From 92d1387ca9a1b2becdf7d72e0111872cff135197 Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Thu, 17 Jan 2013 23:59:28 +0000
Subject: [PATCH] One can override an Objective-C ARC ownership qualifier that
 came from a template parameter; make that also include one that came from
 'auto'. Fixes <rdar://problem/12078752>.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@172770 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Sema/TreeTransform.h  | 10 ++++++++++
 test/SemaObjCXX/arc-0x.mm |  8 ++++++++
 2 files changed, 18 insertions(+)

diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index 2091cffc83..bacf6d5d9b 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -3365,6 +3365,7 @@ TreeTransform<Derived>::TransformQualifiedType(TypeLocBuilder &TLB,
       // Objective-C ARC:
       //   A lifetime qualifier applied to a substituted template parameter
       //   overrides the lifetime qualifier from the template argument.
+      const AutoType *AutoTy;
       if (const SubstTemplateTypeParmType *SubstTypeParam
                                 = dyn_cast<SubstTemplateTypeParmType>(Result)) {
         QualType Replacement = SubstTypeParam->getReplacementType();
@@ -3377,6 +3378,15 @@ TreeTransform<Derived>::TransformQualifiedType(TypeLocBuilder &TLB,
                                         SubstTypeParam->getReplacedParameter(),
                                                               Replacement);
         TLB.TypeWasModifiedSafely(Result);
+      } else if ((AutoTy = dyn_cast<AutoType>(Result)) && AutoTy->isDeduced()) {
+        // 'auto' types behave the same way as template parameters.
+        QualType Deduced = AutoTy->getDeducedType();
+        Qualifiers Qs = Deduced.getQualifiers();
+        Qs.removeObjCLifetime();
+        Deduced = SemaRef.Context.getQualifiedType(Deduced.getUnqualifiedType(),
+                                                   Qs);
+        Result = SemaRef.Context.getAutoType(Deduced);
+        TLB.TypeWasModifiedSafely(Result);
       } else {
         // Otherwise, complain about the addition of a qualifier to an
         // already-qualified type.
diff --git a/test/SemaObjCXX/arc-0x.mm b/test/SemaObjCXX/arc-0x.mm
index 43f6671ac2..391fc47f34 100644
--- a/test/SemaObjCXX/arc-0x.mm
+++ b/test/SemaObjCXX/arc-0x.mm
@@ -93,3 +93,11 @@ typedef __builtin_va_list va_list;
     __builtin_va_arg(args, id);
 }
 @end
+
+namespace rdar12078752 {
+  void f() {
+    NSObject* o =0;
+    __autoreleasing decltype(o) o2 = o;
+    __autoreleasing auto o3 = o;
+  }
+}
-- 
2.40.0