diff --git a/ChangeLog b/ChangeLog
index f8d688fa98..10349a548e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sun Aug 29 13:22:43 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* vm.c (rb_thread_method_id_and_class): curried proc has no
+	  method.  [ruby-core:31871]
+
 Fri Sep 24 23:44:59 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* string.c (sym_call), vm.c (invoke_block_from_c),
diff --git a/test/ruby/test_proc.rb b/test/ruby/test_proc.rb
index 4a1eee3926..efd5a269fd 100644
--- a/test/ruby/test_proc.rb
+++ b/test/ruby/test_proc.rb
@@ -793,6 +793,14 @@ class TestProc < Test::Unit::TestCase
     end
   end
 
+  def test_curry_with_trace
+    bug3751 = '[ruby-core:31871]'
+    set_trace_func(proc {})
+    test_curry
+  ensure
+    set_trace_func(nil)
+  end
+
   def test_block_propagation
     bug3792 = '[ruby-core:32075]'
     c = Class.new do
diff --git a/version.h b/version.h
index 5273dc876d..d492f33902 100644
--- a/version.h
+++ b/version.h
@@ -1,5 +1,5 @@
 #define RUBY_VERSION "1.9.2"
-#define RUBY_PATCHLEVEL 54
+#define RUBY_PATCHLEVEL 55
 #define RUBY_VERSION_MAJOR 1
 #define RUBY_VERSION_MINOR 9
 #define RUBY_VERSION_TEENY 1
diff --git a/vm.c b/vm.c
index 8938df9d51..e235314b99 100644
--- a/vm.c
+++ b/vm.c
@@ -1396,7 +1396,7 @@ rb_thread_method_id_and_class(rb_thread_t *th,
 {
     rb_control_frame_t *cfp = th->cfp;
     rb_iseq_t *iseq = cfp->iseq;
-    if (!iseq) {
+    if (!iseq && cfp->me) {
 	if (idp) *idp = cfp->me->def->original_id;
 	if (klassp) *klassp = cfp->me->klass;
 	return 1;