From 1f1b08463ee3a13e3ce85678216e4546eb85c0ff Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Wed, 18 Dec 2013 21:46:16 +0000
Subject: [PATCH] Allow Objective-C pointer conversions following an explicit
 user conversion.

Finishes the work started in r194224, and fixes <rdar://problem/15494681>.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@197609 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/clang/Sema/Sema.h                   |  4 ++--
 lib/Sema/SemaInit.cpp                       | 12 ++++++++----
 test/SemaObjCXX/contextual-convert-to-id.mm | 19 +++++++++++++++++++
 3 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index 0e4ab07af0..75e1a341ed 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -2162,13 +2162,13 @@ public:
                               CXXRecordDecl *ActingContext,
                               Expr *From, QualType ToType,
                               OverloadCandidateSet& CandidateSet,
-                              bool AllowObjCConversionOnExplicit = false);
+                              bool AllowObjCConversionOnExplicit);
   void AddTemplateConversionCandidate(FunctionTemplateDecl *FunctionTemplate,
                                       DeclAccessPair FoundDecl,
                                       CXXRecordDecl *ActingContext,
                                       Expr *From, QualType ToType,
                                       OverloadCandidateSet &CandidateSet,
-                                    bool AllowObjCConversionOnExplicit = false);
+                                      bool AllowObjCConversionOnExplicit);
   void AddSurrogateCandidate(CXXConversionDecl *Conversion,
                              DeclAccessPair FoundDecl,
                              CXXRecordDecl *ActingContext,
diff --git a/lib/Sema/SemaInit.cpp b/lib/Sema/SemaInit.cpp
index 9ba873a078..ae0f662562 100644
--- a/lib/Sema/SemaInit.cpp
+++ b/lib/Sema/SemaInit.cpp
@@ -3522,10 +3522,13 @@ static OverloadingResult TryRefInitWithConversionFunction(Sema &S,
         if (ConvTemplate)
           S.AddTemplateConversionCandidate(ConvTemplate, I.getPair(),
                                            ActingDC, Initializer,
-                                           DestType, CandidateSet);
+                                           DestType, CandidateSet,
+                                           /*AllowObjCConversionOnExplicit=*/
+                                             false);
         else
           S.AddConversionCandidate(Conv, I.getPair(), ActingDC,
-                                   Initializer, DestType, CandidateSet);
+                                   Initializer, DestType, CandidateSet,
+                                   /*AllowObjCConversionOnExplicit=*/false);
       }
     }
   }
@@ -4145,10 +4148,11 @@ static void TryUserDefinedConversion(Sema &S,
           if (ConvTemplate)
             S.AddTemplateConversionCandidate(ConvTemplate, I.getPair(),
                                              ActingDC, Initializer, DestType,
-                                             CandidateSet);
+                                             CandidateSet, AllowExplicit);
           else
             S.AddConversionCandidate(Conv, I.getPair(), ActingDC,
-                                     Initializer, DestType, CandidateSet);
+                                     Initializer, DestType, CandidateSet,
+                                     AllowExplicit);
         }
       }
     }
diff --git a/test/SemaObjCXX/contextual-convert-to-id.mm b/test/SemaObjCXX/contextual-convert-to-id.mm
index 602d6c24a8..47a9d07d41 100644
--- a/test/SemaObjCXX/contextual-convert-to-id.mm
+++ b/test/SemaObjCXX/contextual-convert-to-id.mm
@@ -8,6 +8,10 @@
 - unknownMethod;
 @end
 
+@interface C : A
+- knownMethod;
+@end
+
 template<typename T> struct RetainPtr {
   explicit operator T*() const;
 };
@@ -17,6 +21,16 @@ void methodCallToSpecific(RetainPtr<A> a) {
   [a unknownMethod]; // expected-warning{{'A' may not respond to 'unknownMethod'}}
 }
 
+void explicitCast(RetainPtr<A> a, RetainPtr<B> b, RetainPtr<C> c) {
+  (void)(A*)a;
+  (void)(A*)b; // expected-error{{cannot convert 'RetainPtr<B>' to 'A *' without a conversion operator}}
+  (void)(A*)c;
+  (void)(C*)a;
+  (void)static_cast<A*>(a);
+  (void)static_cast<A*>(b);  // expected-error{{cannot convert 'RetainPtr<B>' to 'A *' without a conversion operator}}
+  (void)static_cast<A*>(c);
+}
+
 struct Incomplete; // expected-note{{forward declaration}}
 
 void methodCallToIncomplete(Incomplete &incomplete) {
@@ -31,3 +45,8 @@ void methodCallToId(IdPtr a) {
   [a knownMethod];
   [a unknownMethod];
 }
+
+void explicitCast(IdPtr a) {
+  (void)(A*)a;
+  (void)static_cast<A*>(a);
+}
-- 
2.40.0