Index: wp-includes/canonical.php
===================================================================
--- wp-includes/canonical.php	(revision 50671)
+++ wp-includes/canonical.php	(working copy)
@@ -237,6 +237,14 @@
 				$redirect_url = get_attachment_link();
 				$redirect_obj = get_post();
 			}
+		} elseif ( is_single() && ! empty( get_query_var( 'p' ) ) && ! $redirect_url ) {
+			
+			$redirect_url = get_permalink( get_query_var( 'p' ) );
+			$redirect_obj = get_post( get_query_var( 'p' ) );
+
+			if ( $redirect_url ) {
+				$redirect['query'] = remove_query_arg( array( 'p', 'post_type' ), $redirect['query'] );
+			}
 		} elseif ( is_single() && ! empty( $_GET['p'] ) && ! $redirect_url ) {
 			$redirect_url = get_permalink( get_query_var( 'p' ) );
 			$redirect_obj = get_post( get_query_var( 'p' ) );