Index: src/wp-includes/comment-template.php
===================================================================
--- src/wp-includes/comment-template.php	(revision 41361)
+++ src/wp-includes/comment-template.php	(working copy)
@@ -1612,6 +1612,10 @@
 
 	$comment = get_comment( $comment );
 
+	if ( empty( $comment ) ) {
+		return;
+	}
+
 	if ( empty( $post ) ) {
 		$post = $comment->comment_post_ID;
 	}
Index: tests/phpunit/tests/comment/getCommentReplyLink.php
===================================================================
--- tests/phpunit/tests/comment/getCommentReplyLink.php	(revision 41361)
+++ tests/phpunit/tests/comment/getCommentReplyLink.php	(working copy)
@@ -26,4 +26,30 @@
 
 		$this->assertNull( get_comment_reply_link( $args ) );
 	}
+
+        /**
+         * @ticket 
+         */
+        public function test_should_return_null_when_depth_less_than_max_depth_and_comment_null_and_no_current_global_comment() {
+
+                $args = array(
+                        'depth'                 => 1,
+                        'max_depth'             => 2,
+                );
+
+		$comment = null;
+
+		// store current global comment
+		$tmp = $GLOBALS['comment'];
+
+		// remove global current comment
+		unset( $GLOBALS['comment'] );
+                
+		$this->assertFalse( isset( $GLOBALS['comment'] ) ); 
+                $this->assertNull( get_comment_reply_link( $args ), $comment );
+		
+		// restore current global comment
+		$GLOBALS['comment'] = $tmp;
+        }
+
 }