diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index be42b37cbfd..9760ccfca04 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2008-09-09  Jason Merrill  <jason@redhat.com>
+
+	PR c++/37439
+	* pt.c (tsubst_copy) [PARM_DECL]: Don't abort if the parm has
+	DECL_CONTEXT set.
+
 2008-09-09  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/37389
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 4aa7b1ad146..cdaae59914e 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -9809,7 +9809,7 @@ tsubst_copy (tree t, tree args, tsubst_flags_t complain, tree in_decl)
 	     Replace it with an arbitrary expression with the same type
 	     (*(T*)0).  This should only occur in an unevaluated context
 	     (i.e. decltype).  */
-	  gcc_assert (skip_evaluation && DECL_CONTEXT (t) == NULL_TREE);
+	  gcc_assert (skip_evaluation);
 	  r = non_reference (TREE_TYPE (t));
 	  r = tsubst (r, args, complain, in_decl);
 	  r = build_pointer_type (r);
diff --git a/gcc/testsuite/g++.dg/cpp0x/auto6.C b/gcc/testsuite/g++.dg/cpp0x/auto6.C
index a574f54758f..713583a1a48 100644
--- a/gcc/testsuite/g++.dg/cpp0x/auto6.C
+++ b/gcc/testsuite/g++.dg/cpp0x/auto6.C
@@ -6,7 +6,10 @@ auto f() -> int
 }
 
 template<class T, class U>
-auto add(T t, U u) -> decltype (t+u);
+auto add(T t, U u) -> decltype (t+u)
+{
+  return t+u;
+}
 
 template<class T, class U>
 decltype(T()+U()) add2(T t, U u);