Add executable test for named opaque result types

test/Interpreter/named_opaque_result_types.swift

@@ -0,0 +1,76 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift -swift-version 5 -Xfrontend -enable-experimental-named-opaque-types %s -o %t/a.out
+// RUN: %target-run %t/a.out | %FileCheck %s
+
+// REQUIRES: executable_test
+
+@available(iOS 13, macOS 10.15, tvOS 13, watchOS 6, *)
+dynamic func lazyMapCollection<C: Collection, T>(_ collection: C, body: @escaping (C.Element) -> T)
+    -> <R: Collection where R.Element == T> R {
+  return collection.lazy.map { body($0) }
+}
+
+@available(iOS 13, macOS 10.15, tvOS 13, watchOS 6, *)
+dynamic func lazyMapCollection2<C: Collection, T>(_ collection: C, body: @escaping (C.Element) -> T)
+    -> <R: Collection where R.Element == T> R {
+  collection.lazy.map { body($0) }
+}
+
+@available(iOS 13, macOS 10.15, tvOS 13, watchOS 6, *)
+dynamic func unzipCollection<C: Collection, T, U: Hashable>(_ collection: C)
+-> <R1: Collection, R2: Collection where R1.Element == T, R2.Element == U> (R1, R2) where C.Element == (T, U) {
+  return (Array(collection.map { $0.0 }), Set(collection.map { $0.1 }))
+}
+
+protocol P {
+  associatedtype A
+  func f() -> A
+}
+
+@available(iOS 13, macOS 10.15, tvOS 13, watchOS 6, *)
+struct X<T, U: Hashable>: P {
+  var data: [(T, U)]
+
+  func f() -> <
+      R1: Collection, R2: Collection where R1.Element == T, R2.Element == U
+  > (R1, R2) {
+    // FIXME: Use unzipCollection here
+    return (Array(data.map { $0.0 }), Set(data.map { $0.1 }))
+  }
+}
+
+func getP_A<T: P>(_: T.Type) -> Any.Type {
+  return T.A.self
+}
+
+if #available(iOS 13, macOS 10.15, tvOS 13, watchOS 6, *) {
+  // CHECK: {{[1.0, 2.0, 3.0]|too old}}
+  let array = [1, 2, 3]
+  let x = lazyMapCollection(array) { Double($0) }
+  print(x)
+
+  // CHECK: {{[0.5, 1.0, 1.5]|too old}}
+  let x2 = lazyMapCollection2(array) { Double($0) / 2.0 }
+  print(x2)
+
+  let array2 = [(1, "Hello"), (2, "World"), (3, "!")]
+  let x3 = unzipCollection(array2)
+
+  // CHECK: {{[1, 2, 3]|too old}}
+  print(x3.0)
+
+  // CHECK: {{["Hello", "World", "!"]|too old}}
+  print(x3.1)
+
+  // CHECK: {{(Array<Int>, Set<String>)|too old}}
+  let paType = getP_A(X<Int, String>.self)
+  print(paType)
+  typealias ExpectedPAType = ([Int], Set<String>)
+  assert(paType == ExpectedPAType.self)
+} else {
+  print("too old")
+  print("too old")
+  print("too old")
+  print("too old")
+  print("too old")
+}