[dotnet-sdk-10.0.100-rc.2.25474.116] BilibiliLiveRecordDownLoader build failed with error: Operator '.' cannot be applied to operand of type 'void'.

[Junjun-zhao]

Application Name: BilibiliLiveRecordDownLoader
OS： Windows 10 22H2
CPU: X64
.NET Build Number: dotnet-sdk-10.0.100-rc.2.25474.116

AppSource checking at: https://devdiv.visualstudio.com/DevDiv/_workitems/edit/2581961
Github Link: https://github.com/HMBSbige/BilibiliLiveRecordDownLoader

Verify Scenarios

Windows10 22h2 x64 + dotnet-sdk-9.0.305: Pass
Windows10 22h2 x64 + dotnet-sdk-10.0.100-preview.7.25380.108: Pass
Windows10 22h2 x64 + dotnet-sdk-10.0.100-rc.1.25451.107: Fail
Windows10 22h2 x64 + dotnet-sdk-10.0.100-rc.2.25474.116: Fail

Description:

We build the third-party app with dotnet-sdk-10.0.100-rc.2.25474.116, it failed with error: Operator '.' cannot be applied to operand of type 'void'.

Repro steps:

The machine needs to install dotnet-sdk-10.0.100-rc.2.25474.116

1. Run command: "dotnet build" in \BilibiliLiveRecordDownLoader\BilibiliLiveRecordDownLoader.BilibiliApi.

Expected Result:

Build successfully.

Actual Result:
Build failed with error:
error CS0023: dotnet --infoOperator '.' cannot be applied to operand of type 'void'

DotNet Info:

.NET SDK:
 Version:           10.0.100-rc.2.25474.116
 Commit:            54303ce0f4
 Workload version:  10.0.100-manifests.62cb6acc
 MSBuild version:   18.0.0-preview-25474-116+54303ce0f

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.19045
 OS Platform: Windows
 RID:         win-x64
 Base Path:   C:\Program Files\dotnet\sdk\10.0.100-rc.2.25474.116\

Host:
  Version:      10.0.0-rc.2.25474.116
  Architecture: x64
  Commit:       54303ce0f4

.NET SDKs installed:
  10.0.100-rc.2.25474.116 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 10.0.0-rc.2.25474.116 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 10.0.0-rc.2.25474.116 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 10.0.0-rc.2.25474.116 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

@dotnet-actwx-bot @dotnet/compat

[jjonescz]

Looks like this breaking change: https://github.com/dotnet/roslyn/blob/main/docs/compilers/CSharp/Compiler%20Breaking%20Changes%20-%20DotNet%2010.md#enumerablereverse

The app uses <LangVersion>latest</LangVersion> (with .net 10 rc1 that corresponds to C# 14) with <TargetFramework>net9.0</TargetFramework> which is an unsupported configuration. Either it should use C# 13 with net9.0 or C# 14 with TargetFramework net10.0. (Or there are other possible workarounds listed in the linked doc.)

[CancanTang]

Thanks @jjonescz , I tried switching the project to net9.0 with C# 13, and it works fine under that configuration.

[marcpopMSFT]

Closing per comment from jjonsescz above that this is intentional.