From: Douglas Gregor <dgregor@apple.com>
Date: Tue, 26 Jul 2011 14:53:44 +0000 (+0000)
Subject: Objective-C++ ARC: When performing template argument deduction for a
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=da8b24961acfbeff47f585109b7559ba60e574cb;p=clang

Objective-C++ ARC: When performing template argument deduction for a
lifetime-qualified template parameter, ensure that the deduced
template argument is a lifetime type. Fixes <rdar://problem/9828157>.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@136078 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Sema/SemaTemplateDeduction.cpp b/lib/Sema/SemaTemplateDeduction.cpp
index 888d3bee5f..824b9d9abb 100644
--- a/lib/Sema/SemaTemplateDeduction.cpp
+++ b/lib/Sema/SemaTemplateDeduction.cpp
@@ -1017,6 +1017,17 @@ DeduceTemplateArguments(Sema &S,
     if (ParamQs.hasObjCLifetime())
       DeducedQs.removeObjCLifetime();
     
+    // Objective-C ARC:
+    //   If template deduction would produce a lifetime qualifier on a type
+    //   that is not a lifetime type, template argument deduction fails.
+    if (ParamQs.hasObjCLifetime() && !DeducedType->isObjCLifetimeType() &&
+        !DeducedType->isDependentType()) {
+      Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index));
+      Info.FirstArg = TemplateArgument(Param);
+      Info.SecondArg = TemplateArgument(Arg);
+      return Sema::TDK_Underqualified;      
+    }
+    
     // Objective-C ARC:
     //   If template deduction would produce an argument type with lifetime type
     //   but no lifetime qualifier, the __strong lifetime qualifier is inferred.
diff --git a/test/SemaObjCXX/arc-templates.mm b/test/SemaObjCXX/arc-templates.mm
index fa4e0a7776..7b0e6472c7 100644
--- a/test/SemaObjCXX/arc-templates.mm
+++ b/test/SemaObjCXX/arc-templates.mm
@@ -252,3 +252,17 @@ void test_qual_vs_unqual_a() {
   float &fr3 = qual_vs_unqual_ref(*aap);
   float &fr4 = qual_vs_unqual_ref(*uap);
 }
+
+namespace rdar9828157 {
+  // Template argument deduction involving lifetime qualifiers and
+  // non-lifetime types.
+  class A { };
+
+  template<typename T> float& f(T&);
+  template<typename T> int& f(__strong T&);
+  template<typename T> double& f(__weak T&);
+
+  void test_f(A* ap) {
+    float &fr = (f)(ap);  
+  }
+}