Issue with missing namespaces and indirect dependencies

[Chanka0]

Problem

Recently setup cookiecutter to automate mod creation. Tried a test mod, and this was the error log I had.

1>B:\Dev\VS 2019\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(2106,5): warning MSB3258: The primary reference "Assembly-CSharp" could not be resolved because it has an indirect dependency on the .NET Framework assembly "mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" which has a higher version "4.0.0.0" than the version "2.0.0.0" in the current target framework. 1>B:\Dev\VS 2019\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(2106,5): warning MSB3258: The primary reference "Assembly-CSharp" could not be resolved because it has an indirect dependency on the .NET Framework assembly "System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" which has a higher version "4.0.0.0" than the version "2.0.0.0" in the current target framework. 1>B:\Dev\VS 2019\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(2106,5): warning MSB3258: The primary reference "Assembly-CSharp" could not be resolved because it has an indirect dependency on the .NET Framework assembly "System.Core, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" which has a higher version "4.0.0.0" than the version "3.5.0.0" in the current target framework. 1>B:\Dev\VS 2019\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(2106,5): warning MSB3258: The primary reference "Assembly-CSharp" could not be resolved because it has an indirect dependency on the .NET Framework assembly "System.Xml, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" which has a higher version "4.0.0.0" than the version "2.0.0.0" in the current target framework. 1>B:\Dev\VS 2019\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(2106,5): warning MSB3258: The primary reference "Assembly-CSharp" could not be resolved because it has an indirect dependency on the .NET Framework assembly "System.Xml.Linq, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" which has a higher version "4.0.0.0" than the version "3.5.0.0" in the current target framework. 1>B:\Dev\VS 2019\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(2106,5): warning MSB3258: The primary reference "Assembly-CSharp" could not be resolved because it has an indirect dependency on the .NET Framework assembly "System.Configuration, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" which has a higher version "4.0.0.0" than the version "2.0.0.0" in the current target framework. 1>B:\Dev\VS 2019\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(2106,5): warning MSB3258: The primary reference "Assembly-CSharp" could not be resolved because it has an indirect dependency on the .NET Framework assembly "System.Runtime.Serialization, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" which has a higher version "4.0.0.0" than the version "3.0.0.0" in the current target framework. 1>B:\Dev\VS 2019\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(2106,5): warning MSB3258: The primary reference "Assembly-CSharp" could not be resolved because it has an indirect dependency on the .NET Framework assembly "System.Security, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" which has a higher version "4.0.0.0" than the version "2.0.0.0" in the current target framework. 1>B:\Steam\steamapps\common\RimWorld\Mods\Test Mod\Source\Test_Mod.cs(2,7,2,15): error CS0246: The type or namespace name 'RimWorld' could not be found (are you missing a using directive or an assembly reference?) 1>B:\Steam\steamapps\common\RimWorld\Mods\Test Mod\Source\Test_Mod.cs(3,7,3,12): error CS0246: The type or namespace name 'Verse' could not be found (are you missing a using directive or an assembly reference?) 1>B:\Steam\steamapps\common\RimWorld\Mods\Test Mod\Source\Test_Mod.cs(5,7,5,12): error CS0246: The type or namespace name 'Verse' could not be found (are you missing a using directive or an assembly reference?)

I tried re-adding UnityEngine.dll and Assembly-CSharp.dll but continued to have this error.

[Chanka0]

Fixed. Was using .Net 3.5 Framework, needed .Net 4 Framework instead