Unable to compile C# 8 using .NET Core 3, Preview 4

Question

I am currently using .NET Core 3, Preview 4 , and Visual Studio 2019, Version 16.0.2 .

Here are the contents of my .csproj file for my .NET Core project:

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

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp3.0</TargetFramework>
    <LangVersion>8.0</LangVersion>
  </PropertyGroup>

</Project>

As an experiment, I copied some code taken from this page into my project:

public static string RockPaperScissors(string first, string second)
=> (first, second) switch
{
    ("rock", "paper") => "rock is covered by paper. Paper wins.",
    ("rock", "scissors") => "rock breaks scissors. Rock wins.",
    ("paper", "rock") => "paper covers rock. Paper wins.",
    ("paper", "scissors") => "paper is cut by scissors. Scissors wins.",
    ("scissors", "rock") => "scissors is broken by rock. Rock wins.",
    ("scissors", "paper") => "scissors cuts paper. Scissors wins.",
    (_, _) => "tie"
};

However, it won't compile:

As you can see, the compiler displays the error message "Unexpected token".

What should I do to be able to use C# 8 language features in my .NET Core project?

Answer 1

我禁用了ReSharper，问题就消失了。