Implement simplify_type traits for redecl_iterator.

Based on Chandler Carruth's feedback on r155869.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@155929 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/AST/DeclBase.h b/include/clang/AST/DeclBase.h
index 555ce3c..6382bf3 100644
--- a/include/clang/AST/DeclBase.h
+++ b/include/clang/AST/DeclBase.h
@@ -1632,6 +1632,23 @@
   }
 };
 
+// simplify_type - Allow clients to treat redecl_iterators just like Decl
+// pointers when using casting operators.
+template<> struct simplify_type< ::clang::Decl::redecl_iterator> {
+  typedef ::clang::Decl *SimpleType;
+  static SimpleType getSimplifiedValue(const ::clang::Decl::redecl_iterator
+      &Val) {
+    return Val;
+  }
+};
+template<> struct simplify_type<const ::clang::Decl::redecl_iterator> {
+  typedef ::clang::Decl *SimpleType;
+  static SimpleType getSimplifiedValue(const ::clang::Decl::redecl_iterator
+      &Val) {
+    return Val;
+  }
+};
+
 } // end namespace llvm
 
 #endif
diff --git a/lib/Sema/SemaLookup.cpp b/lib/Sema/SemaLookup.cpp
index 3a6e290..78a9905 100644
--- a/lib/Sema/SemaLookup.cpp
+++ b/lib/Sema/SemaLookup.cpp
@@ -1069,7 +1069,7 @@
   
   for (Decl::redecl_iterator RD = D->redecls_begin(), RDEnd = D->redecls_end();
        RD != RDEnd; ++RD) {
-    if (NamedDecl *ND = dyn_cast<NamedDecl>(&*RD)) {
+    if (NamedDecl *ND = dyn_cast<NamedDecl>(RD)) {
       if (LookupResult::isVisible(ND))
         return ND;
     }