visual-studio-mac

Global using packages in Visual studio for mac 2019

I have project on .net 6.0.106, and when i build it, it gives me error:

BuildingPassport/HousePassport.Domain/obj/Debug/net6.0/HousePassport.Domain.GlobalUsings.g.cs(1,1): Error CS0116: A namespace cannot directly contain members such as fields or methods (CS0116) (HousePassport.Domain)

and when i go to this file, it gives me this:

// <auto-generated/>
global using global::System;
global using global::System.Collections.Generic;
global using global::System.IO;
global using global::System.Linq;
global using global::System.Net.Http;
global using global::System.Threading;
global using global::System.Threading.Tasks;

One of my collegue said, that on windows, it has on project options have tab General->Global Usings as in the image: enter image description here

But i cannot found it in VS for mac, what's my problem?

I have Visual Studio for Mac Community(v8.10.25(build 2))

Here's details:

Visual Studio Community 2019 for Mac
Version 8.10.25 (build 2)
Installation UUID: 78cd4d01-f097-4a1a-9faf-b2ee9edbfae3
    GTK+ 2.24.23 (Raleigh theme)
    Xamarin.Mac 6.18.0.23 (d16-6 / 088c73638)

    Package version: 612000182

Mono Framework MDK
Runtime:
    Mono 6.12.0.182 (2020-02/6051b710727) (64-bit)
    Package version: 612000182

Roslyn (Language Service)
3.10.0-4.21269.26+029847714208ebe49668667c60ea5b0a294e0fcb

NuGet
Version: 5.9.0.7134

.NET SDK (x64)
SDK: /usr/local/share/dotnet/x64/sdk/6.0.106/Sdks
SDK Versions:
    6.0.106
    5.0.408
    3.1.420
MSBuild SDKs: /Applications/Visual Studio.app/Contents/Resources/lib/monodevelop/bin/MSBuild/Current/bin/Sdks

.NET Core Runtime
Runtime: /usr/local/share/dotnet/x64/dotnet
Runtime Versions:
    6.0.6
    5.0.17
    3.1.26
Operating System

Mac OS X 13.0.1
Darwin 22.1.0 Darwin Kernel Version 22.1.0
    Sun Oct  9 20:14:30 PDT 2022
    root:xnu-8792.41.9~2/RELEASE_ARM64_T8103 x86_64

here's additional .csproj file:

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

  <PropertyGroup>
    <TargetFramework>net6.0</TargetFramework>
    <Nullable>enable</Nullable>
    <ImplicitUsings>enable</ImplicitUsings>
  </PropertyGroup>

Error: enter image description here

Solution

  • The underlying problem is that global usings requires C# 10.0 and Visual Studio for Mac 8.10 (2019) uses Mono to build .NET SDK style projects, and Mono does not support C# 10.0.

    > which csc
/Library/Frameworks/Mono.framework/Versions/Current/Commands/csc

    > csc "/langversion:?"
Supported language versions:
default
1
2
3
4
5
6
7.0
7.1
7.2
7.3
8.0
9.0 (default)
latestmajor
preview
latest

    Your options are:

    1. Disable global usings.
    2. Try to use a later Roslyn by using the Microsoft.Net.Compilers.Toolset NuGet package (see below).
    3. Use Visual Studio for Mac 2022.

    This PackageReference allows C# 10.0 code to be compiled.

      <ItemGroup>
    <PackageReference Include="Microsoft.Net.Compilers.Toolset" Version="4.0.1" />
  </ItemGroup>