From 3df768796aad080a71846c6614f81a35548b9381 Mon Sep 17 00:00:00 2001
From: Lang Hames <lhames@gmail.com>
Date: Thu, 30 Jun 2016 17:43:06 +0000
Subject: [PATCH] [Support] Fix a bug in ErrorList::join / joinErrors.

When concatenating two error lists the ErrorList::join method (which is called
by joinErrors) was failing to set the checked bit on the second error, leading
to a 'failure to check error' assertion.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@274249 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Support/Error.h    |  3 ++-
 unittests/Support/ErrorTest.cpp | 45 +++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/include/llvm/Support/Error.h b/include/llvm/Support/Error.h
index b817a230d0d..8206eed67d3 100644
--- a/include/llvm/Support/Error.h
+++ b/include/llvm/Support/Error.h
@@ -345,7 +345,8 @@ private:
     if (E1.isA<ErrorList>()) {
       auto &E1List = static_cast<ErrorList &>(*E1.getPtr());
       if (E2.isA<ErrorList>()) {
-        auto &E2List = static_cast<ErrorList &>(*E2.getPtr());
+        auto E2Payload = E2.takePayload();
+        auto &E2List = static_cast<ErrorList &>(*E2Payload);
         for (auto &Payload : E2List.Payloads)
           E1List.Payloads.push_back(std::move(Payload));
       } else
diff --git a/unittests/Support/ErrorTest.cpp b/unittests/Support/ErrorTest.cpp
index d5d799384f4..20509268374 100644
--- a/unittests/Support/ErrorTest.cpp
+++ b/unittests/Support/ErrorTest.cpp
@@ -314,6 +314,51 @@ TEST(Error, CheckJoinErrors) {
   EXPECT_TRUE(CustomErrorInfo1 == 7 && CustomErrorInfo2 == 42 &&
               CustomErrorExtraInfo == 7)
       << "Failed handling compound Error.";
+
+  // Test appending a single item to a list.
+  {
+    int Sum = 0;
+    handleAllErrors(
+        joinErrors(
+            joinErrors(make_error<CustomError>(7),
+                       make_error<CustomError>(7)),
+            make_error<CustomError>(7)),
+        [&](const CustomError &CE) {
+          Sum += CE.getInfo();
+        });
+    EXPECT_EQ(Sum, 21) << "Failed to correctly append error to error list.";
+  }
+
+  // Test prepending a single item to a list.
+  {
+    int Sum = 0;
+    handleAllErrors(
+        joinErrors(
+            make_error<CustomError>(7),
+            joinErrors(make_error<CustomError>(7),
+                       make_error<CustomError>(7))),
+        [&](const CustomError &CE) {
+          Sum += CE.getInfo();
+        });
+    EXPECT_EQ(Sum, 21) << "Failed to correctly prepend error to error list.";
+  }
+
+  // Test concatenating two error lists.
+  {
+    int Sum = 0;
+    handleAllErrors(
+        joinErrors(
+            joinErrors(
+                make_error<CustomError>(7),
+                make_error<CustomError>(7)),
+            joinErrors(
+                make_error<CustomError>(7),
+                make_error<CustomError>(7))),
+        [&](const CustomError &CE) {
+          Sum += CE.getInfo();
+        });
+    EXPECT_EQ(Sum, 28) << "Failed to correctly concatenate erorr lists.";
+  }
 }
 
 // Test that we can consume success values.