Index: wp-admin/includes/post.php
===================================================================
--- wp-admin/includes/post.php	(revision 14330)
+++ wp-admin/includes/post.php	(working copy)
@@ -1067,7 +1067,9 @@
  * @return string intended to be used for the inplace editor of the permalink post slug on in the post (and page?) editor.
  */
 function get_sample_permalink_html( $id, $new_title = null, $new_slug = null ) {
+	global $wpdb;
 	$post = &get_post($id);
+	$orig_permalink = sanitize_title($post->post_title);
 	list($permalink, $post_name) = get_sample_permalink($post->ID, $new_title, $new_slug);
 
 	if ( 'publish' == $post->post_status ) {
@@ -1110,6 +1112,18 @@
 		}
 	}
 
+	if ( $orig_permalink != $post_name_abridged && !$post->post_name ) {
+		//check if post is trashed
+		$orig_ID = $wpdb->get_var($wpdb->prepare("SELECT ID FROM $wpdb->posts WHERE post_name = %s AND post_status='trash';",$orig_permalink));
+		if ( $orig_ID ) {
+			?>
+			<div id="message" class="error">
+				<?php _e('There was a permalink conflict with an item in the trash. <a href="edit.php?post_status=trash&amp;post_type='.$post->post_type.'">View Trash</a>'); ?>
+			</div>
+			<?php
+		}
+	}
+
 	$post_name_html = '<span id="editable-post-name" title="' . $title . '">' . $post_name_abridged . '</span>';
 	$display_link = str_replace(array('%pagename%','%postname%'), $post_name_html, $permalink);
 	$view_link = str_replace(array('%pagename%','%postname%'), $post_name, $permalink);
@@ -1198,7 +1212,7 @@
 
 	$now = time();
 
-	update_post_meta( $post->ID, '_edit_lock', $now );	
+	update_post_meta( $post->ID, '_edit_lock', $now );
 }
 
 /**