Merge pull request swiftlang#74822 from swiftlang/egorzhdan/frt-safety-heuristic-test

[cxx-interop] Add tests for methods of reference types returning reference types

Author: egorzhdan

test/Interop/Cxx/foreign-reference/Inputs/pod.h

@@ -47,6 +47,8 @@ __attribute__((swift_attr("release:immortal"))) IntPair {
   int test() const { return b - a; }
   int testMutable() { return b - a; }
 
+  IntPair &instancePassThroughByRef(IntPair& ref) { return ref; }
+  static IntPair &staticPassThroughByRef(IntPair& ref) { return ref; }
   static IntPair *create() { return new (malloc(sizeof(IntPair))) IntPair(); }
 };
 
@@ -55,6 +57,7 @@ void mutateIt(IntPair &x) {
   x.b = 4;
 }
 IntPair passThroughByValue(IntPair x) { return x; }
+IntPair &passThroughByRef(IntPair &x) { return x; }
 
 struct __attribute__((swift_attr("import_reference")))
 __attribute__((swift_attr("retain:immortal")))
@@ -118,6 +121,17 @@ struct ValueHoldingPair {
   }
 };
 
+struct ValueHoldingPairRef {
+  IntPair &pair = *IntPair::create();
+
+  int sub(const IntPair &other) const {
+    return pair.test() - other.test();
+  };
+  const IntPair &max(const IntPair &other) const {
+    return pair.test() > other.test() ? pair : other;
+  };
+};
+
 struct __attribute__((swift_attr("import_reference")))
 __attribute__((swift_attr("retain:immortal")))
 __attribute__((swift_attr("release:immortal"))) BigType {

test/Interop/Cxx/foreign-reference/pod-module-interface.swift

@@ -24,12 +24,15 @@
 // CHECK-NOT: init
 // CHECK:   func test() -> Int32
 // CHECK:   func testMutable() -> Int32
+// CHECK:   func instancePassThroughByRef(_ ref: IntPair) -> IntPair
+// CHECK:   class func staticPassThroughByRef(_ ref: IntPair) -> IntPair
 // CHECK:   class func create() -> IntPair
 // CHECK:   var a: Int32
 // CHECK:   var b: Int32
 // CHECK: }
 // CHECK: func mutateIt(_ x: IntPair)
 // CHECK-NOT: func passThroughByValue(_ x: IntPair) -> IntPair
+// CHECK: func passThroughByRef(_ x: IntPair) -> IntPair
 
 // CHECK: class RefHoldingPair {
 // CHECK-NOT: init
@@ -68,6 +71,13 @@
 // CHECK:   var otherValue: Int32
 // CHECK: }
 
+// CHECK: struct ValueHoldingPairRef {
+// CHECK-NOT: pair
+// CHECK:   init()
+// CHECK:   func sub(_ other: IntPair) -> Int32
+// CHECK:   func max(_ other: IntPair) -> IntPair
+// CHECK: }
+
 // CHECK: class BigType {
 // CHECK-NOT: init
 // CHECK:   func test() -> Int32

test/Interop/Cxx/foreign-reference/pod.swift

@@ -114,6 +114,16 @@ PODTestSuite.test("RefHoldingPairPtr") {
   expectEqual(x.test(), 41)
 }
 
+PODTestSuite.test("ValueHoldingPairRef") {
+  let x = ValueHoldingPairRef()
+  expectEqual(x.pair.test(), 1)
+
+  let pair2 = IntPair.create()
+  pair2.b = 123
+  expectEqual(x.sub(pair2), -121)
+  expectEqual(x.max(pair2).test(), pair2.test())
+}
+
 PODTestSuite.test("StructHoldingPair") {
   var x = StructHoldingPair(pair: IntPair.create())
   expectEqual(x.pair.test(), 1)