diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 6f0b96b5b4c8..cf7a062bd615 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,13 @@
+2006-07-18  Lee Millward  <lee.millward@gmail.com>
+
+	PR c++/28258
+	* method.c (locate_copy): Check for non_reference
+	returning error_mark_node.
+
+        PR c++/28260
+	* decl.c (duplicate_decls): Return error_mark_node
+	on ambiguous declaration.
+	
 2006-07-18  Steve Ellcey  <sje@cup.hp.com>
 
 	PR c++/27495
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index dd0e7e3e892e..6165a2fb4fe8 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -1371,6 +1371,7 @@ duplicate_decls (tree newdecl, tree olddecl, bool newdecl_is_friend)
 	    {
 	      error ("new declaration %q#D", newdecl);
 	      error ("ambiguates old declaration %q+#D", olddecl);
+              return error_mark_node;
 	    }
 	  else
 	    return NULL_TREE;
diff --git a/gcc/cp/method.c b/gcc/cp/method.c
index 9029e85a653a..312e3a9c04a1 100644
--- a/gcc/cp/method.c
+++ b/gcc/cp/method.c
@@ -946,6 +946,10 @@ locate_copy (tree type, void *client_)
       if (!parms)
 	continue;
       src_type = non_reference (TREE_VALUE (parms));
+
+      if (src_type == error_mark_node)
+        return NULL_TREE;
+
       if (!same_type_ignoring_top_level_qualifiers_p (src_type, type))
 	continue;
       if (!sufficient_parms_p (TREE_CHAIN (parms)))
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 4df2b2f72011..2025aadbacc2 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2006-07-18  Lee Millward  <lee.millward@gmail.com>
+
+	PR c++/28258
+	* g++/dg/other/error13.C: New test.
+
+	PR c++/28260
+	* g++.dg/template/friend44.C: New test.
+	
 2006-07-18  Steve Ellcey  <sje@cup.hp.com>
 
 	PR c++/27495
diff --git a/gcc/testsuite/g++.dg/other/error13.C b/gcc/testsuite/g++.dg/other/error13.C
new file mode 100644
index 000000000000..037e28866e10
--- /dev/null
+++ b/gcc/testsuite/g++.dg/other/error13.C
@@ -0,0 +1,10 @@
+//PR c++/28258
+
+struct A 
+{            // { dg-error "" }
+  A(void x); // { dg-error "invalid use|incomplete type|candidates" }
+};
+
+struct B : A {}; // { dg-error "no matching function for call" }
+ 
+B b; // { dg-error "synthesized method" }
diff --git a/gcc/testsuite/g++.dg/template/friend44.C b/gcc/testsuite/g++.dg/template/friend44.C
new file mode 100644
index 000000000000..a0f63c866ae4
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/friend44.C
@@ -0,0 +1,8 @@
+//PR c++/28260
+
+template<int> struct A
+{
+  friend int foo(); // { dg-error "new declaration" }
+};
+
+void foo() { A<0> a; } // { dg-error "ambiguates old declaration" }