More semantics checks of properties. Property implementation can implicitly use
ivar of same name. 
Better diagnostics to bring home this point.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@50065 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaDeclObjC.cpp b/lib/Sema/SemaDeclObjC.cpp
index 45d8777..234bead 100644
--- a/lib/Sema/SemaDeclObjC.cpp
+++ b/lib/Sema/SemaDeclObjC.cpp
@@ -998,14 +998,13 @@
   // Check that we have a valid, previously declared ivar for @synthesize
   if (Synthesize) {
     // @synthesize
-    if (!PropertyIvar) {
-      Diag(PropertyLoc, diag::error_property_ivar_decl);
-      return 0;
-    }
+    if (!PropertyIvar)
+      PropertyIvar = PropertyId;
     // Check that this is a previously declared 'ivar' in 'IDecl' interface
     ObjCIvarDecl *Ivar = IDecl->FindIvarDeclaration(PropertyIvar);
     if (!Ivar) {
-      Diag(PropertyLoc, diag::error_missing_property_ivar_decl);
+      Diag(PropertyLoc, diag::error_missing_property_ivar_decl, 
+           PropertyId->getName());
       return 0;
     }
     // Check that type of property and its ivar match.