diff --git a/ChangeLog b/ChangeLog
index 592f7bd9c7..a96826c514 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Jul  4 04:58:30 2007  Koichi Sasada  <ko1@atdot.net>
+
+	* insnhelper.ci (caller_setup_args): fix to show correct class
+	  on an error message (ex: m(&1)). [ruby-dev:31101]
+
 Wed Jul  4 04:30:32 2007  Koichi Sasada  <ko1@atdot.net>
 
 	* compile.c (compile_array, iseq_compile_each): fix about array
diff --git a/insnhelper.ci b/insnhelper.ci
index 92e88e9632..73ea6ee09a 100644
--- a/insnhelper.ci
+++ b/insnhelper.ci
@@ -196,12 +196,13 @@ caller_setup_args(rb_thread_t *th, rb_control_frame_t *cfp, VALUE flag,
 
 	    if (proc != Qnil) {
 		if (!rb_obj_is_proc(proc)) {
-		    proc = rb_check_convert_type(proc, T_DATA, "Proc", "to_proc");
-		    if (!rb_obj_is_proc(proc)) {
+		    VALUE b = rb_check_convert_type(proc, T_DATA, "Proc", "to_proc");
+		    if (NIL_P(b)) {
 			rb_raise(rb_eTypeError,
 				 "wrong argument type %s (expected Proc)",
 				 rb_obj_classname(proc));
 		    }
+		    proc = b;
 		}
 		GetProcPtr(proc, po);
 		blockptr = &po->block;