From 496e8b345c21329608b2998038db3508896a66ad Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Fri, 7 May 2010 19:42:26 +0000
Subject: [PATCH] Reapply the reference-binding patch applied below, along with
 a fix to ensure that we complete the type when we need to look at
 constructors during reference binding.

When determining whether the two types involved in reference binding
are reference-compatible, reference-related, etc., do not complete the
type of the reference itself because it is not necessary to determine
well-formedness of the program. Complete the type that we are binding
to, since that can affect whether we know about a derived-to-base
conversion.

Re-fixes PR7080.

llvm-svn: 103283
---
 clang/lib/Sema/SemaInit.cpp                   |  8 +++++---
 clang/lib/Sema/SemaOverload.cpp               |  3 +--
 .../SemaTemplate/instantiate-complete.cpp     | 20 +++++++++++++++++++
 3 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 0360b3d96566..b2f416ca3749 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -2245,11 +2245,11 @@ static OverloadingResult TryRefInitWithConversionFunction(Sema &S,
   bool AllowExplicit = Kind.getKind() == InitializationKind::IK_Direct;
   
   const RecordType *T1RecordType = 0;
-  if (AllowRValues && (T1RecordType = T1->getAs<RecordType>())) {
+  if (AllowRValues && (T1RecordType = T1->getAs<RecordType>()) &&
+      !S.RequireCompleteType(Kind.getLocation(), T1, 0)) {
     // The type we're converting to is a class type. Enumerate its constructors
     // to see if there is a suitable conversion.
     CXXRecordDecl *T1RecordDecl = cast<CXXRecordDecl>(T1RecordType->getDecl());
-    
     DeclarationName ConstructorName
       = S.Context.DeclarationNames.getCXXConstructorName(
                            S.Context.getCanonicalType(T1).getUnqualifiedType());
@@ -2281,7 +2281,9 @@ static OverloadingResult TryRefInitWithConversionFunction(Sema &S,
     }    
   }
   
-  if (const RecordType *T2RecordType = T2->getAs<RecordType>()) {
+  const RecordType *T2RecordType = 0;
+  if ((T2RecordType = T2->getAs<RecordType>()) &&
+      !S.RequireCompleteType(Kind.getLocation(), T2, 0)) {
     // The type we're converting from is a class type, enumerate its conversion
     // functions.
     CXXRecordDecl *T2RecordDecl = cast<CXXRecordDecl>(T2RecordType->getDecl());
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index 531ca39a996d..dec9854c72eb 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -2289,8 +2289,7 @@ Sema::CompareReferenceRelationship(SourceLocation Loc,
   //   T1 is a base class of T2.
   if (UnqualT1 == UnqualT2)
     DerivedToBase = false;
-  else if (!RequireCompleteType(Loc, OrigT1, PDiag()) &&
-           !RequireCompleteType(Loc, OrigT2, PDiag()) &&
+  else if (!RequireCompleteType(Loc, OrigT2, PDiag()) &&
            IsDerivedFrom(UnqualT2, UnqualT1))
     DerivedToBase = true;
   else
diff --git a/clang/test/SemaTemplate/instantiate-complete.cpp b/clang/test/SemaTemplate/instantiate-complete.cpp
index d854c9e6aacc..a2cb04917327 100644
--- a/clang/test/SemaTemplate/instantiate-complete.cpp
+++ b/clang/test/SemaTemplate/instantiate-complete.cpp
@@ -99,3 +99,23 @@ namespace TemporaryObjectCopy {
 
   template void f(int);
 }
+
+namespace PR7080 {
+  template <class T, class U>
+  class X
+  {
+    typedef char true_t;
+    class false_t { char dummy[2]; };
+    static true_t dispatch(U);
+    static false_t dispatch(...);
+    static T trigger();
+  public:
+    enum { value = sizeof(dispatch(trigger())) == sizeof(true_t) };
+  };
+
+  template <class T>
+  class rv : public T
+  { };
+
+  bool x = X<int, rv<int>&>::value;
+}