Refactoring the C++ thunk to directly return the Swift::Expected intead od the SWIFT_RETURN_THUNK macro

Author: Robertorosmaninho

Diff for: lib/PrintAsClang/PrintClangFunction.cpp

@@ -1248,22 +1248,22 @@ void DeclAndTypeClangFunctionPrinter::printCxxThunkBody(
     os << "    throw (Swift::Error(opaqueError));\n";
     os << "#else\n";
     if (resultTy->isVoid()) {
-      os << "    return SWIFT_RETURN_THUNK(void, Swift::Error(opaqueError));\n";
+      os << "    return Swift::Expected<void>(Swift::Error(opaqueError));\n";
       os << "#endif\n";
     } else {
       auto directResultType = signature.getDirectResultType();
       printDirectReturnOrParamCType(
           *directResultType, resultTy, moduleContext, os, cPrologueOS,
           typeMapping, interopContext, [&]() {
-            os << "    return SWIFT_RETURN_THUNK(";
+            os << "    return Swift::Expected<";
             OptionalTypeKind retKind;
             Type objTy;
             std::tie(objTy, retKind) =
                 DeclAndTypePrinter::getObjectTypeAndOptionality(FD, resultTy);
 
             auto s = printClangFunctionReturnType(objTy, retKind, const_cast<ModuleDecl *>(moduleContext),
                                                   OutputLanguageMode::Cxx);
-            os << ", Swift::Error(opaqueError));\n";
+            os << ">(Swift::Error(opaqueError));\n";
             os << "#endif\n";
 
             // Return the function result value if it doesn't throw.

Diff for: test/Interop/SwiftToCxx/functions/swift-functions-errors.swift

@@ -38,7 +38,7 @@ public func emptyThrowFunction() throws { print("passEmptyThrowFunction") }
 // CHECK: #ifdef __cpp_exceptions
 // CHECK: throw (Swift::Error(opaqueError));
 // CHECK: #else
-// CHECK: return SWIFT_RETURN_THUNK(void, Swift::Error(opaqueError));
+// CHECK: return Swift::Expected<void>(Swift::Error(opaqueError));
 // CHECK: #endif
 // CHECK: }
 
@@ -64,7 +64,7 @@ public func testDestroyedError() throws { throw DestroyedError() }
 // CHECK: #ifdef __cpp_exceptions
 // CHECK: throw (Swift::Error(opaqueError));
 // CHECK: #else
-// CHECK: return SWIFT_RETURN_THUNK(void, Swift::Error(opaqueError));
+// CHECK: return Swift::Expected<void>(Swift::Error(opaqueError));
 // CHECK: #endif
 // CHECK: }
 
@@ -82,7 +82,7 @@ public func throwFunction() throws {
 // CHECK: #ifdef __cpp_exceptions
 // CHECK: throw (Swift::Error(opaqueError));
 // CHECK: #else
-// CHECK: return SWIFT_RETURN_THUNK(void, Swift::Error(opaqueError));
+// CHECK: return Swift::Expected<void>(Swift::Error(opaqueError));
 // CHECK: #endif
 // CHECK: }
 
@@ -103,7 +103,7 @@ public func throwFunctionWithPossibleReturn(_ a: Int) throws -> Int {
 // CHECK: #ifdef __cpp_exceptions
 // CHECK: throw (Swift::Error(opaqueError));
 // CHECK: #else
-// CHECK: return SWIFT_RETURN_THUNK(swift::Int, Swift::Error(opaqueError));
+// CHECK: return Swift::Expected<swift::Int>(Swift::Error(opaqueError));
 // CHECK: #endif
 // CHECK: return SWIFT_RETURN_THUNK(swift::Int, returnValue);
 // CHECK: }
@@ -122,7 +122,7 @@ public func throwFunctionWithReturn() throws -> Int {
 // CHECK: #ifdef __cpp_exceptions
 // CHECK: throw (Swift::Error(opaqueError));
 // CHECK: #else
-// CHECK: return SWIFT_RETURN_THUNK(swift::Int, Swift::Error(opaqueError));
+// CHECK: return Swift::Expected<swift::Int>(Swift::Error(opaqueError));
 // CHECK: #endif
 // CHECK: return SWIFT_RETURN_THUNK(swift::Int, returnValue);
 // CHECK: }