocol operators don't get in the way.
var b1, b2 : Bool
_ = b1 != b2
extension UnicodeScalar {
func isAlpha2() -> Bool {
return (self >= "A" && self <= "Z") || (self >= "a" && self <= "z")
}
}
protocol P {
static func foo(_ arg: Self) -> Self
}
struct S : P {
static func foo(_ arg: S) -> S {
return arg
}
}
func foo<T : P>(_ arg: T) -> T {
return T.foo(arg)
}
// Associated types and metatypes
protocol SomeProtocol {
associatedtype SomeAssociated
}
func generic_metatypes<T : SomeProtocol>(_ x: T)
-> (T.Type, T.SomeAssociated.Type)
{
return (type(of: x), type(of: x).SomeAssociated.self)
}
// Inferring a variable's type from a call to a generic.
struct Pair<T, U> { } // expected-note 3 {{'T' declared as parameter to type 'Pair'}} expected-note 3 {{'U' declared as parameter to type 'Pair'}}
func pair<T, U>(_ x: T, _ y: U) -> Pair<T, U> { }
var i : Int, f : Float
var p = pair(i, f)
// Conformance constraints on static variables.
func f1<S1 : Sequence>(_ s1: S1) {}
var x : Array<Int> = [1]
f1(x)
// Inheritance involving generics and non-generics.
class X {
func f() {}
}
class Foo<T> : X {
func g() { }
}
class Y<U> : Foo<Int> {
}
func genericAndNongenericBases(_ x: Foo<Int>, y: Y<()>) {
x.f()
y.f()
y.g()
}
func genericAndNongenericBasesTypeParameter<T : Y<()>>(_ t: T) {
t.f()
t.g()
}
protocol P1 {}
protocol P2 {}
func foo<T : P1>(_ t: T) -> P2 {
return t // expected-error{{return expression of type 'T' does not conform to 'P2'}}
}
func foo2(_ p1: P1) -> P2 {
return p1 // expected-error{{return expression of type 'any P1' does not conform to 'P2'}}
}
// <rdar://problem/14005696>
protocol BinaryMethodWorkaround {
associatedtype MySelf
}
protocol Squigglable : BinaryMethodWorkaround {
}
infix operator ~~~
func ~~~ <T : Squigglable>(lhs: T, rhs: T) -> Bool where T.MySelf == T {
return true
}
extension UInt8 : Squigglable {
typealias MySelf = UInt8
}
var rdar14005696 : UInt8
_ = rdar14005696 ~~~ 5
// <rdar://problem/15168483>
public struct SomeIterator<C: Collection, Indices: Sequence>
: IteratorProtocol, Sequence
where C.Index == Indices.Iterator.Element {
var seq : C
var indices : Indices.Iterator
public typealias Element = C.Iterator.Element
public mutating func next() -> Element? {
fatalError()
}
public init(elements: C, indices: Indices) {
fatalError()
}
}
func f1<T>(seq: Array<T>) {
let x = (seq.indices).lazy.reversed()
SomeIterator(elements: seq, indices: x) // expected-warning{{unused}}
SomeIterator(elements: seq, indices: seq.indices.reversed()) // expected-warning{{unused}}
}
// <rdar://problem/16078944>
func count16078944<T>(_ x: Range<T>) -> Int { return 0 }
func test16078944 <T: Comparable>(lhs: T, args: T) -> Int {
return count16078944(lhs..<args) // don't crash
}
// <rdar://problem/22409190> QoI: Passing unsigned integer to ManagedBuffer elements.destroy()
class r22409190ManagedBuffer<Value, Element> {
final var value: Value { get {} set {}}
func withUnsafeMutablePointerToElements<R>(
_ body: (UnsafeMutablePointer<Element>) -> R) -> R {
}
}
class MyArrayBuffer<Element>: r22409190ManagedBuffer<UInt, Element> {
deinit {
self.withUnsafeMutablePointerToElements { elems -> Void in
elems.deinitialize(count: self.value) // expected-error {{cannot convert value of type 'UInt' to expected argument type 'Int'}}
}
}
}
// <rdar://problem/22459135> error: 'print' is unavailable: Please wrap your tuple argument in parentheses: 'print((...))'
func r22459135() {
func h<S : Sequence>(_ sequence: S) -> S.Iterator.Element
where S.Iterator.Element : FixedWidthInteger {
return 0
}
func g(_ x: Any) {}
func f(_ x: Int) {
g(h([3]))
}
func f2<TargetType: AnyObject>(_ target: TargetType, handler: @escaping (TargetType) -> ()) {
let _: (AnyObject) -> () = { internalTarget in
handler(internalTarget as! TargetType)
}
}
}
// <rdar://problem/19710848> QoI: Friendlier error message for "[] as Set"
// <rdar://problem/22326930> QoI: "argument for generic parameter 'Element' could not be inferred" lacks context
_ = [] as Set // expected-error {{type 'Any' cannot conform to 'Hashable'}} expected-note {{only concrete types such as structs, enums and classes can conform to protocols}}
// expected-note@-1 {{required by generic struct 'Set' where 'Element' = 'Any'}}
//<rdar://problem/22509125> QoI: Error when unable to infer generic archetype lacks greatness
func r22509125<T>(_ a : T?) { // expected-note {{in call to function 'r22509125'}}
r22509125(nil) // expected-error {{generic parameter 'T' could not be inferred}}
}
// <rdar://problem/24267414> QoI: error: cannot convert value of type 'Int' to specified type 'Int'
struct R24267414<T> { // expected-note {{'T' declared as parameter to type 'R24267414'}}
static func foo() -> Int {}
}
var _ : Int = R24267414.foo() // expected-error {{generic parameter 'T' could not be inferred}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{24-24=<Any>}}
// https://github.com/apple/swift/issues/43216
func f_43216<T: FixedWidthInteger>() -> T.Type { return T.self } // expected-note {{in call to function 'f_43216()'}}
_ = f_43216() // expected-error {{generic parameter 'T' could not be inferred}}
// <rdar://problem/19215114> QoI: Poor diagnostic when we are unable to infer type
protocol Q19215114 {}
protocol P19215114 {}
// expected-note @+1 {{in call to function 'body9215114'}}
