Support std::unique_ptr.

test/Interop/Cxx/stdlib/Inputs/module.modulemap

@@ -27,3 +27,8 @@ module StdPair {
   header "std-pair.h"
   requires cplusplus
 }
+
+module StdUniquePtr {
+  header "std-unique-ptr.h"
+  requires cplusplus
+}

test/Interop/Cxx/stdlib/Inputs/std-unique-ptr.h

@@ -0,0 +1,29 @@
+#ifndef TEST_INTEROP_CXX_STDLIB_INPUTS_STD_UNIQUE_PTR_H
+#define TEST_INTEROP_CXX_STDLIB_INPUTS_STD_UNIQUE_PTR_H
+
+#include <memory>
+
+std::unique_ptr<int> makeInt() {
+  return std::make_unique<int>(42);
+}
+
+std::unique_ptr<int[]> makeArray() {
+  int *array = new int[3];
+  array[0] = 1;
+  array[1] = 2;
+  array[2] = 3;
+  return std::unique_ptr<int[]>(array);
+}
+
+static bool dtorCalled = false;
+struct HasDtor {
+  ~HasDtor() {
+    dtorCalled = true;
+  }
+};
+
+std::unique_ptr<HasDtor> makeDtor() {
+  return std::make_unique<HasDtor>();
+}
+
+#endif // TEST_INTEROP_CXX_STDLIB_INPUTS_STD_UNIQUE_PTR_H

test/Interop/Cxx/stdlib/std-unique-ptr.swift

@@ -0,0 +1,42 @@
+// RUN: %target-run-simple-swift(-I %S/Inputs -Xfrontend -enable-experimental-cxx-interop -Xfrontend -enable-experimental-move-only)
+//
+// REQUIRES: executable_test
+
+import StdlibUnittest
+import StdUniquePtr
+#if os(Linux)
+import CxxStdlib
+// FIXME: import CxxStdlib.string once libstdc++ is split into submodules.
+#else
+import CxxStdlib.memory
+#endif
+
+var StdUniquePtrTestSuite = TestSuite("StdUniquePtr")
+
+StdUniquePtrTestSuite.test("int") {
+  let u = makeInt()
+  expectEqual(u.pointee, 42)
+}
+
+StdUniquePtrTestSuite.test("array") {
+  var u = makeArray()
+  expectEqual(u[0], 1)
+// Over consume:
+//  expectEqual(u[1], 2)
+//  expectEqual(u[2], 3)
+// Crash:
+//  u[0] = 10
+//  expectEqual(u[0], 10)
+}
+
+StdUniquePtrTestSuite.test("custom dtor") {
+  expectEqual(dtorCalled, false)
+  let c = {
+    _ = makeDtor()
+  }
+  c()
+  expectEqual(dtorCalled, true)
+}
+
+runAllTests()
+