Latest version incompatible with .NET 9

[b-hodge]

Description

We have been using FSharpLint with a .NET project targeting .NET version 8.0.401.

After upgrading our project to .NET version 9.0.101, FSharpLint no longer works.

Repro steps

Working correctly with .NET 8.0:

❯ movableink/scratch/fsharplint-8.0 dotnet --version
8.0.401

❯ movableink/scratch/fsharplint-8.0 dotnet new classlib -lang "F#" -o src/Library
The template "Class Library" was created successfully.

Processing post-creation actions...
Restoring /Users/bhodge/code/movableink/scratch/fsharplint-8.0/src/Library/Library.fsproj:
  Determining projects to restore...
  Restored /Users/bhodge/code/movableink/scratch/fsharplint-8.0/src/Library/Library.fsproj (in 361 ms).
Restore succeeded.



❯ movableink/scratch/fsharplint-8.0 dotnet fsharplint lint src/Library/Library.fsproj
========== Linting /Users/bhodge/code/movableink/scratch/fsharplint-8.0/src/Library/obj/Debug/net8.0/Library.AssemblyInfo.fs ==========
========== Finished: 0 warnings ==========
========== Linting /Users/bhodge/code/movableink/scratch/fsharplint-8.0/src/Library/obj/Debug/net8.0/.NETCoreApp,Version=v8.0.AssemblyAttributes.fs ==========
========== Finished: 0 warnings ==========
========== Linting /Users/bhodge/code/movableink/scratch/fsharplint-8.0/src/Library/Library.fs ==========
========== Finished: 0 warnings ==========
========== Summary: 0 warnings ==========

Failing for a project targeting .NET 9.0:

❯ movableink/scratch/fsharplint-9.0 dotnet --version
9.0.101

❯ movableink/scratch/fsharplint-9.0 dotnet new classlib -lang "F#" -o src/Library
The template "Class Library" was created successfully.

Processing post-creation actions...
Restoring /Users/bhodge/code/movableink/scratch/fsharplint-9.0/src/Library/Library.fsproj:
Restore succeeded.



❯ movableink/scratch/fsharplint-9.0 dotnet fsharplint lint src/Library/Library.fsproj
Lint failed while analysing src/Library/Library.fsproj.
Failed with: Could not load file or assembly 'System.Runtime, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified.

Stack trace:    at Ionide.ProjInfo.ProjectLoader.loadProject(String path, BinaryLogGeneration binaryLogs, FSharpList`1 globalProperties)
   at Ionide.ProjInfo.ProjectLoader.getProjectInfo(String path, FSharpList`1 globalProperties, BinaryLogGeneration binaryLogs, FSharpList`1 customProperties) in /_//src/Ionide.ProjInfo/Library.fs:line 842
   at <StartupCode$Ionide-ProjInfo>.$Library.loadProject@1176(WorkspaceLoader __, FSharpList`1 customProperties, BinaryLogGeneration binaryLogs, Dictionary`2 cache, String p) in /_//src/Ionide.ProjInfo/Library.fs:line 1177
   at <StartupCode$Ionide-ProjInfo>.$Library.loadProjectList@1213(WorkspaceLoader __, FSharpList`1 customProperties, BinaryLogGeneration binaryLogs, Dictionary`2 cache, FSharpList`1 projectList) in /_//src/Ionide.ProjInfo/Library.fs:line 1233
   at Ionide.ProjInfo.WorkspaceLoader.Ionide.ProjInfo.IWorkspaceLoader.LoadProjects(FSharpList`1 projects, FSharpList`1 customProperties, BinaryLogGeneration binaryLogs) in /_//src/Ionide.ProjInfo/Library.fs:line 1241
   at FSharpLint.Application.Lint.getProjectInfo(String projectFilePath, ToolsPath toolsPath) in /home/runner/work/FSharpLint/FSharpLint/src/FSharpLint.Core/Application/Lint.fs:line 302
   at FSharpLint.Application.Lint.lintProject$cont@397(OptionalLintParameters optionalParams, String projectFilePath, ToolsPath toolsPath, Unit unitVar) in /home/runner/work/FSharpLint/FSharpLint/src/FSharpLint.Core/Application/Lint.fs:line 441
   at FSharpLint.Application.Lint.lintProject(OptionalLintParameters optionalParams, String projectFilePath, ToolsPath toolsPath) in /home/runner/work/FSharpLint/FSharpLint/src/FSharpLint.Core/Application/Lint.fs:line 396
   at FSharpLint.Console.Program.start(ParseResults`1 arguments, ToolsPath toolsPath) in /home/runner/work/FSharpLint/FSharpLint/src/FSharpLint.Console/Program.fs:line 133

Expected behavior

Ability to successfully lint projects targeting latest .NET version.

Actual behavior

Not able to lint projects targeting latest .NET version.

Related information

❯ ~ dotnet --info
.NET SDK:
 Version:           9.0.101
 Commit:            eedb237549
 Workload version:  9.0.100-manifests.3068a692
 MSBuild version:   17.12.12+1cce77968

Runtime Environment:
 OS Name:     Mac OS X
 OS Version:  14.6
 OS Platform: Darwin
 RID:         osx-arm64
 Base Path:   /usr/local/share/dotnet/sdk/9.0.101/

.NET workloads installed:
There are no installed workloads to display.
Configured to use loose manifests when installing new manifests.

Host:
  Version:      9.0.0
  Architecture: arm64
  Commit:       9d5a6a9aa4

.NET SDKs installed:
  8.0.204 [/usr/local/share/dotnet/sdk]
  8.0.401 [/usr/local/share/dotnet/sdk]
  9.0.100 [/usr/local/share/dotnet/sdk]
  9.0.101 [/usr/local/share/dotnet/sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 8.0.4 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 8.0.8 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 9.0.0 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 8.0.4 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 8.0.8 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 9.0.0 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]

Other architectures found:
  None

Environment variables:
  Not set

global.json file:
  Not found

Learn more:
  https://aka.ms/dotnet/info

Download .NET:
  https://aka.ms/dotnet/download

[Malevrovich]

Had the same issue. This helped me #687 (comment)
Try to run lint with DOTNET_ROLL_FORWARD=latestMajor

[b-hodge]

@Malevrovich Thanks for your response. Running lint with DOTNET_ROLL_FORWARD=latestMajor fails for me in a different way:

❯ movableink/scratch/fsharplint-9.0 dotnet build src/Library/Library.fsproj
Restore complete (0.2s)
  Library succeeded (0.1s) → src/Library/bin/Debug/net9.0/Library.dll

Build succeeded in 0.7s

❯ movableink/scratch/fsharplint-9.0 set DOTNET_ROLL_FORWARD=latestMajor

❯ movableink/scratch/fsharplint-9.0 dotnet fsharplint lint src/Library/Library.fsproj
Lint failed to parse files. Failed with: Type check failed. You might want to build your solution/project first and try again.
Type check failed. You might want to build your solution/project first and try again.
Type check failed. You might want to build your solution/project first and try again.

Are you able to successfully lint a project targeting .NET 9? Does the minimal reproduction in my initial post work for you?