func body9215114<T: P19215114, U: Q19215114>(_ t: T) -> (_ u: U) -> () {}
func test9215114<T: P19215114, U: Q19215114>(_ t: T) -> (U) -> () {
let f = body9215114(t) // expected-error {{generic parameter 'U' could not be inferred}}
return f
}
// <rdar://problem/21718970> QoI: [uninferred generic param] cannot invoke 'foo' with an argument list of type '(Int)'
class Whatever<A: Numeric, B: Numeric> { // expected-note 2 {{'A' declared as parameter to type 'Whatever'}} expected-note {{'B' declared as parameter to type 'Whatever'}}
static func foo(a: B) {}
static func bar() {}
}
Whatever.foo(a: 23) // expected-error {{generic parameter 'A' could not be inferred}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{9-9=<<#A: Numeric#>, Int>}}
// <rdar://problem/21718955> Swift useless error: cannot invoke 'foo' with no arguments
Whatever.bar() // expected-error {{generic parameter 'A' could not be inferred}} expected-note 1 {{explicitly specify the generic arguments to fix this issue}} {{9-9=<<#A: Numeric#>, <#B: Numeric#>>}}
// expected-error@-1 {{generic parameter 'B' could not be inferred}}
// <rdar://problem/27515965> Type checker doesn't enforce same-type constraint if associated type is Any
protocol P27515965 {
associatedtype R
func f() -> R
}
struct S27515965 : P27515965 {
func f() -> Any { return self }
}
struct V27515965 {
init<T : P27515965>(_ tp: T) where T.R == Float {}
// expected-note@-1 {{where 'T.R' = 'Any'}}
}
func test(x: S27515965) -> V27515965 {
return V27515965(x)
// expected-error@-1 {{initializer 'init(_:)' requires the types 'Any' and 'Float' be equivalent}}
}
protocol BaseProto {}
protocol SubProto: BaseProto {}
@objc protocol NSCopyish {
func copy() -> Any
}
struct FullyGeneric<Foo> {} // expected-note 13 {{'Foo' declared as parameter to type 'FullyGeneric'}} expected-note 1 {{generic struct 'FullyGeneric' declared here}}
struct AnyClassBound<Foo: AnyObject> {} // expected-note {{'Foo' declared as parameter to type 'AnyClassBound'}} expected-note {{generic struct 'AnyClassBound' declared here}}
// expected-note@-1{{requirement specified as 'Foo' : 'AnyObject'}}
struct AnyClassBound2<Foo> where Foo: AnyObject {} // expected-note {{'Foo' declared as parameter to type 'AnyClassBound2'}}
// expected-note@-1{{requirement specified as 'Foo' : 'AnyObject' [with Foo = Any]}}
struct ProtoBound<Foo: SubProto> {} // expected-note {{'Foo' declared as parameter to type 'ProtoBound'}} expected-note {{generic struct 'ProtoBound' declared here}}
struct ProtoBound2<Foo> where Foo: SubProto {} // expected-note {{'Foo' declared as parameter to type 'ProtoBound2'}}
struct ObjCProtoBound<Foo: NSCopyish> {} // expected-note {{'Foo' declared as parameter to type 'ObjCProtoBound'}} expected-note {{generic struct 'ObjCProtoBound' declared here}}
struct ObjCProtoBound2<Foo> where Foo: NSCopyish {} // expected-note {{'Foo' declared as parameter to type 'ObjCProtoBound2'}}
struct ClassBound<Foo: X> {} // expected-note {{generic struct 'ClassBound' declared here}}
struct ClassBound2<Foo> where Foo: X {} // expected-note {{generic struct 'ClassBound2' declared here}}
struct ProtosBound<Foo> where Foo: SubProto & NSCopyish {} // expected-note {{'Foo' declared as parameter to type 'ProtosBound'}} expected-note {{generic struct 'ProtosBound' declared here}}
struct ProtosBound2<Foo: SubProto & NSCopyish> {} // expected-note {{'Foo' declared as parameter to type 'ProtosBound2'}}
struct ProtosBound3<Foo: SubProto> where Foo: NSCopyish {} // expected-note {{'Foo' declared as parameter to type 'ProtosBound3'}}
struct AnyClassAndProtoBound<Foo> where Foo: AnyObject, Foo: SubProto {} // expected-note {{'Foo' declared as parameter to type 'AnyClassAndProtoBound'}}
struct AnyClassAndProtoBound2<Foo> where Foo: SubProto, Foo: AnyObject {} // expected-note {{'Foo' declared as parameter to type 'AnyClassAndProtoBound2'}}
struct ClassAndProtoBound<Foo> where Foo: X, Foo: SubProto {} // expected-note {{where 'Foo' = 'X'}}
struct ClassAndProtosBound<Foo> where Foo: X, Foo: SubProto, Foo: NSCopyish {} // expected-note 2 {{where 'Foo' = 'X'}}
struct ClassAndProtosBound2<Foo> where Foo: X, Foo: SubProto & NSCopyish {} // expected-note 2 {{where 'Foo' = 'X'}}
extension Pair {
init(first: T) {}
init(second: U) {}
var first: T { fatalError() }
var second: U { fatalError() }
}
func testFixIts() {
_ = FullyGeneric() // expected-error {{generic parameter 'Foo' could not be inferred}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{19-19=<Any>}}
_ = FullyGeneric<Any>()
_ = AnyClassBound() // expected-error {{generic parameter 'Foo' could not be inferred}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{20-20=<AnyObject>}}
_ = AnyClassBound<Any>() // expected-error {{'AnyClassBound' requires that 'Any' be a class type}}
_ = AnyClassBound<AnyObject>()
_ = AnyClassBound2() // expected-error {{generic parameter 'Foo' could not be inferred}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{21-21=<AnyObject>}}
_ = AnyClassBound2<Any>() // expected-error {{'AnyClassBound2' requires that 'Any' be a class type}}
_ = AnyClassBound2<AnyObject>()
_ = ProtoBound() // expected-error {{generic parameter 'Foo' could not be inferred}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{17-17=<<#Foo: SubProto#>>}}
