The Roslyn .NET compiler provides C# and Visual Basic languages with rich code analysis APIs.
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sharwell Merge pull request #31761 from sharwell/focus-vs
Ensure Visual Studio has focus at the start of each new test
Latest commit 36b3aa2 Dec 13, 2018
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.github Remove PR template Jul 26, 2018
docs Async-streams: Disposal in async-iterator methods (#31527) Dec 13, 2018
eng Remove legacy RPS test from opt-prof run Dec 12, 2018
scripts Arcade layout (#31560) Dec 10, 2018
src Merge pull request #31761 from sharwell/focus-vs Dec 13, 2018
.editorconfig Arcade build scripts (#31511) Dec 6, 2018
.gitattributes Mark compiler generated files as generated for GitHub PRs (#31564) Dec 6, 2018
.gitignore Put Binaries in gitignore Dec 10, 2018
Build.cmd Arcade layout (#31560) Dec 10, 2018 Contributing page: reference Unix build instructions Oct 28, 2018
Compilers.sln Fix nesting in compilers.sln Oct 9, 2018
Compilers.slnf Add Compilers filter for Roslyn (#30880) Nov 10, 2018
Directory.Build.props Arcade layout (#31560) Dec 10, 2018
Directory.Build.rsp Add empty Directory.Build.rsp files Apr 9, 2018
Directory.Build.targets Arcade layout (#31560) Dec 10, 2018
License.txt Include the actual license text. Feb 6, 2015
NuGet.config Arcade build scripts (#31511) Dec 6, 2018 Update the badge layout Nov 30, 2018
Restore.cmd Arcade layout (#31560) Dec 10, 2018
Roslyn.sln Arcade layout (#31560) Dec 10, 2018
SourceBuild.sln NuGet packaging (#29408) Aug 27, 2018
THIRD-PARTY-NOTICES.txt Added DotNet global tool for code formatting. (#29403) Oct 10, 2018
Test.cmd Arcade layout (#31560) Dec 10, 2018
azure-pipelines-integration.yml Arcade layout (#31560) Dec 10, 2018
azure-pipelines-official.yml Fix directory path in createrunsettings.ps1 (#31692) Dec 12, 2018
azure-pipelines.yml Report an error if docker execution fails (#31696) Dec 12, 2018 Arcade layout (#31560) Dec 10, 2018
global.json Move VS MSBuild location to Arcade tools script Nov 27, 2018 Arcade layout (#31560) Dec 10, 2018 Arcade layout (#31560) Dec 10, 2018

Welcome to the .NET Compiler Platform ("Roslyn")

Desktop Unit Tests

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CoreClr Unit Tests

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Integration Tests

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Misc Tests

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Roslyn provides open-source C# and Visual Basic compilers with rich code analysis APIs. It enables building code analysis tools with the same APIs that are used by Visual Studio.

Language Design Discussion

We are now taking language feature discussion in other repositories:

Discussion about the transition of language design to the new repos is at

Download C# and Visual Basic

Want to start developing in C# and Visual Basic? Download Visual Studio 2017, which has the latest features built-in. There are also prebuilt Azure VM images available with Visual Studio 2017 already installed.

To install the latest release without Visual Studio, run one of the following nuget command lines:

nuget install Microsoft.Net.Compilers   # Install C# and VB compilers
nuget install Microsoft.CodeAnalysis    # Install Language APIs and Services

Daily NuGet builds of the project are also available in our MyGet feed:

See what's new with the C# and VB compilers.

Source code

Get started


Some of the best ways to contribute are to try things out, file bugs, and join in design conversations.

Looking for something to work on? The list of up for grabs issues is a great place to start.

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact with any additional questions or comments.

.NET Foundation

This project is part of the .NET Foundation along with other projects like the class libraries for .NET Core.