From 4ae5b7208ef72dec2a79d3d1c602cb47e9750d69 Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Sun, 5 Jun 2011 06:15:20 +0000
Subject: [PATCH] Identity and non-identity standard conversion sequences can
 be compared even when one is a reference binding and the other is not
 (<rdar://problem/9173984>), but the definition of an identity sequence does
 not involve lvalue-to-rvalue adjustments (PR9507). Fix both inter-related
 issues.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@132660 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/clang/Sema/Overload.h  |  3 +--
 lib/Sema/SemaOverload.cpp      | 10 ++++------
 test/SemaCXX/overload-call.cpp | 22 ++++++++++++++++++++++
 3 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/include/clang/Sema/Overload.h b/include/clang/Sema/Overload.h
index e196e83a0e..55931f2318 100644
--- a/include/clang/Sema/Overload.h
+++ b/include/clang/Sema/Overload.h
@@ -202,8 +202,7 @@ namespace clang {
     void setAsIdentityConversion();
     
     bool isIdentityConversion() const {
-      return First == ICK_Identity && Second == ICK_Identity && 
-             Third == ICK_Identity;
+      return Second == ICK_Identity && Third == ICK_Identity;
     }
     
     ImplicitConversionRank getRank() const;
diff --git a/lib/Sema/SemaOverload.cpp b/lib/Sema/SemaOverload.cpp
index e43c5fbbb5..eb1400cd57 100644
--- a/lib/Sema/SemaOverload.cpp
+++ b/lib/Sema/SemaOverload.cpp
@@ -2523,12 +2523,10 @@ compareStandardConversionSubsets(ASTContext &Context,
 
   // the identity conversion sequence is considered to be a subsequence of
   // any non-identity conversion sequence
-  if (SCS1.ReferenceBinding == SCS2.ReferenceBinding) {
-    if (SCS1.isIdentityConversion() && !SCS2.isIdentityConversion())
-      return ImplicitConversionSequence::Better;
-    else if (!SCS1.isIdentityConversion() && SCS2.isIdentityConversion())
-      return ImplicitConversionSequence::Worse;
-  }
+  if (SCS1.isIdentityConversion() && !SCS2.isIdentityConversion())
+    return ImplicitConversionSequence::Better;
+  else if (!SCS1.isIdentityConversion() && SCS2.isIdentityConversion())
+    return ImplicitConversionSequence::Worse;
 
   if (SCS1.Second != SCS2.Second) {
     if (SCS1.Second == ICK_Identity)
diff --git a/test/SemaCXX/overload-call.cpp b/test/SemaCXX/overload-call.cpp
index 81a88a3a9a..9cc48993fd 100644
--- a/test/SemaCXX/overload-call.cpp
+++ b/test/SemaCXX/overload-call.cpp
@@ -503,3 +503,25 @@ namespace rdar8499524 {
     g(W());
   }
 }
+
+namespace rdar9173984 {
+  template <typename T, unsigned long N> int &f(const T (&)[N]);
+  template <typename T> float &f(const T *);
+
+  void test() {
+    int arr[2] = {0, 0};
+    int *arrp = arr;
+    int &ir = f(arr);
+    float &fr = f(arrp);
+  }
+}
+
+namespace PR9507 {
+  void f(int * const&); // expected-note{{candidate function}}
+  void f(int const(&)[1]); // expected-note{{candidate function}}
+ 
+  int main() {
+    int n[1];
+    f(n); // expected-error{{call to 'f' is ambiguous}}
+  }
+}
-- 
2.40.0