_ = ProtoBound<Any>() // expected-error {{type 'Any' does not conform to protocol 'SubProto'}}
_ = ProtoBound2() // expected-error {{generic parameter 'Foo' could not be inferred}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{18-18=<<#Foo: SubProto#>>}}
_ = ProtoBound2<Any>() // expected-error {{type 'Any' does not conform to protocol 'SubProto'}}
_ = ObjCProtoBound() // expected-error {{generic parameter 'Foo' could not be inferred}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{21-21=<NSCopyish>}}
_ = ObjCProtoBound<AnyObject>() // expected-error {{type 'AnyObject' does not conform to protocol 'NSCopyish'}}
_ = ObjCProtoBound<NSCopyish>()
_ = ObjCProtoBound2() // expected-error {{generic parameter 'Foo' could not be inferred}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{22-22=<NSCopyish>}}
_ = ObjCProtoBound2<AnyObject>() // expected-error {{type 'AnyObject' does not conform to protocol 'NSCopyish'}}
_ = ObjCProtoBound2<NSCopyish>()
_ = ProtosBound() // expected-error {{generic parameter 'Foo' could not be inferred}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{18-18=<<#Foo: NSCopyish & SubProto#>>}}
_ = ProtosBound2() // expected-error {{generic parameter 'Foo' could not be inferred}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{19-19=<<#Foo: NSCopyish & SubProto#>>}}
_ = ProtosBound3() // expected-error {{generic parameter 'Foo' could not be inferred}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{19-19=<<#Foo: NSCopyish & SubProto#>>}}
_ = AnyClassAndProtoBound() // expected-error {{generic parameter 'Foo' could not be inferred}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{28-28=<<#Foo: SubProto & AnyObject#>>}}
_ = AnyClassAndProtoBound2() // expected-error {{generic parameter 'Foo' could not be inferred}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{29-29=<<#Foo: SubProto & AnyObject#>>}}
_ = ClassAndProtoBound() // expected-error {{generic struct 'ClassAndProtoBound' requires that 'X' conform to 'SubProto'}}
_ = ClassAndProtosBound()
// expected-error@-1 {{generic struct 'ClassAndProtosBound' requires that 'X' conform to 'SubProto'}}
// expected-error@-2 {{generic struct 'ClassAndProtosBound' requires that 'X' conform to 'NSCopyish'}}
_ = ClassAndProtosBound2()
// expected-error@-1 {{generic struct 'ClassAndProtosBound2' requires that 'X' conform to 'SubProto'}}
// expected-error@-2 {{generic struct 'ClassAndProtosBound2' requires that 'X' conform to 'NSCopyish'}}
_ = Pair()
// expected-error@-1 {{generic parameter 'T' could not be inferred}}
// expected-error@-2 {{generic parameter 'U' could not be inferred}}
// expected-note@-3 {{explicitly specify the generic arguments to fix this issue}} {{11-11=<Any, Any>}}
_ = Pair(first: S()) // expected-error {{generic parameter 'U' could not be inferred}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{11-11=<S, Any>}}
_ = Pair(second: S()) // expected-error {{generic parameter 'T' could not be inferred}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{11-11=<Any, S>}}
}
func testFixItClassBound() {
// We infer a single class bound for simple cases in expressions...
let x = ClassBound()
let x1: String = x // expected-error {{cannot convert value of type 'ClassBound<X>' to specified type 'String'}}
let y = ClassBound2()
let y1: String = y // expected-error {{cannot convert value of type 'ClassBound2<X>' to specified type 'String'}}
// ...but not in types.
let z1: ClassBound // expected-error {{reference to generic type 'ClassBound' requires arguments in <...>}} {{21-21=<<#Foo: X#>>}}
let z2: ClassBound2 // expected-error {{reference to generic type 'ClassBound2' requires arguments in <...>}} {{22-22=<<#Foo: X#>>}}
}
func testFixItCasting(x: Any) {
_ = x as! FullyGeneric // expected-error {{generic parameter 'Foo' could not be inferred}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{25-25=<Any>}}
}
func testFixItContextualKnowledge() {
// FIXME: These could propagate backwards.
let _: Int = Pair().first // expected-error {{generic parameter 'U' could not be inferred}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{20-20=<Int, Any>}}
let _: Int = Pair().second // expected-error {{generic parameter 'T' could not be inferred}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{20-20=<Any, Int>}}
}
func testFixItTypePosition() {
let _: FullyGeneric // expected-error {{reference to generic type 'FullyGeneric' requires arguments in <...>}} {{22-22=<Any>}}
let _: ProtoBound // expected-error {{reference to generic type 'ProtoBound' requires arguments in <...>}} {{20-20=<<#Foo: SubProto#>>}}
let _: ObjCProtoBound // expected-error {{reference to generic type 'ObjCProtoBound' requires arguments in <...>}} {{24-24=<NSCopyish>}}
let _: AnyClassBound // expected-error {{reference to generic type 'AnyClassBound' requires arguments in <...>}} {{23-23=<AnyObject>}}
let _: ProtosBound // expected-error {{reference to generic type 'ProtosBound' requires arguments in <...>}} {{21-21=<<#Foo: NSCopyish & SubProto#>>}}
}
func testFixItNested() {
_ = Array<FullyGeneric>() // expected-error {{generic parameter 'Foo' could not be inferred}}
// expected-note@-1 {{explicitly specify the generic arguments to fix this issue}} {{25-25=<Any>}}
