2 files changed, 87 insertions, 2 deletions
diff --git a/clang/lib/AST/DeclObjC.cpp b/clang/lib/AST/DeclObjC.cpp
index a313acf2007..d873ad0746b 100644
--- a/clang/lib/AST/DeclObjC.cpp
+++ b/clang/lib/AST/DeclObjC.cpp
@@ -716,6 +716,60 @@ ObjCMethodDecl *ObjCImplementationDecl::getClassMethod(Selector Sel) const {
   return NULL;
 }
 
+/// FindPropertyImplDecl - This method looks up a previous ObjCPropertyImplDecl
+/// added to the list of those properties @synthesized/@dynamic in this
+/// @implementation block.
+///
+ObjCPropertyImplDecl *ObjCImplementationDecl::FindPropertyImplDecl(IdentifierInfo *Id) const {
+  for (propimpl_iterator i = propimpl_begin(), e = propimpl_end(); i != e; ++i) {
+    ObjCPropertyImplDecl *PID = *i;
+    if (PID->getPropertyDecl()->getIdentifier() == Id)
+      return PID;
+  }
+  return 0;
+}
+
+/// FindPropertyImplIvarDecl - This method lookup the ivar in the list of
+/// properties implemented in this @implementation block and returns it if 
+/// found.
+///
+ObjCPropertyImplDecl *ObjCImplementationDecl::FindPropertyImplIvarDecl(IdentifierInfo *ivarId) const {
+  for (propimpl_iterator i = propimpl_begin(), e = propimpl_end(); i != e; ++i) {
+    ObjCPropertyImplDecl *PID = *i;
+    if (PID->getPropertyIvarDecl() &&
+        PID->getPropertyIvarDecl()->getIdentifier() == ivarId)
+      return PID;
+  }
+  return 0;
+}
+
+/// FindPropertyImplIvarDecl - This method lookup the ivar in the list of
+/// properties implemented in this category @implementation block and returns it if 
+/// found.
+///
+ObjCPropertyImplDecl *ObjCCategoryImplDecl::FindPropertyImplIvarDecl(IdentifierInfo *ivarId) const {
+  for (propimpl_iterator i = propimpl_begin(), e = propimpl_end(); i != e; ++i) {
+    ObjCPropertyImplDecl *PID = *i;
+    if (PID->getPropertyIvarDecl() &&
+        PID->getPropertyIvarDecl()->getIdentifier() == ivarId)
+      return PID;
+  }
+  return 0;
+}
+
+/// FindPropertyImplDecl - This method looks up a previous ObjCPropertyImplDecl
+/// added to the list of those properties @synthesized/@dynamic in this
+/// category @implementation block.
+///
+ObjCPropertyImplDecl *ObjCCategoryImplDecl::FindPropertyImplDecl(IdentifierInfo *Id) const {
+  for (propimpl_iterator i = propimpl_begin(), e = propimpl_end(); i != e; ++i) {
+    ObjCPropertyImplDecl *PID = *i;
+    if (PID->getPropertyDecl()->getIdentifier() == Id)
+      return PID;
+  }
+  return 0;
+}
+
 // lookupInstanceMethod - This method returns an instance method by looking in
 // the class implementation. Unlike interfaces, we don't look outside the
 // implementation.
diff --git a/clang/lib/Sema/SemaDeclObjC.cpp b/clang/lib/Sema/SemaDeclObjC.cpp
index a58d1da6322..03c803054ca 100644
--- a/clang/lib/Sema/SemaDeclObjC.cpp
+++ b/clang/lib/Sema/SemaDeclObjC.cpp
@@ -1506,10 +1506,41 @@ Sema::DeclTy *Sema::ActOnPropertyImplDecl(SourceLocation AtLoc,
                                   ObjCPropertyImplDecl::Synthesize 
                                   : ObjCPropertyImplDecl::Dynamic),
                                  Ivar);
-  if (IC)
+  if (IC) {
+    if (Synthesize)
+      if (ObjCPropertyImplDecl *PPIDecl = 
+          IC->FindPropertyImplIvarDecl(PropertyIvar)) {
+        Diag(PropertyLoc, diag::error_duplicate_ivar_use) 
+          << PropertyId << PPIDecl->getPropertyDecl()->getIdentifier() 
+          << PropertyIvar;
+        Diag(PPIDecl->getLocation(), diag::note_previous_use);
+      }
+    
+    if (ObjCPropertyImplDecl *PPIDecl = IC->FindPropertyImplDecl(PropertyId)) {
+      Diag(PropertyLoc, diag::error_property_implemented) << PropertyId;
+      Diag(PPIDecl->getLocation(), diag::note_previous_declaration);
+      return 0;
+    }
     IC->addPropertyImplementation(PIDecl);
-  else
+  }
+  else {
+    if (Synthesize)
+      if (ObjCPropertyImplDecl *PPIDecl = 
+          CatImplClass->FindPropertyImplIvarDecl(PropertyIvar)) {
+        Diag(PropertyLoc, diag::error_duplicate_ivar_use) 
+          << PropertyId << PPIDecl->getPropertyDecl()->getIdentifier() 
+          << PropertyIvar;
+        Diag(PPIDecl->getLocation(), diag::note_previous_use);
+      }
+    
+    if (ObjCPropertyImplDecl *PPIDecl = 
+          CatImplClass->FindPropertyImplDecl(PropertyId)) {
+      Diag(PropertyLoc, diag::error_property_implemented) << PropertyId;
+      Diag(PPIDecl->getLocation(), diag::note_previous_declaration);
+      return 0;
+    }    
     CatImplClass->addPropertyImplementation(PIDecl);
+  }
     
   return PIDecl;
 }