Test: Add executable tests for references to @objc optional methods

Author: AnthonyLatsis

test/Interpreter/objc_protocols.swift

@@ -23,4 +23,85 @@ ObjCProtocolsTest.test("InitRequirement") {
   _ = t.init()
 }
 
+@objc protocol OptionalRequirements {
+  @objc optional func returnNumber(n: Int) -> Int
+  @objc optional static func returnNumberStatic(n: Int) -> Int
+
+  @objc optional func returnSelf() -> Self
+}
+
+ObjCProtocolsTest.test("OptionalMethodReferenceTypes") {
+  class Base {}
+  class Derived: Base, OptionalRequirements {}
+
+  let exist: OptionalRequirements = Derived()
+  let existComposition: Base & OptionalRequirements = Derived()
+  let existMeta: OptionalRequirements.Type = Derived.self
+
+  expectEqual(type(of: exist.returnNumber),
+              ((Int) -> Int)?.self)
+  expectEqual(type(of: existMeta.returnNumberStatic),
+              ((Int) -> Int)?.self)
+  expectEqual(type(of: OptionalRequirements.returnNumber),
+              ((OptionalRequirements) -> ((Int) -> Int)?).self)
+  expectEqual(type(of: (Base & OptionalRequirements).returnNumber),
+              ((Base & OptionalRequirements) -> ((Int) -> Int)?).self)
+
+  expectEqual(type(of: exist.returnSelf),
+              (() -> OptionalRequirements)?.self)
+  expectEqual(type(of: existComposition.returnSelf),
+              (() -> Base & OptionalRequirements)?.self)
+  expectEqual(type(of: OptionalRequirements.returnSelf),
+              ((OptionalRequirements) -> (() -> OptionalRequirements)?).self)
+  expectEqual(type(of: (Base & OptionalRequirements).returnSelf),
+              ((Base & OptionalRequirements) -> (() -> Base & OptionalRequirements)?).self)
+
+}
+
+ObjCProtocolsTest.test("OptionalMethodReferencesNoImplementation") {
+  class Class: OptionalRequirements {}
+
+  let exist: OptionalRequirements = Class()
+  let existMeta: OptionalRequirements.Type = Class.self
+
+  expectNil(exist.returnNumber)
+  expectNil(existMeta.returnNumberStatic)
+  expectNil(OptionalRequirements.returnNumber(exist))
+
+  expectNil(exist.returnSelf)
+  expectNil(OptionalRequirements.returnSelf(exist))
+}
+
+ObjCProtocolsTest.test("OptionalMethodReferencesWithImplementation") {
+  class Class: OptionalRequirements {
+    func returnSelf() -> Self {
+      return self
+    }
+
+    func returnNumber(n: Int) -> Int {
+      return n
+    }
+    static func returnNumberStatic(n: Int) -> Int {
+      return n
+    }
+  }
+
+  let exist: OptionalRequirements = Class()
+  let existMeta: OptionalRequirements.Type = Class.self
+
+  let returnNumberRef = exist.returnNumber
+  let returnNumberStaticRef = existMeta.returnNumberStatic
+  let returnNumberUnboundRef = OptionalRequirements.returnNumber
+
+  expectEqual(returnNumberRef!(123), 123)
+  expectEqual(returnNumberStaticRef!(456), 456)
+  expectEqual(returnNumberUnboundRef(exist)!(789), 789)
+
+  let returnSelfRef = exist.returnSelf
+  let returnSelfUnboundRef = OptionalRequirements.returnSelf
+
+  expectEqual(returnSelfRef!().returnNumber!(n: 321), 321)
+  expectEqual(returnSelfUnboundRef(exist)!().returnNumber!(n: 456), 456)
+}
+
 runAllTests()