_ = [FullyGeneric]() // expected-error {{generic parameter 'Foo' could not be inferred}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{20-20=<Any>}}
_ = FullyGeneric<FullyGeneric>() // expected-error {{generic parameter 'Foo' could not be inferred}}
// expected-note@-1 {{explicitly specify the generic arguments to fix this issue}} {{32-32=<Any>}}
_ = Pair<
FullyGeneric,
// expected-error@-1 {{generic parameter 'Foo' could not be inferred}}
// expected-note@-2 {{explicitly specify the generic arguments to fix this issue}} {{17-17=<Any>}}
FullyGeneric
// expected-error@-1 {{generic parameter 'Foo' could not be inferred}}
// expected-note@-2 {{explicitly specify the generic arguments to fix this issue}} {{17-17=<Any>}}
>()
_ = Pair<
FullyGeneric<Any>,
FullyGeneric
// expected-error@-1 {{generic parameter 'Foo' could not be inferred}}
// expected-note@-2 {{explicitly specify the generic arguments to fix this issue}} {{17-17=<Any>}}
>()
_ = Pair<
FullyGeneric,
// expected-error@-1 {{generic parameter 'Foo' could not be inferred}}
// expected-note@-2 {{explicitly specify the generic arguments to fix this issue}} {{17-17=<Any>}}
FullyGeneric<Any>
>()
_ = pair(
FullyGeneric(),
// expected-error@-1 {{generic parameter 'Foo' could not be inferred}}
// expected-note@-2 {{explicitly specify the generic arguments to fix this issue}} {{17-17=<Any>}}
FullyGeneric()
// expected-error@-1 {{generic parameter 'Foo' could not be inferred}}
// expected-note@-2 {{explicitly specify the generic arguments to fix this issue}} {{17-17=<Any>}}
)
_ = pair(
FullyGeneric<Any>(),
FullyGeneric()
// expected-error@-1 {{generic parameter 'Foo' could not be inferred}}
// expected-note@-2 {{explicitly specify the generic arguments to fix this issue}} {{17-17=<Any>}}
)
_ = pair(
FullyGeneric(),
// expected-error@-1 {{generic parameter 'Foo' could not be inferred}}
// expected-note@-2 {{explicitly specify the generic arguments to fix this issue}} {{17-17=<Any>}}
FullyGeneric<Any>()
)
}
// rdar://problem/26845038
func occursCheck26845038(a: [Int]) {
_ = Array(a)[0]
}
// rdar://problem/29633747
extension Array where Element: Hashable {
public func trimmed(_ elements: [Element]) -> SubSequence {
return []
}
}
func rdar29633747(characters: String) {
let _ = Array(characters).trimmed(["("])
}
// Null pointer dereference in noteArchetypeSource()
class GenericClass<A> {}
// expected-note@-1 {{'A' declared as parameter to type 'GenericClass'}}
func genericFunc<T>(t: T) {
_ = [T: GenericClass] // expected-error {{generic parameter 'A' could not be inferred}}
// expected-note@-1 {{explicitly specify the generic arguments to fix this issue}}
// expected-error@-2 {{generic struct 'Dictionary' requires that 'T' conform to 'Hashable'}}
}
// https://github.com/apple/swift/issues/46113
do {
struct S<T> {}
func arg_int(_: inout S<Int>) {}
func arg_gen<T>(_: inout S<T>) {}
func f1(t: S<Int>) {
let _ = arg_int(&t) // expected-error {{cannot pass immutable value as inout argument: 't' is a 'let' constant}}
let _ = arg_gen(&t) // expected-error {{cannot pass immutable value as inout argument: 't' is a 'let' constant}}
}
func f2<T>(t: S<T>) {
let _ = arg_gen(&t) // expected-error {{cannot pass immutable value as inout argument: 't' is a 'let' constant}}
}
}
class testStdlibType {
let _: Array
// expected-error@-1 {{reference to generic type 'Array' requires arguments in <...>}} {{15-15=<Any>}}
// expected-error@-2 {{property declaration does not bind any variables}}
}
// rdar://problem/32697033
protocol P3 {
associatedtype InnerAssoc
}
protocol P4 {
associatedtype OuterAssoc: P3
}
struct S3 : P3 {
typealias InnerAssoc = S4
}
struct S4: P4 {
typealias OuterAssoc = S3
}
public struct S5 {
func f<Model: P4, MO> (models: [Model])
where Model.OuterAssoc == MO, MO.InnerAssoc == Model {
}
func g<MO, Model: P4> (models: [Model])
where Model.OuterAssoc == MO, MO.InnerAssoc == Model {
}
func f(arr: [S4]) {
f(models: arr)
g(models: arr)
}
}
// rdar://problem/24329052 - QoI: call argument archetypes not lining up leads to ambiguity errors
struct S_24329052<T> { // expected-note {{generic parameter 'T' of generic struct 'S_24329052' declared here}} expected-note {{'T' previously declared here}}
var foo: (T) -> Void
// expected-note@+1 {{generic parameter 'T' of instance method 'bar(_:)' declared here}}
func bar<T>(_ v: T) { foo(v) }
// expected-error@-1 {{cannot convert value of type 'T' (generic parameter of instance method 'bar(_:)') to expected argument type 'T' (generic parameter of generic struct 'S_24329052')}}
// expected-warning@-2 {{generic parameter 'T' shadows generic parameter from outer scope with the same name; this is an error in the Swift 6 language mode}}
}
extension Sequence {
var rdar24329052: (Element) -> Void { fatalError() }
// expected-note@+1 {{generic parameter 'Element' of instance method 'foo24329052(_:)' declared here}}
func foo24329052<Element>(_ v: Element) { rdar24329052(v) }
// expected-error@-1 {{cannot convert value of type 'Element' (generic parameter of instance method 'foo24329052(_:)') to expected argument type 'Self.Element' (associated type of protocol 'Sequence')}}
}
func rdar27700622<E: Comparable>(_ input: [E]) -> [E] {
let pivot = input.first!
