diff --git a/clang/test/CXX/drs/dr13xx.cpp b/clang/test/CXX/drs/dr13xx.cpp
--- a/clang/test/CXX/drs/dr13xx.cpp
+++ b/clang/test/CXX/drs/dr13xx.cpp
@@ -13,6 +13,16 @@
   };
 }
 
+#if __cplusplus >= 201103L
+namespace dr1305 { // dr1305: yes
+struct Incomplete; // expected-note {{forward declaration of 'dr1305::Incomplete'}}
+struct Complete {};
+
+int incomplete = alignof(Incomplete(&)[]); // expected-error {{invalid application of 'alignof' to an incomplete type 'dr1305::Incomplete'}}
+int complete = alignof(Complete(&)[]);
+}
+#endif
+
 namespace dr1310 { // dr1310: 5
   struct S {} * sp = new S::S; // expected-error {{qualified reference to 'S' is a constructor name}}
   void f() {
diff --git a/clang/www/cxx_dr_status.html b/clang/www/cxx_dr_status.html
--- a/clang/www/cxx_dr_status.html
+++ b/clang/www/cxx_dr_status.html
@@ -7644,7 +7644,7 @@
     <td><a href="https://wg21.link/cwg1305">1305</a></td>
     <td>CD3</td>
     <td><TT>alignof</TT> applied to array of unknown size</td>
-    <td class="none" align="center">Unknown</td>
+    <td class="full" align="center">Yes</td>
   </tr>
   <tr id="1306">
     <td><a href="https://wg21.link/cwg1306">1306</a></td>