diff --git a/ChangeLog b/ChangeLog
index 7fb0b71967..c25329d427 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Fri Jan 23 14:19:28 1998  Yukihiro Matsumoto  <matz@netlab.co.jp>
+
+	* object.c (mod_to_s): need to duplicate classpath.
+
+	* error.c (exc_inspect): need to duplicate classpath.
+
 Thu Jan 22 00:37:47 1998  Yukihiro Matsumoto  <matz@netlab.co.jp>
 
 	* ruby.h (STR2CSTR): new macro to retrieve char*.
diff --git a/error.c b/error.c
index bdc38ecb55..4c8aea5964 100644
--- a/error.c
+++ b/error.c
@@ -254,7 +254,7 @@ exc_inspect(exc)
 
     klass = CLASS_OF(exc);
     if (RSTRING(exc)->len == 0) {
-	return rb_class_path(klass);
+	return str_dup(rb_class_path(klass));
     }
 
     str = str_new2("#<");
diff --git a/object.c b/object.c
index be551bd82a..b515b45202 100644
--- a/object.c
+++ b/object.c
@@ -386,7 +386,7 @@ static VALUE
 mod_to_s(class)
     VALUE class;
 {
-    return rb_class_path(class);
+    return str_dup(rb_class_path(class));
 }
 
 static VALUE
diff --git a/variable.c b/variable.c
index 7511264330..fa3a79516f 100644
--- a/variable.c
+++ b/variable.c
@@ -130,12 +130,6 @@ classname(klass)
 	klass = (VALUE)RCLASS(klass)->super;
     }
     path = rb_iv_get(klass, "__classpath__");
-    if (NIL_P(path)) {
-	path = rb_iv_get(klass, "__classid__");
-	if (!NIL_P(path)) {
-	    path = str_new2(rb_id2name(FIX2INT(path)));
-	}
-    }
     if (NIL_P(path)) {
 	path = find_class_path(klass);
 	if (NIL_P(path)) {
@@ -153,7 +147,7 @@ mod_name(mod)
 {
     VALUE path = classname(mod);
 
-    if (path) return path;
+    if (path) return str_dup(path);
     return str_new(0,0);
 }
 
@@ -209,12 +203,7 @@ rb_name_class(klass, id)
 {
     extern VALUE cString;
 
-    if (cString) {
-	rb_iv_set(klass, "__classpath__", str_new2(rb_id2name(id)));
-    }
-    else {
-	rb_iv_set(klass, "__classid__", INT2FIX(id));
-    }
+    rb_iv_set(klass, "__classpath__", str_new2(rb_id2name(id)));
 }
 
 static st_table *autoload_tbl = 0;