let lhs = input.dropFirst().filter { $0 <= pivot }
let rhs = input.dropFirst().filter { $0 > pivot }
return rdar27700622(lhs) + [pivot] + rdar27700622(rhs) // Ok
}
// rdar://problem/22898292 - Type inference failure with constrained subclass
protocol P_22898292 {}
do {
func construct_generic<T: P_22898292>(_ construct: () -> T) -> T { return construct() }
class A {}
class B : A, P_22898292 {}
func foo() -> B { return B() }
func bar(_ value: A) {}
func baz<T: A>(_ value: T) {}
func rdar_22898292_1() {
let x = construct_generic { foo() } // returns A
bar(x) // Ok
bar(construct_generic { foo() }) // Ok
}
func rdar22898292_2<T: B>(_ d: T) {
_ = { baz($0) }(construct_generic { d }) // Ok
}
}
// rdar://problem/35541153 - Generic parameter inference bug
func rdar35541153() {
func foo<U: Equatable, V: Equatable, C: Collection>(_ c: C) where C.Element == (U, V) {}
func bar<K: Equatable, V, C: Collection>(_ c: C, _ k: K, _ v: V) where C.Element == (K, V) {}
let x: [(a: Int, b: Int)] = []
let y: [(k: String, v: Int)] = []
foo(x) // Ok
bar(y, "ultimate question", 42) // Ok
}
// rdar://problem/38159133
// https://github.com/apple/swift/issues/49673
// Swift 4.1 Xcode 9.3b4 regression
protocol P_38159133 {}
do {
class Super {}
class A: Super, P_38159133 {}
class B: Super, P_38159133 {}
func rdar38159133(_ a: A?, _ b: B?) {
let _: [P_38159133] = [a, b].compactMap { $0 } // Ok
}
}
func rdar35890334(_ arr: inout [Int]) {
_ = arr.popFirst() // expected-error {{referencing instance method 'popFirst()' on 'Collection' requires the types '[Int]' and 'ArraySlice<Int>' be equivalent}}
}
// rdar://problem/39616039
func rdar39616039() {
func foo<V>(default: V, _ values: [String: V]) -> V {
return values["foo"] ?? `default`
}
var a = foo(default: 42, ["foo": 0])
a += 1 // ok
var b = foo(default: 42.0, ["foo": 0])
b += 1 // ok
var c = foo(default: 42.0, ["foo": Float(0)])
c += 1 // ok
}
// https://github.com/apple/swift/issues/50608
do {
struct UIFont {
init(ofSize: Float) {}
}
func switchOnCategory<T>(_ categoryToValue: [Int: T]) -> T {
fatalError()
}
let _: UIFont = .init(ofSize: switchOnCategory([0: 15.5, 1: 20.5]))
}
// rdar://problem/40537858 - Ambiguous diagnostic when type is missing conformance
func rdar40537858() {
struct S {
struct Id {}
var id: Id
}
struct List<T: Collection, E: Hashable> { // expected-note {{where 'E' = 'S.Id'}}
typealias Data = T.Element
init(_: T, id: KeyPath<Data, E>) {}
}
var arr: [S] = []
_ = List(arr, id: \.id) // expected-error {{generic struct 'List' requires that 'S.Id' conform to 'Hashable'}}
enum E<T: P> { // expected-note 2 {{where 'T' = 'S'}}
case foo(T)
case bar([T])
}
var s = S(id: S.Id())
let _: E = .foo(s) // expected-error {{generic enum 'E' requires that 'S' conform to 'P'}}
let _: E = .bar([s]) // expected-error {{generic enum 'E' requires that 'S' conform to 'P'}}
}
// https://github.com/apple/swift/issues/51439
struct BottleLayout {
let count : Int
}
let arr = [BottleLayout]()
let layout = BottleLayout(count:1)
let ix = arr.firstIndex(of:layout) // expected-error {{referencing instance method 'firstIndex(of:)' on 'Collection' requires that 'BottleLayout' conform to 'Equatable'}}
let _: () -> UInt8 = { .init("a" as Unicode.Scalar) } // expected-error {{missing argument label 'ascii:' in call}}
// https://github.com/apple/swift/issues/51569
func compare<C: Collection, Key: Hashable, Value: Equatable>(c: C)
-> Bool where C.Element == (key: Key, value: Value)
{
_ = Dictionary(uniqueKeysWithValues: Array(c))
}
// https://github.com/apple/swift/issues/50517
struct S1_50517<Bar> {
func doSomething() {}
}
extension S1_50517 where Bar: String {} // expected-error {{type 'Bar' constrained to non-protocol, non-class type 'String'}} expected-note {{use 'Bar == String' to require 'Bar' to be 'String'}} {{29-30= ==}}
protocol P1_50517 {
associatedtype Bar
}
extension P1_50517 where Bar: String {} // expected-error {{type 'Self.Bar' constrained to non-protocol, non-class type 'String'}} expected-note {{use 'Bar == String' to require 'Bar' to be 'String'}} {{29-30= ==}}
protocol P2_50517 {
associatedtype Foo
}
protocol P3_50517 {
associatedtype Assoc: P2_50517
}
struct S2_50517<T: P3_50517> {}
extension S2_50517 where T.Assoc.Foo: String {} // expected-error {{type 'T.Assoc.Foo' constrained to non-protocol, non-class type 'String'}} expected-note {{use 'T.Assoc.Foo == String' to require 'T.Assoc.Foo' to be 'String'}} {{37-38= ==}}
struct S3_50517<T: Sequence> where T.Element: String {} // expected-error {{type 'T.Element' constrained to non-protocol, non-class type 'String'}} expected-note {{use 'T.Element == String' to require 'T.Element' to be 'String'}} {{45-46= ==}}
func f_50517<T: Sequence>(foo: T) where T.Element: String {} // expected-error {{type 'T.Element' constrained to non-protocol, non-class type 'String'}} expected-note {{use 'T.Element == String' to require 'T.Element' to be 'String'}} {{50-51= ==}}
protocol P4_50517 {
func S<T : Sequence>(bar: T) where T.Element: String // expected-error {{type 'T.Element' constrained to non-protocol, non-class type 'String'}} expected-note {{use 'T.Element == String' to require 'T.Element' to be 'String'}} {{47-48= ==}}
}
struct A<T: String> {} // expected-error {{type 'T' constrained to non-protocol, non-class type 'String'}}
struct B<T> where T: String {} // expected-error {{type 'T' constrained to non-protocol, non-class type 'String'}}
protocol C {
associatedtype Foo: String // expected-error {{type 'Self.Foo' constrained to non-protocol, non-class type 'String'}}
}
protocol D {
associatedtype Foo where Foo: String // expected-error {{type 'Self.Foo' constrained to non-protocol, non-class type 'String'}}
}
func member_ref_with_explicit_init() {
struct S<T: P> { // expected-note {{where 'T' = 'Int'}}
init(_: T) {}
init(_: T, _ other: Int = 42) {}
}
_ = S.init(42)
// expected-error@-1 {{generic struct 'S' requires that 'Int' conform to 'P'}}
}
protocol Q {
init<T : P>(_ x: T) // expected-note 2{{where 'T' = 'T'}}
}
// https://github.com/apple/swift/issues/53091
struct S_53091 {
