VeriFast

What VeriFast is

VeriFast is a free, MIT-licensed research prototype for modular formal verification of C, Rust, and Java programs. It checks annotations expressing preconditions and postconditions in separation logic. Specifications can also use inductive datatypes, primitive recursive pure functions, and abstract separation logic predicates. Developers can write lemma functions as proofs; VeriFast checks that they terminate and have no side effects. The project describes verification time as predictable and low because the verifier and its SMT solver require little search. It offers a desktop IDE, command-line tool, and Visual Studio Code extension. The extension can verify the active C, Java, or Rust file and show symbolic execution failures with highlighted source locations. It requires a separate VeriFast installation and a configured path to the command-line tool. Nightly binaries and named releases are available, with build instructions for Windows, Linux, and macOS. The project says its CI workflow creates GitHub Artifact Attestations for binary packages. The VeriFast Docs and Rust reference are under construction, and informal community chat is available through its Zulip chatroom.

Who it suits

VeriFast suits developers working with C, Rust, or Java who want to verify annotated programs. It is intended for users comfortable with a research prototype and, for the VS Code extension, a separate installation and configuration.

Limits

The VS Code extension requires a separate VeriFast installation and a configured path to its command-line tool. The VeriFast Docs and Rust reference are under construction.

Getting started

1. Visit the VeriFast GitHub project.
2. Download a nightly binary or named release, or follow the build instructions for Windows, Linux, or macOS.
3. Install VeriFast locally for self-hosted use.
4. Choose the desktop IDE or command-line tool, or install the VS Code extension.
5. If using the extension, configure its path to the VeriFast command-line tool.

Verdict

VeriFast offers several ways to check separation-logic specifications across three programming languages. Its prototype status and unfinished documentation are relevant considerations for adoption.