[TypeChecker] NFC: Add test-case for rdar://problem/42056741

(cherry picked from commit 939f6d4)

Author: xedin

test/Constraints/rdar42056741.swift

@@ -0,0 +1,23 @@
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -verify %s
+// REQUIRES: objc_interop
+
+import Foundation
+
+class A {
+  static var `default` = A()
+
+  func foo(arg: String) -> Bool {
+    return false
+  }
+
+  func foo(arg: String, _ flag: UnsafeMutablePointer<ObjCBool>?) -> Bool {
+    return true
+  }
+}
+
+class B {
+  var bar: Bool = false
+  func baz() {
+    bar = A.default.foo(arg: self.) // expected-error {{expected member name following '.'}}
+  }
+}

validation-test/IDE/crashers_2_fixed/0020-rdar42056741.swift

@@ -1,10 +1,8 @@
 // RUN: %target-swift-ide-test(mock-sdk: %clang-importer-sdk) -code-completion -code-completion-token=COMPLETE -source-filename=%s
-
 // REQUIRES: objc_interop
 
 import Foundation
 
-
 class A {
   static var `default` = A()