init<T : P>(_ x: T) {} // expected-note 3{{where 'T' = 'T'}}
func bar<T>(_ x: T, _ s: S_53091, _ q: Q) {
S_53091.self(x) // expected-error {{initializer 'init(_:)' requires that 'T' conform to 'P'}}
type(of: s)(x) // expected-error {{initializer 'init(_:)' requires that 'T' conform to 'P'}}
// expected-error@-1 {{initializing from a metatype value must reference 'init' explicitly}}
Q.self(x) // expected-error {{initializer 'init(_:)' requires that 'T' conform to 'P'}}
// expected-error@-1 {{type 'any Q' cannot be instantiated}}
type(of: q)(x) // expected-error {{initializer 'init(_:)' requires that 'T' conform to 'P'}}
// expected-error@-1 {{initializing from a metatype value must reference 'init' explicitly}}
var ty = S_53091.self
ty(x) // expected-error {{initializer 'init(_:)' requires that 'T' conform to 'P'}}
// expected-error@-1 {{initializing from a metatype value must reference 'init' explicitly}}
}
}
// rdar://problem/51203824
// https://github.com/apple/swift/issues/49551
// Poor diagnostics when attempting to access members on unfulfilled
// generic type
func f_49551() {
struct E<T> { // expected-note 4 {{'T' declared as parameter to type 'E'}}
static var foo: String { return "" }
var bar: String { return "" }
static func baz() -> String { return "" }
func qux() -> String { return "" }
}
let _: Any = E.foo
// expected-error@-1 {{generic parameter 'T' could not be inferred}}
// expected-note@-2 {{explicitly specify the generic arguments to fix this issue}} {{17-17=<Any>}}
let _: Any = E().bar
// expected-error@-1 {{generic parameter 'T' could not be inferred}}
// expected-note@-2 {{explicitly specify the generic arguments to fix this issue}} {{17-17=<Any>}}
let _: Any = E.baz()
// expected-error@-1 {{generic parameter 'T' could not be inferred}}
// expected-note@-2 {{explicitly specify the generic arguments to fix this issue}} {{17-17=<Any>}}
let _: Any = E().qux()
// expected-error@-1 {{generic parameter 'T' could not be inferred}}
// expected-note@-2 {{explicitly specify the generic arguments to fix this issue}} {{17-17=<Any>}}
}
func test_generic_subscript_with_missing_arg() {
struct S<T> {
subscript<U>(_: T) -> S<U> { fatalError() }
// expected-note@-1 {{in call to 'subscript(_:)'}}
}
func test(_ s: S<Int>) {
_ = s[0] // expected-error {{generic parameter 'U' could not be inferred}}
}
}
func rdar_50007727() {
struct A<T> { // expected-note {{'T' declared as parameter to type 'A'}}
struct B<U> : ExpressibleByStringLiteral {
init(stringLiteral value: String) {}
}
}
struct S {}
let _ = A.B<S>("hello")
// expected-error@-1 {{generic parameter 'T' could not be inferred in cast to 'A.B'}}
// expected-note@-2 {{explicitly specify the generic arguments to fix this issue}} {{12-12=<Any>}}
}
// rdar://problem/51413254
infix operator ==>
struct Key {
init(_ key: String) {}
}
func ==> (lhs: Any, rhs: Key) throws -> Any {
return 0
}
func ==> <A>(lhs: Any, rhs: Key) throws -> A {
fatalError()
}
struct R_51413254 {
var str: String = ""
mutating func test(_ anyDict: Any) throws {
self.str = try anyDict ==> Key("a") // Ok
}
}
func test_correct_identification_of_requirement_source() {
struct X<T: P> { // expected-note {{where 'T' = 'Int'}}
init<U: P>(_: T, _: U) {} // expected-note {{where 'U' = 'Int'}}
}
struct A : P {
static func foo(_ arg: A) -> A {
return A()
}
}
_ = X(17, A())
// expected-error@-1 {{generic struct 'X' requires that 'Int' conform to 'P'}}
_ = X(A(), 17)
// expected-error@-1 {{initializer 'init(_:_:)' requires that 'Int' conform to 'P'}}
}
// https://github.com/apple/swift/issues/53836
struct S_53836<T> {
subscript<U : P & Hashable>(x x: U) -> U { x } // expected-note {{where 'U' = 'Int'}}
}
extension S_53836 where T : P { // expected-note {{where 'T' = 'Int'}}
var foo: Int { 0 }
}
func test_identification_of_key_path_component_callees() {
_ = \S_53836<Int>.foo // expected-error {{property 'foo' requires that 'Int' conform to 'P'}}
_ = \S_53836<Int>.[x: 5] // expected-error {{subscript 'subscript(x:)' requires that 'Int' conform to 'P'}}
}
// https://github.com/apple/swift/issues/53891
func f_53891(_ value: [String]) {
var arr: Set<String> = []
arr.insert(value)
// expected-error@-1 {{cannot convert value of type '[String]' to expected argument type 'String'}}
}
func test_dictionary_with_generic_mismatch_in_key_or_value() {
struct S<T> : Hashable {}
// expected-note@-1 2 {{arguments to generic parameter 'T' ('Int' and 'Bool') are expected to be equal}}
let _: [Int: S<Bool>] = [0: S<Bool>(), 1: S<Int>()]
// expected-error@-1 {{cannot convert value of type 'S<Int>' to expected dictionary value type 'S<Bool>'}}
let _: [S<Bool>: Int] = [S<Int>(): 42]
// expected-error@-1 {{cannot convert value of type 'S<Int>' to expected dictionary key type 'S<Bool>'}}
}
// rdar://problem/56212087 - unable to infer type for generic parameter `T`
func rdar56212087() {
func setValue(_: Any?, forKey: String) {}
func foo<T: ExpressibleByStringLiteral>(_: String, _: T) -> T {
fatalError()
}
setValue(foo("", ""), forKey: "") // Ok (T is inferred as a `String` instead of `Any?`)
}
// rdar://77233864 - Ternary operator fails to deduce non-default literal type in SwiftUI preview
func test_ternary_operator_with_regular_conformance_to_literal_protocol() {
// Note that in this case `ExpressibleByIntegerLiteral` is a non-literal requirement
func test<T: ExpressibleByIntegerLiteral>(_: T) -> T {
fatalError()
}
func bug(_: Float?) {}
bug(true ? test(0) : test(42)) // Ok - type is `CGFloat` for 0 and 42
}
// rdar://78623338 - crash due to leftover inactive constraints
func rdar78623338() {
func any<T : Sequence>(_ sequence: T) -> AnySequence<T.Element> {
// expected-note@-1 {{required by local function 'any' where 'T' = '() -> ReversedCollection<ClosedRange<Int>>'}}
AnySequence(sequence.makeIterator)
}
let _ = [
any(0...3),
// TODO: It should be possible to suggest making a call to `reserved` here but we don't have machinery to do so
// at the moment because there is no way to go from a requirement to the underlying argument/parameter location.
