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dotnet
fsharp
F#2015–2026
dotnet / fsharp

fsharp

The F# compiler, F# core library, F# language service, and F# tooling integration for Visual Studio

41Distinct people
59Mentions
0Explicit recommenders
4.4KGitHub stars
REPOSITORY AT A GLANCE

What to know before exploring

What it is

The F# compiler, F# core library, F# language service, and F# tooling integration for Visual Studio

GitHub

Where it is used

No documented product use was verified in the last source check.

What people are saying

No recommendation phrase was found in the indexed comments.

No classified warning is attached to this page. Read the discussions before treating silence as approval.

Also in these discussions

Mentioned in the same Hacker News threads. That is not proof they are substitutes.

This week on Hacker News

Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 11:56:56 AM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year59 dated mentions

Observed mentions: 2015-01-14 17:42:32 UTC to 2026-05-14 14:09:36 UTC.

0369122015-01-01 00:00:00 UTC to 2016-01-01 00:00:00 UTC (exclusive): 11 mentions; 2 submissions, 9 comments20152016-01-01 00:00:00 UTC to 2017-01-01 00:00:00 UTC (exclusive): 7 mentions; 1 submissions, 6 comments2017-01-01 00:00:00 UTC to 2018-01-01 00:00:00 UTC (exclusive): 12 mentions; 3 submissions, 9 comments2018-01-01 00:00:00 UTC to 2019-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2019-01-01 00:00:00 UTC to 2020-01-01 00:00:00 UTC (exclusive): 5 mentions; 1 submissions, 4 comments2020-01-01 00:00:00 UTC to 2021-01-01 00:00:00 UTC (exclusive): 7 mentions; 1 submissions, 6 comments20202021-01-01 00:00:00 UTC to 2022-01-01 00:00:00 UTC (exclusive): 4 mentions; 0 submissions, 4 comments2022-01-01 00:00:00 UTC to 2023-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2023-01-01 00:00:00 UTC to 2024-01-01 00:00:00 UTC (exclusive): 3 mentions; 0 submissions, 3 comments2024-01-01 00:00:00 UTC to 2025-01-01 00:00:00 UTC (exclusive): 4 mentions; 1 submissions, 3 comments2025-01-01 00:00:00 UTC to 2026-01-01 00:00:00 UTC (exclusive): 3 mentions; 0 submissions, 3 comments2026-01-01 00:00:00 UTC to 2027-01-01 00:00:00 UTC (exclusive): 2 mentions; 2 submissions, 0 comments. Incomplete calendar period.2026*

* An incomplete calendar period is marked with an outlined bar. Its count is not directly comparable with a full period.

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges
UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
PeriodStart (UTC)End (exclusive, UTC)MentionsSubmissionsComments
20152015-01-01 00:00:00 UTC2016-01-01 00:00:00 UTC1129
20162016-01-01 00:00:00 UTC2017-01-01 00:00:00 UTC716
20172017-01-01 00:00:00 UTC2018-01-01 00:00:00 UTC1239
20182018-01-01 00:00:00 UTC2019-01-01 00:00:00 UTC000
20192019-01-01 00:00:00 UTC2020-01-01 00:00:00 UTC514
20202020-01-01 00:00:00 UTC2021-01-01 00:00:00 UTC716
20212021-01-01 00:00:00 UTC2022-01-01 00:00:00 UTC404
20222022-01-01 00:00:00 UTC2023-01-01 00:00:00 UTC101
20232023-01-01 00:00:00 UTC2024-01-01 00:00:00 UTC303
20242024-01-01 00:00:00 UTC2025-01-01 00:00:00 UTC413
20252025-01-01 00:00:00 UTC2026-01-01 00:00:00 UTC303
2026 (partial)2026-01-01 00:00:00 UTC2027-01-01 00:00:00 UTC220

From the project README

An excerpt from the repository, fetched Nov 13, 2026.

