Leon is an automated system for verifying, repairing, and synthesizing functional Scala programs.
The system can be tried out online, with no installation required, at the following link:
Leon source code is publicly available on github:
https://github.com/epfl-lara/leon
The github repository contains the documentation that can be built in various formats, including in particular HTML.
A snapshot of this documentation, including a tutorial, is also available from http://leon.epfl.ch, please check