CS9270 'InterceptsLocationAttribute(string, int, int)' is not supported when using Microsoft.Extensions.Configuration.Binder 8.0.x

[eerhardt]

Version Used: C# Tools 4.13.0-3.24620.4+98ea496177bc8e607dbf454abd6b5a5e4678aed2

Steps to Reproduce:

1. Build https://github.com/dotnet/aspire/tree/main/src/Components/Aspire.Azure.AI.OpenAI using the latest Roslyn build

• or -

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>net9.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
    <EnableConfigurationBindingGenerator>true</EnableConfigurationBindingGenerator>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.Extensions.Configuration.Binder" Version="8.0.2" />
  </ItemGroup>
  
</Project>

using Microsoft.Extensions.Configuration;

public class Class1
{
    public static void Bind(IConfiguration config)
    {
        var option = new Options();
        config.Bind(option);
    }
}

public class Options
{
    public string? Name { get; set; }
}

Diagnostic Id:

CS9270 'InterceptsLocationAttribute(string, int, int)' is not supported.

Expected Behavior:

The current Long-Term Supported version of Microsoft.Extensions.Configuration.Binder should be able to be used without warnings/errors.

Actual Behavior:

You get a warning (turned into an error in repos with warning-as-error):

Warning (active)	CS9270	'InterceptsLocationAttribute(string, int, int)' is not supported. Move to 'InterceptableLocation'-based generation of these attributes instead. (https://github.com/dotnet/roslyn/issues/72133)	ConsoleApp3	D:\source\ConsoleApp3\ConsoleApp3\obj\Debug\net9.0\Microsoft.Extensions.Configuration.Binder.SourceGeneration\Microsoft.Extensions.Configuration.Binder.SourceGeneration.ConfigurationBindingGenerator\BindingExtensions.g.cs	38		

cc @ericstj @tarekgh @RikkiGibson

[eerhardt]

Seems to have been caused by Mark interceptors feature as stable and deprecate file path based attributes (dotnet/roslyn#76312).

[tarekgh]

CC @steveharter

[eerhardt]

Note - this issue could be moved to dotnet/runtime, if the plan is to update and ship a Microsoft.Extensions.Configuration.Binder v8.0.x version that doesn't cause the warning. I wasn't sure which repo to report the issue in, so I picked the repo that made the latest change to cause the problem.

[eerhardt]

Note the same warning is emitted for 8.0 web api projects.

1. Create new project -> ASP.NET Core Web Api (native AOT)
2. Select net8.0 Long-Term Support
3. Create
4. Build

Severity	Code	Description	Project	File	Line	Suppression State	Details
Warning (active)	CS9270	'InterceptsLocationAttribute(string, int, int)' is not supported. Move to 'InterceptableLocation'-based generation of these attributes instead. (https://github.com/dotnet/roslyn/issues/72133)	WebApplication3	D:\source\WebApplication3\WebApplication3\obj\Debug\net8.0\Microsoft.AspNetCore.Http.RequestDelegateGenerator\Microsoft.AspNetCore.Http.RequestDelegateGenerator.RequestDelegateGenerator\GeneratedRouteBuilderExtensions.g.cs	61		
Warning (active)	CS9270	'InterceptsLocationAttribute(string, int, int)' is not supported. Move to 'InterceptableLocation'-based generation of these attributes instead. (https://github.com/dotnet/roslyn/issues/72133)	WebApplication3	D:\source\WebApplication3\WebApplication3\obj\Debug\net8.0\Microsoft.AspNetCore.Http.RequestDelegateGenerator\Microsoft.AspNetCore.Http.RequestDelegateGenerator.RequestDelegateGenerator\GeneratedRouteBuilderExtensions.g.cs	143		

Opened: dotnet/aspnetcore#59735.

cc @captainsafia @DamianEdwards @mikekistler

[tarekgh]

We need to figure out the right fix and then we should service 8.0 if the fix comes from the runtime.

CC @RikkiGibson

[CyrusNajmabadi]

This doesn't seem like a roslyn issue. the InterceptsLocationAttribute(string, int, int) was part of the experimental feature, which has since been removed in favor of the new checksum-based attribute based on the file contents.

[tarekgh]

@CyrusNajmabadi Is there any published documentation for users who were using this feature, along with guidelines for transitioning to the checksum-based attribute? I know we (.NET Libraries) implemented this in version 9.0, but I’m checking if it's documented somewhere. I've noticed some user blogs still referencing the deprecated version.

[tarekgh]

Anyone has permission transferring issues to runtime repo can help moving it there.

[CyrusNajmabadi]

You can use CSharpSemanticModel.GetInterceptableLocation(invocationNode) to get an object that has the information needed to properly intercept an invocation. When generating code, you can then use iLoc.GetInterceptsLocationAttributeSyntax() to convert that to a string to emit into the generated code.

[CyrusNajmabadi]

Anyone has permission transferring issues to runtime repo can help moving it there.

Done :)

[dotnet-policy-service]

Tagging subscribers to this area: @dotnet/area-extensions-configuration
See info in area-owners.md if you want to be subscribed.

[eerhardt]

This doesn't seem like a roslyn issue.

Should we hold off on enabling this compiler warning until all supported usages (ConfigurationBinder and ASP.NET Minimal APIs v8) have moved off of it?

[tarekgh]

You can use CSharpSemanticModel.GetInterceptableLocation(invocationNode) to get an object that has the information needed to properly intercept an invocation. When generating code, you can then use iLoc.GetInterceptsLocationAttributeSyntax() to convert that to a string to emit into the generated code.

That is what we do in 9.0:
https://github.com/dotnet/runtime/blob/27fd292671ba8208b881e9f1fd79eb0d8b94f471/src/libraries/Microsoft.Extensions.Configuration.Binder/gen/ConfigurationBindingGenerator.cs#L86
https://github.com/dotnet/runtime/blob/27fd292671ba8208b881e9f1fd79eb0d8b94f471/src/libraries/Microsoft.Extensions.Configuration.Binder/gen/Specs/InterceptorInfo.cs#L202

[jaredpar]

@RikkiGibson for doc and expected migration plan discussion

[RikkiGibson]

It was not our goal to make generator authors service the .NET 8 versions of their generators to start using InterceptableLocation. The goal was just to get people moved to the new way for .NET 9 and up. Our plan is to leave in support for the "old way" in the SDK, for as long as .NET 8 is supported. At the time .NET 8 goes out of support, we will fully remove the support for the "old way" from the newest SDK.

I think the resolution here should be to adjust the compiler so that warning InterceptsLocationAttribute(string, int, int) is not supported is only reported when targeting .NET 9 or later.

[tarekgh]

@RikkiGibson Should this issue be moved back to the Roslyn repository then?