error CS8773: "Feature 'global using directive' is not available in C# 9.0" after downgrade from net6.0 to net5.0

Question

I have a project that was initially created for .NET 6 but then I needed to downgrade it to .NET 5. I changed Target framework in Project Properties and tried to compile. As a result I received a bunch of the errors:

GlobalUsings.g.cs(2,1,2,29): error CS8773: Feature 'global using directive' is not available in C# 9.0. Please use language version 10.0 or greater.

File GlobalUsings.g.cs is created automatically and it reappears every time after compilation.

score 212 · Accepted Answer · answered Jan 15 '22 at 14:48

212

Finally I found that the reason is an extra property ImplicitUsings in the project file that is not supported by .net 5.0.

  <PropertyGroup>
    <TargetFramework>net5.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>

I needed to remove ImplicitUsings from the file.

answered Jan 15 '22 at 14:48

Yuriy Gavrishov

4,341
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3

it worked..thanks...I changed my framework back to **net6.0** based on your diagnosis – gdogra Feb 19 '22 at 11:14
When i did this then my project broke> does one then need to go and add the using directives back into each program? – Zapnologica May 02 '22 at 04:45
1

Yes @Zapnologica you need to add the using directives back. – qnaninf May 04 '22 at 15:02
3

Weirdly, I also got this Error using **.Net 6** and removing `ImplicitUsings` fixed it as well. – Tigerware Jul 17 '22 at 17:15

score 19 · Answer 2 · answered Jun 09 '22 at 07:50

19

remove <ImplicitUsings>enable</ImplicitUsings> in the csproj project file, then can build success

find this solution from here

answered Jun 09 '22 at 07:50

lily

191
1
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score 11 · Answer 3 · answered Aug 26 '22 at 13:21

11

Remove the tag indeed work.
But just change the value of it did the trick as well!

<ImplicitUsings>disable</ImplicitUsings>

answered Aug 26 '22 at 13:21

Thiago Timm

181
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score 7 · Answer 4 · answered Jul 22 '22 at 08:21

7

To get rid of this error which is caused by downgrading below net6.0.

Remove the following items from the .csproj file:

<ImplicitUsings>
<Using Include="..." />

answered Jul 22 '22 at 08:21

Mehrdad

1,523
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score 0 · Answer 5 · answered Oct 06 '22 at 04:45

If you don't want to remove the ImplicitUsings or made changes to the project file. You can tell the build cli to disable it during build process by

dotnet build --configuration "Release" --framework "net5.0" /p:ImplicitUsings=false /p:PublishReadyToRun=false

error CS8773: "Feature 'global using directive' is not available in C# 9.0" after downgrade from net6.0 to net5.0

5 Answers5