Index: cp/decl.c
===================================================================
--- cp/decl.c	(revision 265510)
+++ cp/decl.c	(working copy)
@@ -4798,9 +4798,10 @@ check_tag_decl (cp_decl_specifier_seq *declspecs,
     declared_type = declspecs->type;
   else if (declspecs->type == error_mark_node)
     error_p = true;
-  if (declared_type == NULL_TREE && ! saw_friend && !error_p)
+  if ((!declared_type || TREE_CODE (declared_type) == DECLTYPE_TYPE)
+      && ! saw_friend && !error_p)
     permerror (input_location, "declaration does not declare anything");
-  else if (declared_type != NULL_TREE && type_uses_auto (declared_type))
+  else if (declared_type && type_uses_auto (declared_type))
     {
       error_at (declspecs->locations[ds_type_spec],
 		"%<auto%> can only be specified for variables "
@@ -4884,7 +4885,8 @@ check_tag_decl (cp_decl_specifier_seq *declspecs,
 		  "%<constexpr%> cannot be used for type declarations");
     }
 
-  if (declspecs->attributes && warn_attributes && declared_type)
+  if (declspecs->attributes && warn_attributes && declared_type
+      && TREE_CODE (declared_type) != DECLTYPE_TYPE)
     {
       location_t loc;
       if (!CLASS_TYPE_P (declared_type)
Index: testsuite/g++.dg/cpp0x/decltype-33838.C
===================================================================
--- testsuite/g++.dg/cpp0x/decltype-33838.C	(revision 265510)
+++ testsuite/g++.dg/cpp0x/decltype-33838.C	(working copy)
@@ -2,5 +2,5 @@
 // PR c++/33838
 template<typename T> struct A
 {
-  __decltype (T* foo()); // { dg-error "expected|no arguments|accept" }
+  __decltype (T* foo()); // { dg-error "expected|no arguments|declaration" }
 };
Index: testsuite/g++.dg/cpp0x/decltype68.C
===================================================================
--- testsuite/g++.dg/cpp0x/decltype68.C	(nonexistent)
+++ testsuite/g++.dg/cpp0x/decltype68.C	(working copy)
@@ -0,0 +1,7 @@
+// PR c++/84644
+// { dg-do compile { target c++11 } }
+
+template<int a>
+struct b {
+  decltype(a) __attribute__((break));  // { dg-error "declaration does not declare anything" }
+};