[llvm] [orc-rt] Add testcase for Expected<Expected<T>> support. (PR #161660)

[Lang Hames via llvm-commits]

https://github.com/lhames created https://github.com/llvm/llvm-project/pull/161660

Follows addition of Expected<Error> support (99ce2062462), and has essentially the same motivation: supporting RPC calls to functions returning Expected<T>, where the RPC infrastructure wants to be able to wrap that result in its own Expected.

>From 846004d08191ed3c340dd214acd64ff8f1396a7b Mon Sep 17 00:00:00 2001
From: Lang Hames <lhames at gmail.com>
Date: Thu, 2 Oct 2025 22:49:22 +1000
Subject: [PATCH] [orc-rt] Add testcase for Expected<Expected<T>> support.

Follows addition of Expected<Error> support (99ce2062462), and has essentially
the same motivation: supporting RPC calls to functions returning Expected<T>,
where the RPC infrastructure wants to be able to wrap that result in its own
Expected.
---
 orc-rt/unittests/ErrorTest.cpp | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/orc-rt/unittests/ErrorTest.cpp b/orc-rt/unittests/ErrorTest.cpp
index 6b1fc1635b5b8..260b6afc2ae95 100644
--- a/orc-rt/unittests/ErrorTest.cpp
+++ b/orc-rt/unittests/ErrorTest.cpp
@@ -409,6 +409,31 @@ TEST(ErrorTest, ExpectedError) {
   }
 }
 
+// Test that Expected<Expected<T>> works as expected.
+TEST(ErrorTest, ExpectedExpected) {
+  {
+    // Test success-success case.
+    Expected<Expected<int>> E(Expected<int>(42), ForceExpectedSuccessValue());
+    EXPECT_TRUE(!!E);
+    cantFail(E.takeError());
+    auto EI = std::move(*E);
+    EXPECT_TRUE(!!EI);
+    cantFail(EI.takeError());
+    EXPECT_EQ(*EI, 42);
+  }
+
+  {
+    // Test "failure" success case.
+    Expected<Expected<int>> E(Expected<int>(make_error<StringError>("foo")),
+                              ForceExpectedSuccessValue());
+    EXPECT_TRUE(!!E);
+    cantFail(E.takeError());
+    auto EI = std::move(*E);
+    EXPECT_FALSE(!!EI);
+    EXPECT_EQ(toString(EI.takeError()), "foo");
+  }
+}
+
 // Test that the ExitOnError utility works as expected.
 TEST(ErrorTest, CantFailSuccess) {
   cantFail(Error::success());