Objective-C. Change to method lookup rules to look

into primary class's named categories before looking 
into their protocols. This is because categories are
part of the public interface and , just as primary class,
preference should be given to them before class 
(and category) protocols.  // rdar://18013929

llvm-svn: 216610

1 files changed, 15 insertions, 12 deletions

diff --git a/clang/lib/AST/DeclObjC.cpp b/clang/lib/AST/DeclObjC.cpp
index e753feb3d9e..cc6560787ca 100644
--- a/clang/lib/AST/DeclObjC.cpp
+++ b/clang/lib/AST/DeclObjC.cpp
@@ -558,36 +558,39 @@ ObjCMethodDecl *ObjCInterfaceDecl::lookupMethod(Selector Sel,
     LoadExternalDefinition();
 
   while (ClassDecl) {
+    // 1. Look through primary class.
     if ((MethodDecl = ClassDecl->getMethod(Sel, isInstance)))
       return MethodDecl;
-
-    // Didn't find one yet - look through protocols.
-    for (const auto *I : ClassDecl->protocols())
-      if ((MethodDecl = I->lookupMethod(Sel, isInstance)))
-        return MethodDecl;
     
-    // Didn't find one yet - now look through categories.
-    for (const auto *Cat : ClassDecl->visible_categories()) {
+    // 2. Didn't find one yet - now look through categories.
+    for (const auto *Cat : ClassDecl->visible_categories())
       if ((MethodDecl = Cat->getMethod(Sel, isInstance)))
         if (C != Cat || !MethodDecl->isImplicit())
           return MethodDecl;
 
-      if (!shallowCategoryLookup) {
+    // 3. Didn't find one yet - look through primary class's protocols.
+    for (const auto *I : ClassDecl->protocols())
+      if ((MethodDecl = I->lookupMethod(Sel, isInstance)))
+        return MethodDecl;
+    
+    // 4. Didn't find one yet - now look through categories' protocols
+    if (!shallowCategoryLookup)
+      for (const auto *Cat : ClassDecl->visible_categories()) {
         // Didn't find one yet - look through protocols.
         const ObjCList<ObjCProtocolDecl> &Protocols =
-        Cat->getReferencedProtocols();
+          Cat->getReferencedProtocols();
         for (ObjCList<ObjCProtocolDecl>::iterator I = Protocols.begin(),
              E = Protocols.end(); I != E; ++I)
           if ((MethodDecl = (*I)->lookupMethod(Sel, isInstance)))
             if (C != Cat || !MethodDecl->isImplicit())
               return MethodDecl;
       }
-    }
-
+    
+    
     if (!followSuper)
       return nullptr;
 
-    // Get the super class (if any).
+    // 5. Get to the super class (if any).
     ClassDecl = ClassDecl->getSuperClass();
   }
   return nullptr;