Cannot resolve symbol 'notnull'

Question

I'm using a netcoreapp3.0 with Visual Studio 16.3.1 and have a simple class. The ReSharper 2019.2.20190828.152259 is also installed.

Here are the contents of the csproj:

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

  <PropertyGroup>
    <TargetFramework>netcoreapp3.0</TargetFramework>
    <LangVersion>8.0</LangVersion>
    <Nullable>enable</Nullable>
  </PropertyGroup>

</Project>

I tried removing the bin & obj folders, restarted Visual Studio, restarted Windows, but nothing helped.

Update: The problem comes from the ReSharper, but the latest update does not fix this. Is it perhaps a configuration problem?

Answer 1

I contacted the support of JetBrains and they informed me that it is a missing feature, coming in the 2019.3 version.

Here is the issue:

https://youtrack.jetbrains.com/issue/RSRP-475665