This extension adds Dafny 3 support to Visual Studio Code. If you require Dafny 2 support, consider using the legacy extension. This VSCode plugin requires the Dafny language server (shipped with the Dafny release since v3.1.0). The plugin will install it automatically upon first use.
- Compatible to Dafny 3.2.0.
- Compile and Run
.dfyfiles. - Verification as one types.
- Syntax highlighting thanks to sublime-dafny. See file
LICENSE_sublime-dafny.rstfor license. - Display CounterExample for failing proof.
- IntelliSense to suggest symbols.
- GoToDefinition to quickly navigate.
- Hover Information for symbols.
You can find examples below.
| Shortcut | Description |
|---|---|
Ctrl+Shift+B or ⇧+⌘+B |
Compile to .dll or, if there is a Main method, to .exe file |
F2 |
Rename a symbol |
F5 |
Compile and run, if the source file has a Main method |
F6 |
Compile with custom arguments |
F7 |
Show CounterExample |
F8 |
Hide CounterExample |
F9 |
Restarts the Dafny Language Server, also installs the latest language server version. |
The plugin requires at least .NET Core 5.0 (the ASP.NET Core 5.0 runtime to be more specific) to run the Dafny Language Server. Please download a distribution from Microsoft. When you first open a Dafny file, the extension will prompt you to install .NET Core manually. The language server gets installed automatically.
| Setting | Description | Default |
|---|---|---|
dafny.languageServerRuntimePath |
Absolute or relative path to the Dafny language server runtime (DafnyLS.dll). |
../../dafnyLanguageServer/DafnyLS.dll |
dafny.automaticVerification |
Optional string to control when the document should be verified (choose between never, onchange, and onsave. |
onchange |
dafny.languageServerLaunchArgs |
Optional array of strings as Dafny language server arguments. | [ ] |
dafny.compilerRuntimePath |
Absolute or relative path to the Dafny compiler (Dafny.dll). |
../../dafnyLanguageServer/Dafny.dll |
dafny.compilerArgs |
Optional array of strings as Dafny compilation arguments. | [ "/verifyAllModules", "/compile:1", "/spillTargetCode:1" ] |
dafny.compilerOutputDir |
Absolute or relative path to the compilation output directory. | bin |
dafny.dotnetExecutablePath |
Absolute path to the dotnet executable. Only necessary if dotnet is not in system PATH (you'll get an error if that's the case). | |
dafny.colorCounterExamples |
Customize the color (HEX) of Counter Examples. There are two default colors: for dark theme (#0d47a1, #e3f2fd) and light theme (#bbdefb, #102027). This color setting will override both defaults. | { "backgroundColor": null, "fontColor": null } |
dafny.terminalCommandPrefix |
The prefix to use when executing a command in the VS Code terminal. Defaults to & on windows. |
Please note that in this new plugin version "automatic verification" is always on and a language server side feature.
Here are a few impressions of the features.
On the first start, the plugin will install the Dafny language server automatically.
Whenever a syntax, semantic, or verification error is present, the plugin will inform the user.
Press F5 to compile and run the program.
Press F7 to show counterexamples.
Hover a symbol to get information about that symbol.
Type a dot to get a list of possible members of the accessed symbol.
If VSCode appears unresponsive, you may lower the verification frequency or disable it entirely.
Under certain circumstances, the extension appears to be stuck at Verifying.... Until now, this has only been observed for Mac OSX and occurs due to a stack overflow in the language server.
To overcome this issue, set the environment variable COMPlus_DefaultStackSize to a sufficiently large value before starting VSCode. For example:
# Increase the stack size
export COMPlus_DefaultStackSize=100000
# Launch VSCode
codeDafny for Visual Studio Code is an MIT licensed open-source project that lives from code contributions.
We welcome your help! For a description of how you can contribute, as well as a list of issues you can work on, please visit the Dafny-VSCode GitHub repository.