diff --git a/ChangeLog b/ChangeLog
index f368f9bbad..29dda9ebbe 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+Tue Dec 23 14:13:51 2003  akira yamada  <akira@ruby-lang.org>
+
+	* lib/uri/generic.rb (URI::Generic::check_userinfo,
+	  URI::Generic::check_user, URI::Generic::check_password): tests
+	  conflicts/depends with other components closely.
+
+	* test/uri/test_generic.rb (TestGeneric::test_set_component):
+	  added tets.
+	
 Tue Dec 23 11:08:34 2003  NAKAMURA, Hiroshi  <nahi@ruby-lang.org>
 
 	* test/xsd/test_noencoding.rb: rescue Errno::EINVAL and do not test.
diff --git a/lib/uri/generic.rb b/lib/uri/generic.rb
index a968101468..c1d0d63cae 100644
--- a/lib/uri/generic.rb
+++ b/lib/uri/generic.rb
@@ -265,23 +265,22 @@ Object
     # methods for userinfo
     #
     def check_userinfo(user, password = nil)
-      if (user || password) &&
-	  (@registry || @opaque)
-	raise InvalidURIError, 
-	  "can not set userinfo with registry or opaque"
-      end
-
       if !password
 	user, password = split_userinfo(user)
       end
       check_user(user)
-      check_password(password)
+      check_password(password, user)
 
       return true
     end
     private :check_userinfo
 
     def check_user(v)
+      if @registry || @opaque
+	raise InvalidURIError, 
+	  "can not set user with registry or opaque"
+      end
+
       return v unless v
 
       if USERINFO !~ v
@@ -293,10 +292,14 @@ Object
     end
     private :check_user
 
-    def check_password(v)
+    def check_password(v, user = @user)
+      if @registry || @opaque
+	raise InvalidURIError, 
+	  "can not set password with registry or opaque"
+      end
       return v unless v
 
-      if !@password
+      if !user
 	raise InvalidURIError,
 	  "password component depends user component"
       end
diff --git a/test/uri/test_generic.rb b/test/uri/test_generic.rb
index 34876ebaed..25d01f0606 100644
--- a/test/uri/test_generic.rb
+++ b/test/uri/test_generic.rb
@@ -619,6 +619,22 @@ class TestGeneric < Test::Unit::TestCase
     assert_equal('http://foo:bar@zab:8080/?a=1', uri.to_s)
     assert_equal('b123', uri.fragment = 'b123')
     assert_equal('http://foo:bar@zab:8080/?a=1#b123', uri.to_s)
+
+    uri = URI.parse('http://example.com')
+    assert_raises(URI::InvalidURIError) { uri.password = 'bar' }
+    uri.userinfo = 'foo:bar'
+    assert_equal('http://foo:bar@example.com', uri.to_s)
+    assert_raises(URI::InvalidURIError) { uri.registry = 'bar' }
+    assert_raises(URI::InvalidURIError) { uri.opaque = 'bar' }
+
+    uri = URI.parse('mailto:foo@example.com')
+    assert_raises(URI::InvalidURIError) { uri.user = 'bar' }
+    assert_raises(URI::InvalidURIError) { uri.password = 'bar' }
+    assert_raises(URI::InvalidURIError) { uri.userinfo = ['bar', 'baz'] }
+    assert_raises(URI::InvalidURIError) { uri.host = 'bar' }
+    assert_raises(URI::InvalidURIError) { uri.port = 'bar' }
+    assert_raises(URI::InvalidURIError) { uri.path = 'bar' }
+    assert_raises(URI::InvalidURIError) { uri.query = 'bar' }
   end
 end