diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index f0c0193a388..b9e83d4348c 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2011-08-23  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/46862
+	* class.c (finish_struct_1): If TYPE_TRANSPARENT_AGGR is set on a type
+	which doesn't have any fields, clear it and diagnose.
+
 2011-08-18  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
 	    Marc Glisse  <marc.glisse@normalesup.org>
 
diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index fd0f011d0ae..6ebe7588cb8 100644
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -1,6 +1,6 @@
 /* Functions related to building classes and their related objects.
    Copyright (C) 1987, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
-   1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010
+   1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010, 2011
    Free Software Foundation, Inc.
    Contributed by Michael Tiemann (tiemann@cygnus.com)
 
@@ -5794,6 +5794,12 @@ finish_struct_1 (tree t)
 
   /* Finish debugging output for this type.  */
   rest_of_type_compilation (t, ! LOCAL_CLASS_P (t));
+
+  if (TYPE_TRANSPARENT_AGGR (t) && first_field (t) == NULL_TREE)
+    {
+      error ("type transparent class %qT does not have any fields", t);
+      TYPE_TRANSPARENT_AGGR (t) = 0;
+    }
 }
 
 /* When T was built up, the member declarations were added in reverse
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index fa80622a4e2..6d413f35762 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2011-08-23  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/46862
+	* g++.dg/dfp/nofields.C: New test.
+
 2011-08-23  Tobias Burnus  <burnus@net-b.de>
 
 	PR fortran/31600
diff --git a/gcc/testsuite/g++.dg/dfp/nofields.C b/gcc/testsuite/g++.dg/dfp/nofields.C
new file mode 100644
index 00000000000..7234672d4e0
--- /dev/null
+++ b/gcc/testsuite/g++.dg/dfp/nofields.C
@@ -0,0 +1,19 @@
+// PR c++/46862
+// { dg-do compile }
+
+namespace std
+{
+  namespace decimal
+  {
+    class decimal32 { };	// { dg-error "does not have any fields" }
+    class decimal64 { };	// { dg-error "does not have any fields" }
+    class decimal128 { };	// { dg-error "does not have any fields" }
+  }
+}
+
+void
+foo (std::decimal::decimal32 x,
+     std::decimal::decimal64 y,
+     std::decimal::decimal128 z)
+{
+}