diff --git a/ChangeLog b/ChangeLog
index ac9ed5c994..0648bd18a8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Sun Nov 16 13:26:07 2003  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* eval.c (eval): prepend error position in evaluating string to
+	  "mesg" attribute string only when it's available and is a
+	  string.
+
 Sun Nov 16 12:16:10 2003  Minero Aoki  <aamine@loveruby.net>
 
 	* lib/net/protocol.rb: logging response body. [experimental]
diff --git a/eval.c b/eval.c
index 4d3fd66b7f..4a582ded66 100644
--- a/eval.c
+++ b/eval.c
@@ -5582,10 +5582,12 @@ eval(self, src, scope, file, line)
 	    if (strcmp(file, "(eval)") == 0) {
 		VALUE mesg, errat;
 
-		errat = get_backtrace(ruby_errinfo);
-		mesg  = rb_obj_as_string(ruby_errinfo);
-		rb_str_update(mesg, 0, 0, RARRAY(errat)->ptr[0]);
-		RARRAY(errat)->ptr[0] = RARRAY(backtrace(-2))->ptr[0];
+		mesg  = rb_attr_get(ruby_errinfo, rb_intern("mesg"));
+		if (!NIL_P(mesg) && TYPE(mesg) == T_STRING) {
+		    errat = get_backtrace(ruby_errinfo);
+		    rb_str_update(mesg, 0, 0, RARRAY(errat)->ptr[0]);
+		    RARRAY(errat)->ptr[0] = RARRAY(backtrace(-2))->ptr[0];
+		}
 	    }
 	    rb_exc_raise(ruby_errinfo);
 	}