Microsoft.VisualStudio.Web.CodeGeneration.Design causes package downgrade error NU1605 for Microsoft.NETCore.App

Microsoft.VisualStudio.Web.CodeGeneration.Design has Microsoft.NETCore.App listed in its nuspec dependencies. This causes issues when the .NET Core SDK picks an implicit reference to Microsoft.NETCore.App that is lower than what the .Design package depends on.

Repro: Create app with the 2.0.0 SDK. Add or upgrade Microsoft.VisualStudio.Web.CodeGeneration.Design to 2.0.1 Restore.

Result:

error NU1605: Detected package downgrade: Microsoft.NETCore.App from 2.0.3 to 2.0.0. Reference the package directly from the project to select a different version.
 WebApplication1 (>= 1.0.0) -> Microsoft.VisualStudio.Web.CodeGeneration.Design (>= 2.0.1) -> Microsoft.NETCore.App (>= 2.0.3)

Workarounds:

1. Upgrade Microsoft.NETCore.App (recommended)

<PropertyGroup>
  <RuntimeFrameworkVersion>2.0.3</RuntimeFrameworkVersion>
</PropertyGroup>

1. Suppress NU1605 (may hide other issues)

<PropertyGroup>
  <NoWarn>$(NoWarn);NU1605</NoWarn>
</PropertyGroup>

Recommendation: We should remove Microsoft.NETCore.App from the nuspec dependencies and rely on the project to determine the runtime version use to launch dotnet-aspnet-codegenerator-design.exe

[mnmr]

@natemcmaster It was indeed a PackageReference, thanks.

[natemcmaster]

@mmr is your reference to Microsoft.VisualStudio.Web.CodeGeneration.Tools a DotNetCliToolReference or a PackageReference? It should be the former.