FSharpLintAnalyzerShim 0.2.0-alpha.1

FSharpLintAnalyzerShim

A thin adapter that exposes all 97 FSharpLint rules as a single FSharp.Analyzers.SDK [<CliAnalyzer>].

This lets you run FSharpLint alongside custom project analyzers in one fsharp-analyzers invocation, eliminating duplicate project loading.

How it works

The shim:

1. Discovers fsharplint.json by walking up from each file's directory (cached per directory)
2. Converts the Analyzer SDK's CliContext into FSharpLint's ParsedFileInformation
3. Calls FSharpLint.Application.Lint.lintParsedFile
4. Maps each LintWarning to an Analyzer SDK Message

All rule logic lives in FSharpLint.Core -- this project contains no rules of its own.

Setup

Prerequisites

• .NET 10 SDK
• fsharp-analyzers CLI tool: dotnet tool install -g fsharp-analyzers
• Paket for dependency management: dotnet tool install -g paket

Build

paket install
dotnet build -c Release

Run

fsharp-analyzers \
  --project path/to/YourProject.fsproj \
  --analyzers-path path/to/FSharpLintAnalyzerShim/bin/Release/net10.0/

You can combine with other analyzer paths:

fsharp-analyzers \
  --project path/to/YourProject.fsproj \
  --analyzers-path path/to/FSharpLintAnalyzerShim/bin/Release/net10.0/ \
  --analyzers-path path/to/YourOtherAnalyzers/bin/Release/net10.0/

Configuration

Place a fsharplint.json anywhere in the file's directory hierarchy. The shim walks up from each source file to find the nearest config, just like FSharpLint itself.

If no config file is found, FSharpLint's built-in default configuration is used.

See the FSharpLint documentation for config format.

Diagnostics

All diagnostics use the standard FSharpLint rule codes (FL0001 through FL0097). Severity is always Warning. Suggested fixes from FSharpLint are passed through as Analyzer SDK Fix records.

If FSharpLint encounters an internal error (which it normally swallows silently), the shim surfaces it as an FL0000 Info diagnostic.

Rule suppression

FSharpLint's built-in suppression mechanisms work through the shim with no extra configuration:

Inline comments -- disable rules per-line or per-section:

// fsharplint:disable-next-line RecordFieldNames
type Foo = { bar: int }

// fsharplint:disable MaxLinesInFunction
// ... long function ...
// fsharplint:enable MaxLinesInFunction

Supported directives:

Omit the rule name to apply to all rules.

fsharplint.json -- disable rules globally by setting "enabled": false on any rule. See the FSharpLint documentation for the full config format.

Dependencies

FSharpLint.Core is pulled from michaelglass/FSharpLint (perf/two-phase-lint-api branch) via Paket git dependency. This branch merges Numpsy's fcs10 branch, which updated FSharpLint to FSharp.Compiler.Service 43.x -- huge thanks to Numpsy (Richard Webb) for that work. The perf/two-phase-lint-api branch pins FCS to 43.10.101 for compatibility with the fsharp-analyzers CLI v0.36.0 and adds a two-phase lint API for analyzer integration.

Development

mise run check    # build + test
mise run test     # tests only
mise run build    # build only

Tests

• ConfigDiscoveryTests -- config file discovery, directory walking, caching
• WarningMappingTests -- LintWarning-to-Message field mapping, fix mapping, severity
• IntegrationTests -- end-to-end: lint source with violations, verify mapped output