commit 3b93aba17af31a772141a871c3299250dbbda714
Author: Jason Merrill <jason@redhat.com>
Date:   Wed May 25 01:21:49 2011 -0400

    	PR c++/45080
    	* pt.c (instantiate_class_template_1): Call maybe_add_lambda_conv_op.
    	* semantics.c (lambda_function): Check COMPLETE_OR_OPEN_TYPE_P.

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index fc84314..bb4515b 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -8566,6 +8566,9 @@ instantiate_class_template_1 (tree type)
 	}
     }
 
+  if (CLASSTYPE_LAMBDA_EXPR (type))
+    maybe_add_lambda_conv_op (type);
+
   /* Set the file and line number information to whatever is given for
      the class itself.  This puts error messages involving generated
      implicit functions at a predictable point, and the same point
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 50f25f0..55ad117 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -8145,7 +8145,8 @@ lambda_function (tree lambda)
     type = lambda;
   gcc_assert (LAMBDA_TYPE_P (type));
   /* Don't let debug_tree cause instantiation.  */
-  if (CLASSTYPE_TEMPLATE_INSTANTIATION (type) && !COMPLETE_TYPE_P (type))
+  if (CLASSTYPE_TEMPLATE_INSTANTIATION (type)
+      && !COMPLETE_OR_OPEN_TYPE_P (type))
     return NULL_TREE;
   lambda = lookup_member (type, ansi_opname (CALL_EXPR),
 			  /*protect=*/0, /*want_type=*/false);
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-conv5.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-conv5.C
new file mode 100644
index 0000000..53d8e99
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-conv5.C
@@ -0,0 +1,15 @@
+// PR c++/45080
+// { dg-options -std=c++0x }
+
+typedef void(*pfn)();
+
+template<typename=int>
+void f()
+{
+  pfn fn = []{};
+}
+
+void test()
+{
+  f();
+}