Index: lib/Sema/SemaOverload.cpp
===================================================================
--- lib/Sema/SemaOverload.cpp
+++ lib/Sema/SemaOverload.cpp
@@ -11804,7 +11804,8 @@
   // various built-in candidates, but as DR507 points out, this can lead to
   // problems. So we do it this way, which pretty much follows what GCC does.
   // Note that we go the traditional code path for compound assignment forms.
-  if (Opc == BO_Assign && !Args[0]->getType()->isOverloadableType())
+  if (!LangOpts.CPlusPlus ||
+      (Opc == BO_Assign && !Args[0]->getType()->isOverloadableType()))
     return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]);
 
   // If this is the .* operator, which is not overloadable, just
Index: test/Sema/PR28181.c
===================================================================
--- /dev/null
+++ test/Sema/PR28181.c
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+struct spinlock_t {
+  int lock;
+} audit_skb_queue;
+
+void fn1() {
+  audit_skb_queue = (lock); // expected-error {{use of undeclared identifier 'lock'; did you mean 'long'?}}
+}                           // expected-error@-1 {{assigning to 'struct spinlock_t' from incompatible type '<overloaded function type>'}}
+
+void fn2() {
+  audit_skb_queue + (lock); // expected-error {{use of undeclared identifier 'lock'; did you mean 'long'?}}
+}                           // expected-error@-1 {{reference to overloaded function could not be resolved; did you mean to call it?}}