diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 65edb9c47a51..6dd6137ee5d1 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2011-02-03  Dodji Seketeli  <dodji@redhat.com>
+
+	PR c++/47398
+	* tree.c (cp_tree_equal)<TEMPLATE_PARM_INDEX>: Take the number of
+	template parameters in account.
+
 2011-02-03  Nathan Froyd  <froydnj@codesourcery.com>
 
 	PR c++/46890
diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index 1a1f150e1cec..d62d2427f1e4 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -2176,6 +2176,9 @@ cp_tree_equal (tree t1, tree t2)
 				BASELINK_FUNCTIONS (t2)));
 
     case TEMPLATE_PARM_INDEX:
+      if (TEMPLATE_PARM_NUM_SIBLINGS (t1)
+	  != TEMPLATE_PARM_NUM_SIBLINGS (t2))
+	return false;
       return (TEMPLATE_PARM_IDX (t1) == TEMPLATE_PARM_IDX (t2)
 	      && TEMPLATE_PARM_LEVEL (t1) == TEMPLATE_PARM_LEVEL (t2)
 	      && (TEMPLATE_PARM_PARAMETER_PACK (t1)
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index e32c521dabe3..d387efe79803 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2011-02-03  Dodji Seketeli  <dodji@redhat.com>
+
+	PR c++/47398
+	* g++.dg/template/typedef37.C: New test.
+	* g++.dg/template/param1.C: Adjust expected error message.
+
 2011-02-03  Jakub Jelinek  <jakub@redhat.com>
 
 	PR middle-end/31490
diff --git a/gcc/testsuite/g++.dg/template/param1.C b/gcc/testsuite/g++.dg/template/param1.C
index ad7fc8cde0e1..a8c3791254fd 100644
--- a/gcc/testsuite/g++.dg/template/param1.C
+++ b/gcc/testsuite/g++.dg/template/param1.C
@@ -2,11 +2,11 @@
 // Origin: Volker Reichelt  <reichelt@igpm.rwth-aachen.de>
 // { dg-do compile }
 
-template<int> struct A
+template<int> struct A // { dg-error "declaration" }
 {
   A();
 };
 
-template<int N, char> A<N>::A() {}  // { dg-error "got 2|but 1 required" }
+template<int N, char> A<N>::A() {}  // { dg-error "invalid use of incomplete type" }
 
 A<0> a;
diff --git a/gcc/testsuite/g++.dg/template/typedef37.C b/gcc/testsuite/g++.dg/template/typedef37.C
new file mode 100644
index 000000000000..eefa38316ca6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/typedef37.C
@@ -0,0 +1,58 @@
+// Origin: PR c++/47398
+// { dg-do compile }
+
+template<int>
+struct A
+{
+  typedef int INT;
+};
+
+template<int I>
+struct transform
+{
+  static int bar();
+};
+
+template<class T, int a, class U, int b>
+struct B
+{
+  typedef typename A<a>::INT TINT;
+  void baz();
+};
+
+template<class T, int a, class U>
+struct B<T, a, U, 1>
+{
+  typedef typename A<a>::INT TINT;
+  void foo();
+};
+
+template<class T, int a, class U, int b>
+void
+B<T, a, U, b>::baz()
+{
+  int c = transform<sizeof(TINT)>::bar();//#0
+}
+
+template<class T, int a, class U>
+void
+B<T, a, U, 1>::foo()
+{
+  int c = transform<sizeof(TINT)>::bar();//#1
+}
+
+int
+main()
+{
+  B<int, 2, char, 1> i;
+  i.foo();
+  // While instantiating
+  //
+  //   template<class T, int a, class U> void B<T, a, U, 1>::foo()
+  //
+  // lookup_template_class resolves transform<sizeof(TINT)> in #1 to
+  // the wrong one; it picks up the one in #0 instead. This is because
+  // to compare the two A<a> comp_template_args uses cp_tree_equal
+  // that fails to consider the number of siblings of parm 'a'.
+return 0;
+}