dotnet/fsharp

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

Stars: 4.3k
Forks: 876
Open beginner issues: 0
Indexed issues: 1.1k
Avg merge: 4d 22h
Merged PRs (30d): 144

Dominant language: F#
License: MIT
Last GitHub push: Sep 14, 2026
Latest indexed: Sep 15, 2026
Contributing guide: Contributing guide
Code of conduct: Code of conduct
Beginner labels: help wanted good first issue

Open All

1129 open issues indexed

Offer `interface` keyword for classes in IntelliSense Open

Area-LangService-AutoComplete Bug Impact-Medium Regression

dotnet/fsharp#15996 · 5 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Suboptimal code generated when pattern matching a tuple in a lambda parameter Open

Area-Compiler-CodeGen Feature Improvement Theme-Performance

dotnet/fsharp#16037 · 0 comments · 3 reactions · 0 assignees · Indexed Sep 15, 2026
IDE code analysis starts to freeze on large files affecting Intellisense, text coloring, tooltips and responsiveness Open

Area-Compiler-Service Feature Improvement Theme-Performance

dotnet/fsharp#16050 · 32 comments · 3 reactions · 0 assignees · Indexed Sep 15, 2026
Code completion doesn't work inside Or pattern Open

Area-LangService-AutoComplete Bug Impact-Low Regression

dotnet/fsharp#16055 · 6 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
FSI #r Supports NuGet interactive. Open

Area-FSI Feature Request

dotnet/fsharp#16057 · 2 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Prohibit `OptionaArgumentAttribute` on interface members Open

Bug Impact-Medium Needs-design

dotnet/fsharp#16059 · 10 comments · 0 reactions · 1 assignee · Indexed Sep 15, 2026
Prepare F# 201 content Open

dotnet/fsharp#16076 · 0 comments · 0 reactions · 1 assignee · Indexed Sep 15, 2026
Telemetry exception in VS Open

AI-thinks-windows-only Area-VS Bug Impact-Low Theme-Telemetry

dotnet/fsharp#16083 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 15, 2026
It is not possible to pass command-line arguments starting with an at-sign to fsx scripts run with "dotnet fsi" Open

Area-Documentation

dotnet/fsharp#16092 · 8 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
`MembersFunctionsAndValues` returns no auto property symbol in interface implementation Open

Area-Compiler-Service Bug Impact-Low

dotnet/fsharp#16099 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
F# compiler doesn't emit default parameter value for some types Open

Area-Compiler-CodeGen Feature Request Needs-design

dotnet/fsharp#16112 · 5 comments · 2 reactions · 0 assignees · Indexed Sep 15, 2026
VS Coloring sometimes resets Open

AI-thinks-windows-only Area-VS-Editor Bug Impact-Medium Needs-Confirmation Needs-More information Needs-Repro

dotnet/fsharp#16130 · 2 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
VerificationException on runtime, due to upcast to obj inside the task state machine Open

Area-Compiler-StateMachines Bug Impact-Low Regression

dotnet/fsharp#16154 · 4 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
AddOpen opens the wrong namespace for IEnumerator Open

Area-LangService-CodeFixes Bug good first issue help wanted Impact-Medium

dotnet/fsharp#16155 · 1 comment · 1 reaction · 0 assignees · Indexed Sep 15, 2026
CodeFix for adding missing '=' (in case of FS0010) suggests non-parseable code. Open

Area-LangService-CodeFixes Bug Impact-Medium

dotnet/fsharp#16159 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Compiler eagerly imports IL type defs from unopened namespaces consisting of a single name Open

Area-Compiler-Optimization Bug Impact-Medium

dotnet/fsharp#16166 · 1 comment · 3 reactions · 0 assignees · Indexed Sep 15, 2026
TryFinallyAsync implementation ignores potential exceptions in TryFinally Open

Area-Compiler-StateMachines Breaking-change Bug Impact-Medium

dotnet/fsharp#16189 · 1 comment · 2 reactions · 0 assignees · Indexed Sep 15, 2026
Entities from external assemblies are not navigable in tooltips Open

Area-LangService-ToolTips Feature Request

dotnet/fsharp#16196 · 2 comments · 4 reactions · 0 assignees · Indexed Sep 15, 2026
One-click experience for signature file generation Open

Area-Compiler-SigFileGen Feature Request

dotnet/fsharp#16214 · 0 comments · 3 reactions · 0 assignees · Indexed Sep 15, 2026
Tracking: Issues & suggestions solvable with Analyzers SDK Open

Analyzers Tracking

dotnet/fsharp#16219 · 17 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
False positive `Open declaration can be removed` when having records with the same name Open

Area-LangService-CodeFixes Bug Impact-Low

dotnet/fsharp#16226 · 1 comment · 2 reactions · 0 assignees · Indexed Sep 15, 2026
False positive `Open declaration can be removed` when using extension for builder Open

Area-LangService-CodeFixes Bug Impact-Low

dotnet/fsharp#16227 · 0 comments · 2 reactions · 0 assignees · Indexed Sep 15, 2026
SIMD vectorisation Open

Area-Library Feature Request

dotnet/fsharp#16230 · 17 comments · 3 reactions · 0 assignees · Indexed Sep 15, 2026
Refactoring for _.Property / _.MethodCall() / _.IndexerAccess[idx] shorthand for accessor functions Open

Analyzers Area-LangService-CodeFixes Feature Request

dotnet/fsharp#16234 · 20 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Span IL gen produces 2 get_Item calls for span[i] <- span[i] + 1 Open

