diff --git a/ChangeLog b/ChangeLog
index 9401f8f..9053da1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+Sun Dec  7 17:09:17 2008  Minero Aoki  <aamine@loveruby.net>
+
+	* net/loveruby/cflat/ast/ToplevelScope.java: use SemanticException
+	  instead of SemanticError for duplicated declarations/definitions.
+
+Sun Dec  7 17:08:26 2008  Minero Aoki  <aamine@loveruby.net>
+
+	* test: test declaration override (error path).
+
 Sun Dec  7 16:55:56 2008  Minero Aoki  <aamine@loveruby.net>
 
 	* test: test declaration override.
diff --git a/net/loveruby/cflat/ast/ToplevelScope.java b/net/loveruby/cflat/ast/ToplevelScope.java
index 315120f..2c3e970 100644
--- a/net/loveruby/cflat/ast/ToplevelScope.java
+++ b/net/loveruby/cflat/ast/ToplevelScope.java
@@ -28,21 +28,25 @@ public class ToplevelScope extends Scope {
 
     /** Declare variable or function globally. */
     // #@@range/declareEntity{
-    public void declareEntity(Entity ent) {
-        if (entities.containsKey(ent.name())) {
-            throw new Error("duplicated declaration: " + ent.name());
+    public void declareEntity(Entity entity) throws SemanticException {
+        Entity e = entities.get(entity.name());
+        if (e != null) {
+            throw new SemanticException("duplicated declaration: " +
+                    entity.name() + ": " +
+                    e.location() + " and " + entity.location());
         }
-        entities.put(ent.name(), ent);
+        entities.put(entity.name(), entity);
     }
     // #@@}
 
     /** Define variable or function globally. */
     // #@@range/defineEntity{
-    public void defineEntity(Entity entity) {
-        Entity ent = entities.get(entity.name());
-        if (ent != null && ent.isDefined()) {
-            throw new Error("duplicated definition: " + entity.name() + ": " +
-                            ent.location() + " and " + entity.location());
+    public void defineEntity(Entity entity) throws SemanticException {
+        Entity e = entities.get(entity.name());
+        if (e != null && e.isDefined()) {
+            throw new SemanticException("duplicated definition: " +
+                    entity.name() + ": " +
+                    e.location() + " and " + entity.location());
         }
         entities.put(entity.name(), entity);
     }