Read the project’s introduction
The F# compiler, F# core library, and F# editor tools You're invited to contribute to future releases of the F# compiler, core library, and tools. Development of this repository can be done on any OS supported by .NET. You will also need .NET SDK installed from here, exact version can be found in the global.json file in the root of the repository. Contributing Quickstart on Windows Build from the command line: build.cmd The build depends on an installation of Visual Studio. To build the compiler without this dependency use: build.cmd -noVisualStudio After it's finished, open either FSharp.slnx or VisualFSharp.slnx in your editor of choice. The latter solution is larger but includes the F# tools for Visual Studio and its associated infrastructure. Quickstart on Linux or macOS Build from the command line: ./build.sh After it's finished, open FSharp.slnx in your editor of choice. Documentation for contributors The Compiler Documentation is essential reading for any larger contributions to the F# compiler codebase and contains links to learning videos, architecture diagrams, and other resources. The same docs are also published as The F# Compiler Guide. It also contains the public searchable docs for FSharp.Compiler.Service component. See DEVGUIDE.md for more details on configurations for building the codebase. In practice, you only need to run build.cmd/build.sh. See TESTGUIDE.md for information about the various test suites in this codebase and how to run them individually. Documentation for F# community The F# Documentation is the primary documentation for F#. The source for the content is here. The F# Language Design Process is the fundamental design process for the language, from suggestions to completed RFCs. There are also tooling RFCs for some topics where cross-community co-operation and visibility are most useful. The F# Language Specification is an in-depth description of the F# language. This is essential for understanding some behaviors of the F# compiler and some of the rules within the compiler codebase. For example, the order and way name resolution happens are specified here, which greatly impacts how the code in Name Resolutions works and why certain decisions are made. No contribution is too small Even if you find a single-character typo, we're happy to take the change! Although the codebase can feel daunting for beginners, we and other contributors are happy to help you along. Not sure where to contribute? Look at the curated list of issues asking for help. If you want to tackle any of those, use the comments section of the chosen issue to indicate interest and feel free to ask for initial guidance. We are happy to help with resolving outstanding issues while making a successful PR addressing the issue. The issues in this repository can have big differences in the complexity for fixing them. Are you getting started? We do have a label for good first issues as well. Per-build NuGet packages 7.0.40x series FSharp.Compiler.Service 43.7.400-preview <add key="fsharp-prerelease" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet7/nuget/v3/index.json" /> 8.0.10x series FSharp.Compiler.Service 43.8.100-preview <add key="fsharp-prerelease" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet8/nuget/v3/index.json" /> NOTE: Official NuGet releases of FCS and FSharp.Core are synched with SDK releases (on purpose - we want to be in sync). Nightly packages release to Azure feeds on every successful insertion. Branches These are the branches in use: main Almost all contributions go here. Able to be built, installed and used in the latest public Visual Studio release. May contain updated F# features and logic. Used to build nightly VSIX (see above). release/dev15.9 Long-term servicing branch for VS 2017 update 15.9.x. We do not expect to service that release, but if we do, that's where the changes will go. release/dev17.x Latest release branch for the particular point release of Visual Studio. Incorporates features and fixes from main up to a particular branch point, then selective cherry-picks. May contain new features that depend on new things or fixes in the corresponding forthcoming Visual Studio release. Gets integrated back into main once the corresponding Visual Studio release is made. F# language and core library evolution Evolution of the F# language and core library follows a process spanning two additional repositories. The process is as follows: Use the F# language suggestions repo to search for ideas, vote on ones you like, submit new ideas, and discuss details with the F# community. Ideas that are "approved in principle" are eligible for a new RFC in the F# language design repo. This is where the technical specification and discussion of approved suggestions go. Implementations and testing of an RFC are submitted to this repository. License This project is subject to the MIT License. A copy of this license is in License.txt. Code of Conduct This project has adopted the Contributor Covenant code of conduct to clarify expected behavior in our community. You can read it at CODE_OF_CONDUCT. Get In Touch Members of the F# Software Foundation are invited to the FSSF Slack. You can find support from other contributors in the #compiler and #editor-support channels. Additionally, you can use the #fsharp tag on Twitter if you have general F# questions, including about this repository. Chances are you'll get multiple responses. About F# If you're curious about F# itself, check out these links: What is F# Get started with F# F# Software Foundation F# Testimonials Contributors ✨ F# exists because of these wonderful people: Made with contrib.rocks.
Read the full README on GitHub

What Hacker News says

59 sources
It's not the same. Recently Opus 4.5 diagnosed and fixed a bug in the F# compiler for me, for example (https://github.com/dotnet/fsharp/pull/19123). The root cause is pretty subtle and very non-obvious, and of course the critical snippet of the stack trace `at FSharp.Compiler.Symbols.FSharpExprConvert.GetWitnessArgs` has no hits on Google other than my own bug report. I would have been completely lost fixing it.
In The highest quality codebase
Tailcalls is something that a language compiler that targets VM bytecode cannot easily address by itself and ideally needs cooperation from the VM. I'm not aware of implementation details of either Clojure or Kotlin but if it is anything like F#, then I would really not hold tailcalls against either of them. In order to effectively support FP languages, CIL specification defines tail. prefix for call, calli and callvirt opcodes, and CoreCLR fully supports it except scenarios outlined by the spec. Does JVM bytecode specification have something like this? Edit: Turns out F# compiler does additional heavy lifting besides emitting the prefix https://github.com/dotnet/fsharp/blob/main/docs/large-inputs...
In How does it feel to test a compiler?
The last time I gave F# a shot, I tried to write a simple Telegram bot in it. Just to test how much I would actually benefit from the .NET ecosystem, I chose to use a C# wrapper for the Telegram API. Suddenly I had to handle null references and exceptions everywhere (it's in this regard even worse than Rust, where I'm guaranteed to get Options and Results). I know proper support for C# T? type interop is in the works (https://github.com/dotnet/fsharp/pull/15181), but really it seemed to me that too few cared about F# to get it landed in a reasonable timeframe. I'd really love to see a pragmatic FP language with a reasonable amount of libs to choose from (both natively and via interop without much effort), but F# was a bit far from that description IMO.
In Why F# evangelism isn't working (2015)

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