diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 4f27d9f7acdf..7c7b920119e4 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -3094,7 +3094,7 @@ def err_arc_mismatched_cast : Error<
 def err_arc_nolifetime_behavior : Error<
   "explicit ownership qualifier on cast result has no effect">;
 def err_arc_objc_object_in_struct : Error<
-  "ARC forbids Objective-C objects in structs or unions">;
+  "ARC forbids %select{Objective-C objects|blocks}0 in structs or unions">;
 def err_arc_objc_property_default_assign_on_object : Error<
   "ARC forbids synthesizing a property of an Objective-C object "
   "with unspecified ownership or storage attribute">;
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 09ada7e55dc4..bd2e639eab0a 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -9206,7 +9206,8 @@ void Sema::ActOnFields(Scope* S,
                                 "this system field has retaining ownership"));
             }
           } else {
-            Diag(FD->getLocation(), diag::err_arc_objc_object_in_struct);
+            Diag(FD->getLocation(), diag::err_arc_objc_object_in_struct) 
+              << T->isBlockPointerType();
           }
           ARCErrReported = true;
         }
diff --git a/clang/test/SemaObjC/arc-decls.m b/clang/test/SemaObjC/arc-decls.m
index 1084db86268f..4b7eb8fb54d0 100644
--- a/clang/test/SemaObjC/arc-decls.m
+++ b/clang/test/SemaObjC/arc-decls.m
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -fobjc-arc -verify %s
+// RUN: %clang_cc1 -fsyntax-only -fblocks -fobjc-arc -verify %s
 
 // rdar://8843524
 
@@ -21,6 +21,11 @@ union u {
 };
 @end
 
+// rdar://10260525
+struct r10260525 {
+  id (^block) (); // expected-error {{ARC forbids blocks in structs or unions}}
+};
+
 struct S { 
     id __attribute__((objc_ownership(none))) i;
     void * vp;