Verus-Analyzer

Verus-analyzer is a version of rust-analyzer that has been modified to provide IDE support for writing Verus code and proofs, including syntax support and various IDE features.

WARNING!

This software is experimental and subject to change; some features are likely broken. At present, it works best on small, self-contained Verus projects. Anything more complex will likely fail. You may file issues, but we do not currently have dedicated engineering support for verus-analyzer, so your issue may not be addressed. Pull requests with fixes are always welcome, although it is unlikely they will be reviewed immediately.

Quick Start

The intended use of verus-analyzer is as a drop-in replacement for rust-analyzer.

1. Compile binary

1. Obtain the verus-analyzer source

$ git clone https://github.com/verus-lang/verus-analyzer.git
$ cd verus-analyzer

2. Compile the verus-analyzer binary

$ cargo xtask dist

3. Unzip and make the binary executable This step is dependent on your operating system.

MacOS:

$ gunzip ./dist/verus-analyzer-aarch64-apple-darwin.gz
$ chmod +x ./dist/verus-analyzer-aarch64-apple-darwin

Linux:

$ gunzip dist/verus-analyzer-x86_64-unknown-linux-gnu.gz
$ chmod +x dist/verus-analyzer-x86_64-unknown-linux-gnu

Windows:

Locate the generated zip file dist\verus-analyzer-x86_64-pc-windows-msvc.zip and extract it (e.g., through right-click + extract all). Then you should see the file dist\verus-analyzer-x86_64-pc-windows-msvc\rust-analyzer.exe that you are going to use as the verus-analyzer binary.

2. IDE Setup

To use verus-analyzer in your IDE (e.g., VS Code, EMACS or VIM) you need to configure your IDE to use the compiled verus-analyzer binary instead of rust-analyzer for *.rs files.

EMACS Setup

TODO

VIM Setup

TODO

VS Code Setup

You will need to install the rust-analyzer extension

code --install-extension rust-lang.rust-analyzer

Then you can configure the rust-analyzer extensions to use the verus-analyzer binary that you compiled. You can do so by either

1. Use a new VS Code Workspace and specify the settings, or
2. Adding the settings of your existing workspace through the .vscode/settings.json files.

You will need to add the following settings:

{
  "rust-analyzer.server.path": "FULL-PATH-TO-THE-VERUS-ANALYZER-BINARY",
  "rust-analyzer.checkOnSave": false
}

Note: the path must be the absolute path to the generated binary. We disable cargo-check by setting rust-analyzer.checkOnSave to false.

When saving the file, you may get prompted to reload the rust-analyzer server.

When opening a Verus project with the created workspace settings or open a folder with the .vscode/settings.json, it will use the custom binary. Otherwise, it will keep using the original rust-analyzer binary.

Remote - SSH If you are using VS code on a remote machine make sure to setup verus-analyzer on the remote machine and configure the settings as mentioned above with the paths on the remote machine.

3. Requirements for IDE functionalities

There is a requirement for the IDE functionalities to work. The requirement is that rust-analyzer expects a standard Rust project layout and the metadata(Cargo.toml) file.

Rust-analyzer scans the project root(lib.rs or main.rs) and all files that are reachable from the root. If the file you are working on is not reachable from the project root, most of the IDE functionalities like "goto definition" will not work. For example, when you have a file named foo.rs next to main.rs, and did not import foo.rs in main.rs(i.e., did not add mod foo on top of main.rs), the IDE functionalities will not work for foo.rs.

We also need Cargo.toml files as in standard Rust projects. For a small project, you could start with cargo new, and it automatically generated the Cargo.toml file. For a larger project, you could use workspace to manage multiple crates.

4. Running Verus in VS Code (optional)

This is an experimental feature that allows you to run Verus inside VS Code by saving a file. To run Verus inside VS Code, please remove "rust-analyzer.checkOnSave": false from the .code-workspace file, and add "rust-analyzer.checkOnSave.overrideCommand". The value of "rust-analyzer.checkOnSave.overrideCommand" should be a list that contains the Verus binary. Please use the absolute path to the Verus binary that is built by vargo.

For example, add the following entries to your workspace settings or the .vscode/settings.json file.

"rust-analyzer.server.path": "ABSOLUTE-PATH-TO-THE-VERUS-ANALYZER-BINARY",
"rust-analyzer.checkOnSave.overrideCommand": [
    "ABSOLUTE-PATH-TO-VERUS-BINARY", //  e.g., /home/verus-username/verus/source/target-verus/(debug|release)/verus
]
}

To provide extra arguments, add extra_args at [package.metadata.verus.ide] inside your Cargo.toml file. For example, if you want to run Verus with --crate-type=dylib --expand-errors, you could add the following at the bottom of your Cargo.toml file.

[package.metadata.verus.ide]
extra_args = "--crate-type=dylib --expand-errors"

Please set only one of rust-analyzer.checkOnSave.overrideCommand and rust-analyzer.checkOnSave in the .code-workspace file, depending as to whether you want to run Verus inside VS Code or not.

