C++ Interop: add tests for extensions of C++ classes

Author: egorzhdan

test/Interop/Cxx/class/Inputs/extensions.h

@@ -0,0 +1,14 @@
+#ifndef TEST_INTEROP_CXX_CLASS_INPUTS_EXTENSIONS_H
+#define TEST_INTEROP_CXX_CLASS_INPUTS_EXTENSIONS_H
+
+namespace Outer {
+namespace Space {
+
+struct Foo {
+  int a;
+};
+
+}
+}
+
+#endif //TEST_INTEROP_CXX_CLASS_INPUTS_EXTENSIONS_H

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

@@ -23,6 +23,11 @@ module Destructors {
   requires cplusplus
 }
 
+module Extensions {
+  header "extensions.h"
+  requires cplusplus
+}
+
 module LoadableTypes {
   header "loadable-types.h"
   requires cplusplus

test/Interop/Cxx/class/extensions-executable.swift

@@ -0,0 +1,18 @@
+// RUN: %target-run-simple-swift(-I %S/Inputs/ -Xfrontend -enable-cxx-interop)
+// REQUIRES: executable_test
+
+import StdlibUnittest
+import Extensions
+
+var CxxClassExtensionsTestSuite = TestSuite("CxxClassExtensions")
+
+extension Outer.Space.Foo {
+  func bar() -> Int32 { return a + 1 }
+}
+
+CxxClassExtensionsTestSuite.test("calling extension method") {
+  var foo = Outer.Space.Foo(a: 123)
+  expectEqual(124, foo.bar())
+}
+
+runAllTests()

test/Interop/Cxx/class/extensions-irgen.swift

@@ -0,0 +1,16 @@
+// RUN: %target-swift-emit-ir %s -I %S/Inputs -enable-cxx-interop | %FileCheck %s
+//
+// We can't yet call member functions correctly on Windows (SR-13129).
+// XFAIL: OS=windows-msvc
+
+import Extensions
+
+extension Outer.Space.Foo {
+  func foo() {}
+}
+
+Outer.Space.Foo().foo()
+
+// CHECK: call swiftcc void @"$sSo5OuterO5SpaceO10ExtensionsE3FooV4mainE3fooyyF"
+
+// CHECK: define hidden swiftcc void @"$sSo5OuterO5SpaceO10ExtensionsE3FooV4mainE3fooyyF"

test/Interop/Cxx/class/extensions-typechecker.swift

@@ -0,0 +1,16 @@
+// RUN: %target-typecheck-verify-swift -I %S/Inputs -enable-cxx-interop
+
+import Extensions
+
+extension Outer.Space.Foo {
+  func bar() -> Int32 { return a }
+}
+
+extension Outer.Space.Foo: ExpressibleByIntegerLiteral {
+  public init(integerLiteral value: IntegerLiteralType) {
+    self.init(a: Int32(value))
+  }
+}
+
+var it: Outer.Space.Foo = 123
+let res = it.bar()