diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index ffb22aa776f..51d26cecc4b 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -31830,7 +31830,7 @@ cp_parser_base_specifier (cp_parser* parser)
   tree std_attrs = cp_parser_std_attribute_spec_seq (parser);
   tree annotations = NULL_TREE;
 
-  if (std_attrs != NULL_TREE)
+  if (std_attrs != NULL_TREE && std_attrs != error_mark_node)
     {
       tree *pannotations = &annotations;
       for (tree attr = std_attrs; attr; attr = TREE_CHAIN (attr))
diff --git a/gcc/testsuite/g++.dg/cpp0x/alignas24.C b/gcc/testsuite/g++.dg/cpp0x/alignas24.C
new file mode 100644
index 00000000000..2966a9c2aa3
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/alignas24.C
@@ -0,0 +1,5 @@
+// PR c++/124307
+// { dg-do compile { target c++11 } }
+// { dg-options "" }
+
+class : alignas // { dg-error "" }