Area-Compiler-CodeGen Feature Improvement

dotnet/fsharp#16245 · 0 comments · 1 reaction · 0 assignees · Indexed Sep 15, 2026
Optimization for string interpolation - simple scenarios: unfolding constants and lowering to concatenation Open

Area-Compiler-Optimization Feature Improvement Theme-Performance

dotnet/fsharp#16247 · 6 comments · 4 reactions · 1 assignee · Indexed Sep 15, 2026
Parenthesized/double unit literal `()` → `(())` required in certain scenarios Open

Area-Diagnostics Bug Impact-Low

dotnet/fsharp#16254 · 8 comments · 2 reactions · 0 assignees · Indexed Sep 15, 2026
Inconsistent parenthesization requirements for single-argument additional constructors (with `new`) Open

Area-Compiler-Syntax Feature Improvement

dotnet/fsharp#16257 · 2 comments · 0 reactions · 1 assignee · Indexed Sep 15, 2026
Warn about the use of non-generic collections Open

Analyzers Area-Diagnostics Feature Request

dotnet/fsharp#16259 · 3 comments · 1 reaction · 0 assignees · Indexed Sep 15, 2026
parser recovery is not great for `Ident.(` and the tooling doesn't help typing qualified custom operators Open

Area-Compiler-Syntax Feature Improvement

dotnet/fsharp#16260 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
track `LanguageFeatures.SupportsFeature` calls in compilation/type checking environment Open

Area-Diagnostics Feature Request

dotnet/fsharp#16274 · 2 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Exception in VS in `itemKeyStore` Open

AI-thinks-windows-only Area-VS-Editor Bug Impact-Low Theme-Telemetry

dotnet/fsharp#16275 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Document Outline view in Visual Studio show nothing for F# Open

Area-VS-Editor Feature Request

dotnet/fsharp#16288 · 5 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
`[editor feature]` hitting new line amidst a single line comment should put the remaining of the line after `// ` of the inserted new line Open

Area-VS-Editor Feature Request

dotnet/fsharp#16289 · 0 comments · 1 reaction · 0 assignees · Indexed Sep 15, 2026
Incorrect codegen for Debug build with srtp and mutable struct Open

Area-Compiler-CodeGen Bug Impact-Low

dotnet/fsharp#16292 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 15, 2026
FS3559 raised with PrintfFormat Open

Bug Impact-Low Needs-More information

dotnet/fsharp#16296 · 2 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Make sure color themes handling in VS is up to date Open

AI-thinks-windows-only Area-VS-Editor Bug Impact-Medium

dotnet/fsharp#16300 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 15, 2026
function-keyword debug improvements Open

Area-Debug Bug Feature Request

dotnet/fsharp#16306 · 1 comment · 3 reactions · 0 assignees · Indexed Sep 15, 2026
Cannot supply `typeof<>` to attribute constructor Open

Area-Compiler-Checking Area-Compiler-Checking-Attributes Bug Triage-Investigate

dotnet/fsharp#16344 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
Building a fsharp project using MSBUILD with in the projectlevel the warninglevel set to 5 will result in a false error Open

Area-Diagnostics Bug Impact-Low

dotnet/fsharp#16355 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
[FSharp.Editor] tooltips shows unnamed types when there is an error in a file / project which has type provider Open

Area-LangService-ToolTips Bug Impact-Low

dotnet/fsharp#16361 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
F# style extension methods with `[<Extension>]` attribute applied generate C# incompatible method names Open

Area-Compiler-CodeGen Bug Impact-Low

dotnet/fsharp#16362 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
[Parser recovery] DU type without `=` sign Open

Area-Compiler-Syntax Feature Improvement

dotnet/fsharp#16367 · 0 comments · 0 reactions · 1 assignee · Indexed Sep 15, 2026
DotnetFscCompilerPath property is wrapped into double quotes Open

Area-ProjectsAndBuild Bug Impact-Low

dotnet/fsharp#16375 · 2 comments · 1 reaction · 0 assignees · Indexed Sep 15, 2026
Significant allocations writing F# types using Console.Logger Open

Area-Compiler-CodeGen Feature Improvement Theme-Performance

dotnet/fsharp#16378 · 6 comments · 0 reactions · 0 assignees · Indexed Sep 15, 2026
dotnet fsi fails with FS0239: An implementation of the file or module 'SOME MODULE NAME FSI GENERATES' has already been given" when switching from `fsi.exe`(.net framework) to `dotnet fsi` Open

Bug Impact-Low Triage-Investigate

dotnet/fsharp#16384 · 0 comments · 0 reactions · 1 assignee · Indexed Sep 15, 2026
Unused opens/values false positives with type check errors Open

Area-Compiler-Checking Area-LangService-UnusedOpens Bug Impact-Low

dotnet/fsharp#16415 · 0 comments · 1 reaction · 0 assignees · Indexed Sep 15, 2026
Generic AddHttpClient selected instead of non-generic Open

Area-Compiler-Checking Area-Compiler-Checking-Overloads Feature Improvement Needs-More information

dotnet/fsharp#16422 · 5 comments · 1 reaction · 0 assignees · Indexed Sep 15, 2026
Revisit type-checking logic Open

Area-Compiler-Checking Feature Request Needs-design

dotnet/fsharp#16436 · 11 comments · 3 reactions · 0 assignees · Indexed Sep 15, 2026
Consider fuzzing syntax changes Open

Engineering Needs-design

dotnet/fsharp#16448 · 0 comments · 3 reactions · 0 assignees · Indexed Sep 15, 2026

dotnet/fsharp

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