3 files changed, 69 insertions, 13 deletions

diff --git a/include/clang/AST/ASTContext.h b/include/clang/AST/ASTContext.h
index d02fe9ffb7..b1842c9d42 100644
--- a/include/clang/AST/ASTContext.h
+++ b/include/clang/AST/ASTContext.h
@@ -27,6 +27,7 @@
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/FoldingSet.h"
 #include "llvm/ADT/OwningPtr.h"
+#include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/Support/Allocator.h"
 #include <vector>
 
@@ -890,7 +891,7 @@ public:
   unsigned CountSynthesizedIvars(const ObjCInterfaceDecl *OI);
   unsigned CountProtocolSynthesizedIvars(const ObjCProtocolDecl *PD);
   void CollectInheritedProtocols(const Decl *CDecl,
-                          llvm::SmallVectorImpl<ObjCProtocolDecl*> &Protocols);
+                          llvm::SmallPtrSet<ObjCProtocolDecl*, 8> &Protocols);
 
   //===--------------------------------------------------------------------===//
   //                            Type Operators
diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index 1112aa97b8..06a40728da 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -917,12 +917,12 @@ void ASTContext::CollectSynthesizedIvars(const ObjCInterfaceDecl *OI,
 /// CollectInheritedProtocols - Collect all protocols in current class and
 /// those inherited by it.
 void ASTContext::CollectInheritedProtocols(const Decl *CDecl,
-                          llvm::SmallVectorImpl<ObjCProtocolDecl*> &Protocols) {
+                          llvm::SmallPtrSet<ObjCProtocolDecl*, 8> &Protocols) {
   if (const ObjCInterfaceDecl *OI = dyn_cast<ObjCInterfaceDecl>(CDecl)) {
     for (ObjCInterfaceDecl::protocol_iterator P = OI->protocol_begin(),
          PE = OI->protocol_end(); P != PE; ++P) {
       ObjCProtocolDecl *Proto = (*P);
-      Protocols.push_back(Proto);
+      Protocols.insert(Proto);
       for (ObjCProtocolDecl::protocol_iterator P = Proto->protocol_begin(),
            PE = Proto->protocol_end(); P != PE; ++P)
         CollectInheritedProtocols(*P, Protocols);
@@ -943,7 +943,7 @@ void ASTContext::CollectInheritedProtocols(const Decl *CDecl,
     for (ObjCInterfaceDecl::protocol_iterator P = OC->protocol_begin(),
          PE = OC->protocol_end(); P != PE; ++P) {
       ObjCProtocolDecl *Proto = (*P);
-      Protocols.push_back(Proto);
+      Protocols.insert(Proto);
       for (ObjCProtocolDecl::protocol_iterator P = Proto->protocol_begin(),
            PE = Proto->protocol_end(); P != PE; ++P)
         CollectInheritedProtocols(*P, Protocols);
@@ -954,7 +954,7 @@ void ASTContext::CollectInheritedProtocols(const Decl *CDecl,
     for (ObjCProtocolDecl::protocol_iterator P = OP->protocol_begin(),
          PE = OP->protocol_end(); P != PE; ++P) {
       ObjCProtocolDecl *Proto = (*P);
-      Protocols.push_back(Proto);
+      Protocols.insert(Proto);
       for (ObjCProtocolDecl::protocol_iterator P = Proto->protocol_begin(),
            PE = Proto->protocol_end(); P != PE; ++P)
         CollectInheritedProtocols(*P, Protocols);
@@ -4188,8 +4188,8 @@ void getIntersectionOfProtocols(ASTContext &Context,
   if (LHSNumProtocols > 0)
     InheritedProtocolSet.insert(LHS->qual_begin(), LHS->qual_end());
   else {
-    llvm::SmallVector<ObjCProtocolDecl *, 8> LHSInheritedProtocols;
-     Context.CollectInheritedProtocols(LHS->getDecl(), LHSInheritedProtocols);
+    llvm::SmallPtrSet<ObjCProtocolDecl *, 8> LHSInheritedProtocols;
+    Context.CollectInheritedProtocols(LHS->getDecl(), LHSInheritedProtocols);
     InheritedProtocolSet.insert(LHSInheritedProtocols.begin(), 
                                 LHSInheritedProtocols.end());
   }
@@ -4202,13 +4202,13 @@ void getIntersectionOfProtocols(ASTContext &Context,
         IntersectionOfProtocols.push_back(RHSProtocols[i]);
   }
   else {
-    llvm::SmallVector<ObjCProtocolDecl *, 8> RHSInheritedProtocols;
+    llvm::SmallPtrSet<ObjCProtocolDecl *, 8> RHSInheritedProtocols;
     Context.CollectInheritedProtocols(RHS->getDecl(), RHSInheritedProtocols);
-    // FIXME. This may cause duplication of protocols in the list, but should
-    // be harmless.
-    for (unsigned i = 0, len = RHSInheritedProtocols.size(); i < len; ++i)
-      if (InheritedProtocolSet.count(RHSInheritedProtocols[i]))
-        IntersectionOfProtocols.push_back(RHSInheritedProtocols[i]);
+    for (llvm::SmallPtrSet<ObjCProtocolDecl*,8>::iterator I = 
+         RHSInheritedProtocols.begin(),
+         E = RHSInheritedProtocols.end(); I != E; ++I) 
+      if (InheritedProtocolSet.count((*I)))
+        IntersectionOfProtocols.push_back((*I));
   }
 }
 
diff --git a/test/SemaObjC/protocol-warn.m b/test/SemaObjC/protocol-warn.m
new file mode 100644
index 0000000000..d0c51e3ffa
--- /dev/null
+++ b/test/SemaObjC/protocol-warn.m
@@ -0,0 +1,55 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+// radar 7638810
+
+@protocol NSObject @end
+
+@interface NSObject <NSObject> @end
+
+@interface UIResponder : NSObject
+@end
+
+@implementation UIResponder
+@end
+
+@interface UIView : UIResponder
+@end
+
+@implementation UIView
+@end
+
+@interface UIWebTiledView : UIView
+@end
+
+@implementation UIWebTiledView
+@end
+
+@interface UIWebDocumentView : UIWebTiledView
+@end
+
+@implementation UIWebDocumentView
+@end
+
+@interface UIWebBrowserView : UIWebDocumentView
+@end
+
+@implementation UIWebBrowserView
+@end
+
+@interface UIPDFView : UIView
+@end
+
+@implementation UIPDFView
+@end
+
+@interface UIWebPDFView : UIPDFView
+@end
+
+@implementation UIWebPDFView
+@end
+
+UIWebPDFView *getView()
+{
+    UIWebBrowserView *browserView;
+    UIWebPDFView *pdfView;
+    return pdfView ? pdfView : browserView; // expected-warning {{incompatible pointer types returning 'UIView<NSObject> *', expected 'UIWebPDFView *'}}
+}