any((1...3).reversed) // expected-error {{type '() -> ReversedCollection<ClosedRange<Int>>' cannot conform to 'Sequence'}}
// expected-note@-1 {{only concrete types such as structs, enums and classes can conform to protocols}}
]
}
// rdar://78781552 - crash in `getFunctionArgApplyInfo`
func rdar78781552() {
struct Test<Data, Content> where Data : RandomAccessCollection {
// expected-note@-1 {{where 'Data' = '(((Int) throws -> Bool) throws -> [Int])?'}}
// expected-note@-2 {{'init(data:filter:)' declared here}}
// expected-note@-3 {{'Content' declared as parameter to type 'Test'}}
var data: [Data]
var filter: (Data.Element) -> Content
}
func test(data: [Int]?) {
Test(data?.filter)
// expected-error@-1 {{generic struct 'Test' requires that '(((Int) throws -> Bool) throws -> [Int])?' conform to 'RandomAccessCollection'}}
// expected-error@-2 {{generic parameter 'Content' could not be inferred}} expected-note@-2 {{explicitly specify the generic arguments to fix this issue}}
// expected-error@-3 {{cannot convert value of type '(((Int) throws -> Bool) throws -> [Int])?' to expected argument type '[(((Int) throws -> Bool) throws -> [Int])?]'}}
// expected-error@-4 {{missing argument label 'data:' in call}}
// expected-error@-5 {{missing argument for parameter 'filter' in call}}
}
}
// rdar://79757320 - failed to produce a diagnostic when unresolved dependent member is used in function result position
protocol R_79757320 {
associatedtype In
associatedtype Out
}
func rdar79757320() {
struct Value<W> {
init(_: W) {}
func formatted() -> String { "" }
func formatted<T : R_79757320>(_: T) -> T.Out where T.In == Value<W> { fatalError() }
}
struct Container {
var value: String
}
// FIXME: There has to be a way to propagate holes that makes it easy to suppress failures caused by missing members.
_ = Container(value: Value(42).formatted(.S(a: .a, b: .b(0)))) // expected-error {{type 'R_79757320' has no member 'S'}}
// expected-error@-1 {{cannot infer contextual base in reference to member 'a'}}
// expected-error@-2 {{cannot infer contextual base in reference to member 'b'}}
}
protocol P_eaf0300ff7a {}
do {
struct Outer<T: P_eaf0300ff7a> {
struct Inner<U> {}
func container<V>() -> Inner<V> {
return Inner()
}
}
}
// https://github.com/apple/swift/issues/43527
do {
struct Box<Contents, U> {}
class Sweets {}
class Chocolate {}
struct Gift<Contents> {
// expected-note@-1 2 {{arguments to generic parameter 'Contents' ('Chocolate' and 'Sweets') are expected to be equal}}
init(_: Box<[Contents], Never>) {}
}
let box = Box<[Chocolate], Never>()
var g1: Gift<Sweets>
g1 = Gift<Chocolate>(box)
// expected-error@-1 {{cannot assign value of type 'Gift<Chocolate>' to type 'Gift<Sweets>'}}
let g2: Gift<Sweets> = Gift<Chocolate>(box)
// expected-error@-1 {{cannot assign value of type 'Gift<Chocolate>' to type 'Gift<Sweets>'}}
}
func testOverloadGenericVarFn() {
struct S<T> {
var foo: T
func foo(_ y: Int) {}
init() { fatalError() }
}
// Make sure we can pick the variable overload over the function.
