How to use C# 7.1 in omnisharp?

[NinoFloris]

Things like default literal are already supported by compilers but omnisharp doesn't pick up the LangVersion csproj attribute and so roslyn gives errors for these features.
Unless I'm missing something and there is another way this should be fixed.

[willl]

Hrm. I thought support was already added by #935? Which is part of release v1.23.1 and higher.

@NinoFloris Which version of omnisharp-roslyn have you got installed?

[NinoFloris]

Running omnisharp vscode 1.12.1, 1.12.0 states in the changelog it now supports c# 7.1.

I cannot find how to enable that support however

[david-driscoll]

use <LangVersion>latest</LangVersion> or <LangVersion>7.1</LangVersion> in your csproj. I'm actually not sure if latest does work off the top of my head.

[pnloyd]

For the record latest does work.

[NinoFloris]

If the property value was actually plumbed then yes, latest is a valid value and refers to the latest minor language version.

[vnextcoder]

Is there a LanguageVersion 7.3 support in Omnisharp/Rosyln with Visual Studio Code ?

Below VS code is fine with below 3 lines when I set LanguageVersion to 7.1, but VSCode doesn't recognise 7.3 and complains about tuple Comparison on 6th line ..

    int x=default;
    string y=default;
    bool z=default;
    var left = (1,5);
    var right = (1,5);
    Console.WriteLine(left==right);

The whole code works fine with "dotnet run" if I set Language Version using Visual Studio Community 15.7.3 but VSCode still keeps on complaining about Tuple Comparison .

Below is my CSPROJ

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

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp2.1</TargetFramework>
  </PropertyGroup>

  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|AnyCPU'">
    <LangVersion>7.3</LangVersion>
  </PropertyGroup>

  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">
    <LangVersion>7.3</LangVersion>
  </PropertyGroup>
  <PropertyGroup>
  <LangVersion>7.3</LangVersion>
  </PropertyGroup>

  
</Project>

[DustinCampbell]

Yes. However, this was just added and isn't in an official OmniSharp build yet. If you want to use C# 7.3 in VS Code you can set the following option in your VS Code settings:

{
  "omnisharp.path": "latest"
}