---

Functionalities and Details

1.Syntax

We extended rust-analyzer's grammar for Verus-specific syntax. This custom rust-analyzer highlights reserved Verus keywords (e.g., spec, proof, requires, ensures). If a user types prof instead of proof, a syntax error will be generated for it.

2.IDE functionalities

You can find more documents for IDE functionalities on the following links.

• Go to Definition
• Go to Type Declaration
• Find all References
• Hover

2.1 TODOs for IDE functionalities

• Code scanning is incomplete for Verus-specific items. To be specific, requires/ensures/decreases/invariant/assert-by-block/assert-forall-block are not fully scanned for IDE purposes (e.g., might not be able to "goto definition" of the function used in requires/ensures, "find all references" might omit occurrences inside requires/ensures).

• Although Verus' custom operators are parsed, thye are not registered for IDE purposes. For example, type inference around such operators might not work. (e.g., A ==> B is parsed as implies(A, B), but the IDE might not be able to infer that A and B are Boolean).

• builtin and vstd are not scanned. For example, the builtin types like int and nat could be shown as unknown. Auto completion for vstd might not work.

---

Limitations

• This is experimental software and subject to change.
• It is intended to be used only for Verus code. (For Rust code, you can use the original binary by opening the project without the .code-workspace file, which is just using "open folder" in VS Code)
• Multiple features of rust-analyzer might be broken or missing.
• Syntax might not be updated to the latest version of Verus.

Misc

• rust-analyzer: Clear flycheck diagnostics command can be used to clear the error messages in VS Code
• Developer: Reload Window can be used to reload VS Code and the verus-analyzer server instead of closing and reopening VS Code
• Setting "rust-analyzer.diagnostics.disabled": ["syntax-error"] in the workspace setting can disable the syntax error messages in VS Code. You could also add unresolved-module to the above list to disable the error message for unresolved modules.
• There is no proper support for buildin/vstd. However, in your project's Cargo.toml file, you can add vstd in dependencices or dev-dependencies, which might make verus-analyzer scan vstd and builtin. For example,

[dependencies]
vstd = { path = "../verus/source/vstd"}  # assuming verus and the project are in the same directory

---

Proof Actions (Optional)

Proof actions are an experimental feature to assist developers when debugging proof failures.

Compilation

Compile Verus analyzer by following the steps below. These steps are similar to the basic version with the exception of the extra flag used in step 3.

1. Clone the repository: git clone https://github.com/verus-lang/verus-analyzer.git
2. cd verus-analyzer
3. Compile the rust-analyzer binary: cargo xtask dist --proof-action
4. Unzip the generated file (e.g., gunzip ./dist/verus-analyzer-aarch64-apple-darwin.gz)
5. Make it executable (e.g., chmod +x ./dist/verus-analyzer-aarch64-apple-darwin)

Prerequisites

• Follow the directions for 4. Running Verus in VS Code (optional)
• verusfmt You can install verusfmt using:

cargo install verusfmt --locked

You can then use which verusfmt to get the absolute path to it.

Configuration

The "settings" entry in the .code-workspace file needs some additional configuration to provide environment variables for the verus-analyzer binary. In particular, we need to define: "VERUS_BINARY_PATH", "TMPDIR", and "VERUS_FMT_BINARY_PATH".

"rust-analyzer.server.extraEnv": {
        "VERUS_BINARY_PATH" : "ABSOLUTE-PATH-TO-VERUS-BINARY", //  e.g., /home/verus-username/verus/source/target-verus/(debug|release)/verus
        "TMPDIR": "ABSOLUTE-PATH-TO-TMP-DIR", // e.g., "/home/verus-username/.tmpdir"
        "VERUS_FMT_BINARY_PATH" : "ABSOLUTE-PATH-TO-VERUS-FMT", // e.g., "/home/verus-username/.cargo/bin/verusfmt"
}

Hence, the final configuration for settings might look like the following.

"settings": {
        "rust-analyzer.server.path": "ABSOLUTE-PATH-TO-THE-VERUS-ANALYZER-BINARY",
        "rust-analyzer.server.extraEnv": {
                "VERUS_BINARY_PATH" : "ABSOLUTE-PATH-TO-VERUS-BINARY", //  e.g., /home/verus-username/verus/source/target-verus/(debug|release)/verus
                "TMPDIR": "ABSOLUTE-PATH-TO-TMP-DIR", // e.g., "/home/verus-username/.tmpdir"
                "VERUS_FMT_BINARY_PATH" : "ABSOLUTE-PATH-TO-VERUS-FMT", // e.g., "/home/verus-username/.cargo/bin/verusfmt"
        },
        "rust-analyzer.checkOnSave.overrideCommand": [
            "ABSOLUTE-PATH-TO-VERUS-BINARY", //  e.g., /home/verus-username/verus/source/target-verus/(debug|release)/verus
        ],
}

Proof Action Demo

Source code