S<(String) -> Void>().foo("")
S<((String) -> Void)?>().foo?("")
S<((String) -> Void)?>().foo!("")
}
do {
func foo<T, U>(_: T, _: U) where T: Sequence, U: Sequence, T.Element == U.Element {}
// expected-note@-1 {{required by local function 'foo' where 'T' = 'Set<Int>.Type'}}
// expected-note@-2 {{required by local function 'foo' where 'U' = 'Array<String>.Type'}}
// expected-note@-3 {{where 'T.Element' = 'Set<Int>.Type.Element', 'U.Element' = 'Array<String>.Type.Element'}}
foo(Set<Int>, Array<String>)
// expected-error@-1 {{type 'Set<Int>.Type' cannot conform to 'Sequence'}}
// expected-error@-2 {{type 'Array<String>.Type' cannot conform to 'Sequence'}}
// expected-error@-3 {{local function 'foo' requires the types 'Set<Int>.Type.Element' and 'Array<String>.Type.Element' be equivalent}}
// expected-note@-4 2 {{only concrete types such as structs, enums and classes can conform to protocols}}
}
// https://github.com/apple/swift/issues/56173
protocol P_56173 {
associatedtype Element
}
protocol Q_56173 {
associatedtype Element
}
func test_requirement_failures_in_ambiguous_context() {
struct A : P_56173 {
typealias Element = String
}
struct B : Q_56173 {
typealias Element = Int
}
func f1<T: Equatable>(_: T, _: T) {} // expected-note {{where 'T' = 'A'}}
f1(A(), B()) // expected-error {{local function 'f1' requires that 'A' conform to 'Equatable'}}
// expected-error@-1 {{cannot convert value of type 'B' to expected argument type 'A'}}
func f2<T: P_56173, U: P_56173>(_: T, _: U) {}
// expected-note@-1 {{candidate requires that 'B' conform to 'P_56173' (requirement specified as 'U' : 'P_56173')}}
func f2<T: Q_56173, U: Q_56173>(_: T, _: U) {}
// expected-note@-1 {{candidate requires that 'A' conform to 'Q_56173' (requirement specified as 'T' : 'Q_56173')}}
f2(A(), B()) // expected-error {{no exact matches in call to local function 'f2'}}
func f3<T: P_56173>(_: T) where T.Element == Int {}
// expected-note@-1 {{candidate requires that the types 'A.Element' (aka 'String') and 'Int' be equivalent (requirement specified as 'T.Element' == 'Int')}}
func f3<U: Q_56173>(_: U) where U.Element == String {}
// expected-note@-1 {{candidate requires that 'A' conform to 'Q_56173' (requirement specified as 'U' : 'Q_56173')}}
f3(A()) // expected-error {{no exact matches in call to local function 'f3'}}
}
// rdar://106054263 - failed to produce a diagnostic upon generic argument mismatch
func test_mismatches_with_dependent_member_generic_arguments() {
struct Binding<T, U> {}
// expected-note@-1 {{arguments to generic parameter 'T' ('Double?' and 'Data.SomeAssociated' (aka 'String')) are expected to be equal}}
// expected-note@-2 {{arguments to generic parameter 'U' ('Int' and 'Data.SomeAssociated' (aka 'String')) are expected to be equal}}
struct Data : SomeProtocol {
typealias SomeAssociated = String
}
func test1<T: SomeProtocol>(_: Binding<T.SomeAssociated, T.SomeAssociated>, _: T) where T.SomeAssociated == String {
}
func test2<T: SomeProtocol>(_: Optional<T.SomeAssociated>, _: T) where T.SomeAssociated == String {
}
test1(Binding<Double?, Int>(), Data())
// expected-error@-1 {{cannot convert value of type 'Binding<Double?, Int>' to expected argument type 'Binding<Data.SomeAssociated, Data.SomeAssociated>'}}
test2(Optional<Int>(nil), Data())
// expected-error@-1 {{cannot convert value of type 'Optional<Int>' to expected argument type 'Optional<Data.SomeAssociated>'}}
// expected-note@-2 {{arguments to generic parameter 'Wrapped' ('Int' and 'Data.SomeAssociated' (aka 'String')) are expected to be equal}}
}
extension Dictionary where Value == Any { // expected-note {{where 'Value' = 'any P'}}
func compute() {}
}
do {
struct S {
var test: [String: any P] = [:]
}
func test_existential_mismatch(s: S) {
s.test.compute()
// expected-error@-1 {{referencing instance method 'compute()' on 'Dictionary' requires the types 'any P' and 'Any' be equivalent}}
}
}
// https://github.com/swiftlang/swift/issues/77003
do {
func f<T, U>(_: T.Type, _ fn: (T) -> U?, _: (U) -> ()) {}
struct Task<E> {
init(_: () -> ()) where E == Never {}
init(_: () throws -> ()) where E == Error {}
}
func test(x: Int?.Type) {
// Note that it's important that Task stays unused, using `_ = ` changes constraint generation behavior.
f(x, { $0 }, { _ in Task {} }) // expected-warning {{result of 'Task<E>' initializer is unused}}
}
}
func testHolePropagation() {
struct S<T: P> {}
struct R {}
// The hole from the contextual type should propagate such that we don't
// complain about not being able to infer 'T'.
_ = { () -> S<R> in S() } // expected-error {{type 'R' does not conform to protocol 'P'}}
_ = { () -> S<R> in return S() } // expected-error {{type 'R' does not conform to protocol 'P'}}
_ = { () -> S<R> in (); return S() } // expected-error {{type 'R' does not conform to protocol 'P'}}
let _: () -> S<R> = { S() } // expected-error {{type 'R' does not conform to protocol 'P'}}
let _: () -> S<R> = { return S() } // expected-error {{type 'R' does not conform to protocol 'P'}}
let _: () -> S<R> = { (); return S() } // expected-error {{type 'R' does not conform to protocol 'P'}}
_ = { S() }() as S<R> // expected-error {{type 'R' does not conform to protocol 'P'}}
_ = { return S() }() as S<R> // expected-error {{type 'R' does not conform to protocol 'P'}}
_ = { (); return S() } as () -> S<R> // expected-error {{type 'R' does not conform to protocol 'P'}}
func makeT<T>() -> T {}
_ = { () -> (S<R>, Int) in (makeT(), 0) } // expected-error {{type 'R' does not conform to protocol 'P'}}
_ = { () -> (S<R>, Int) in return (makeT(), 0) } // expected-error {{type 'R' does not conform to protocol 'P'}}
_ = { () -> (S<R>, Int) in (); return (makeT(), 0) } // expected-error {{type 'R' does not conform to protocol 'P'}}
}
@freestanding(expression) macro overloadedMacro<T>() -> String = #file
@freestanding(expression) macro overloadedMacro<T>(_ x: T = 0) -> String = #file
do {
func foo(_ fn: () -> Int) {}
func foo(_ fn: () -> String) {}
// Make sure we only emit a single note here.
foo {
#overloadedMacro < Undefined >
// expected-error@-1 {{cannot find type 'Undefined' in scope}}
// expected-note@-2 {{while parsing this '<' as a type parameter bracket}}
}
}