Incorrect SYSLIB1102 error

[JamesNK]

Description

I updated grpc/grpc-dotnet to use .NET 8 SDK. A new error showed up in a project with <PublishTrimmed>true</PublishTrimmed>: SYSLIB1102

The description at https://learn.microsoft.com/en-us/dotnet/fundamentals/syslib-diagnostics/syslib1100-1118 says C# 11 or later is required. I verified my app is using C# 11:

<Target Name="WriteVersion" BeforeTargets="BeforeCompile">
  <Message Importance="High" Text="Version: $(LangVersion)" />
</Target>

Build started at 11:38 am...
1>------ Build started: Project: LinkerTestsWebsite, Configuration: Debug Any CPU ------
1>Version: 11.0
1>CSC(1,1,1,1): error SYSLIB1102: (https://learn.microsoft.com/dotnet/fundamentals/syslib-diagnostics/syslib1102)
1>Done building project "LinkerTestsWebsite.csproj" -- FAILED.
========== Build: 0 succeeded, 1 failed, 3 up-to-date, 0 skipped ==========
========== Build completed at 11:38 am and took 00.520 seconds ==========

The problem disappeared after I changed <LangVersion> to 12.0.

Reproduction Steps

See grpc/grpc-dotnet#2321

Change the version back to 11.0 to see the error.

Expected behavior

Either works with C# 11, or the warning correctly says C# 12 is required.

Actual behavior

Breaks with C# 11, and a warning says C# 11 or later is required.

Regression?

I think this regressed between .NET 8 RC1 and .NET 8 RTM (although I might not have been using the final version of RC1. It definitely worked during .NET 8 previews)

Known Workarounds

No response

Configuration

No response

Other information

No response

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Issue Details

---

Description

I updated grpc/grpc-dotnet to use .NET 8 SDK. A new error showed up in a project with <PublishTrimmed>true</PublishTrimmed>: SYSLIB1102

The description at https://learn.microsoft.com/en-us/dotnet/fundamentals/syslib-diagnostics/syslib1100-1118 says C# 11 or later is required. I verified my app is using C# 11:

<Target Name="WriteVersion" BeforeTargets="BeforeCompile">
  <Message Importance="High" Text="Version: $(LangVersion)" />
</Target>

Build started at 11:38 am...
1>------ Build started: Project: LinkerTestsWebsite, Configuration: Debug Any CPU ------
1>Version: 11.0
1>CSC(1,1,1,1): error SYSLIB1102: (https://learn.microsoft.com/dotnet/fundamentals/syslib-diagnostics/syslib1102)
1>Done building project "LinkerTestsWebsite.csproj" -- FAILED.
========== Build: 0 succeeded, 1 failed, 3 up-to-date, 0 skipped ==========
========== Build completed at 11:38 am and took 00.520 seconds ==========

The problem disappeared after I changed <LangVersion> to 12.0.

Reproduction Steps

See grpc/grpc-dotnet#2321

Change the version back to 11.0 to see the error.

Expected behavior

Either works with C# 11, or the warning correctly says C# 12 is required.

Actual behavior

Breaks with C# 11, and a warning says C# 11 or later is required.

Regression?

I think this regressed between .NET 8 RC1 and .NET 8 RTM (although I might not have been using the final version of RC1. It definitely worked during .NET 8 previews)

Known Workarounds

No response

Configuration

No response

Other information

No response

Author:	JamesNK
Assignees:	-
Labels:	untriaged, area-Extensions-Configuration, needs-area-label
Milestone:	-

[tarekgh]

The error message is wrong. it should specify 12 not 11. The source gen is using the compiler interceptors feature which is introduced in v12.

[JamesNK]

If you look at the screenshot and build output, you’ll also see there is no error message, just the link. I think that should be fixed as well.

[tarekgh]

If you look at the screenshot and build output, you’ll also see there is no error message, just the link. I think that should be fixed as well.

That is interesting. We have tests to check the diag

runtime/src/libraries/Microsoft.Extensions.Configuration.Binder/tests/SourceGenerationTests/GeneratorTests.cs

Line 30 in 45978bd

ConfigBindingGenRunResult result = await RunGeneratorAndUpdateCompilation(BindCallSampleCode, langVersion: langVersion);

. Do you see this happen for only this generator and this message? or does it happen with other generators?

You may try the code like

runtime/src/libraries/Microsoft.Extensions.Configuration.Binder/tests/SourceGenerationTests/GeneratorTests.cs

Line 42 in 45978bd

string source = """

and look what you get for other diags. I'll try to look too when I get a chance.