Simple script referencing nuget package shows many errors

[ghord]

Issue Description

I'm trying to get omnisharp to work with nuget package, and I keep getting intellisense errors on every line of the script:

(Sorry for the polish language on the error, it's error: Predefined type 'System.Object' is not defined or imported.)

Some additional observations on this behavior:

1. If I don't load nuget package, the errors do not appear. I've tried to load different nuget package targetting .net5 and it didn't change anything.
2. Once those errors start appearing, removing '#r "nuget: ..."' does not help, even with reloading of omnisharp (Ctrl+Shift+P -> Omnisharp: Restart omnisharp). Only restart of vscode helps.
3. Just after reload of omnisharp, before I start to edit any code, intellisense hints on the methods appear correctly. Only changing any code causes errors to appear.
4. Running the code and even debugging works fine.

For me it looks like this could be connected to some roslyn analyzers?

Steps to Reproduce

1. Place following script in csx file:

#r "nuget:Newtonsoft.Json,12.0.3"

var z = 3;

var x = z.ToString();

var y = x + "asdf";

2. Use omnisharp.json file:

{
  "script": {
    
    "enableScriptNuGetReferences": true,
    "defaultTargetFramework": "net5.0"
  }
}

3. After reloading Omnisharp there are no errors/problems show
4. Type any character in editor window (space/etc)
5. Errors appear on every line

Expected Behavior

Editing works without any errors

Actual Behavior

Errors on every line

Logs

OmniSharp log

Details

Starting OmniSharp server at 20.11.2020, 15:42:49
Target: c:\Users\hordy\Documents\Hokey

OmniSharp server started.
Path: c:\Users\hordy.vscode\extensions\ms-dotnettools.csharp-1.23.6.omnisharp\1.37.3\OmniSharp.exe
PID: 9876

Starting OmniSharp on Windows 6.2.9200.0 (x64)
info: OmniSharp.Services.DotNetCliService
DotNetPath set to dotnet
info: OmniSharp.MSBuild.Discovery.MSBuildLocator
Located 3 MSBuild instance(s)
1: Visual Studio Community 2019 16.8.30608.117 - "C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\MSBuild\Current\Bin"
2: Visual Studio Community 2019 16.8.30717.126 - "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Current\Bin"
3: StandAlone 16.8.0 - "c:\Users\hordy.vscode\extensions\ms-dotnettools.csharp-1.23.6.omnisharp\1.37.3.msbuild\Current\Bin"
info: OmniSharp.MSBuild.Discovery.MSBuildLocator
Registered MSBuild instance: Visual Studio Community 2019 16.8.30717.126 - "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Current\Bin"
info: OmniSharp.Cake.CakeProjectSystem
Detecting Cake files in 'c:\Users\hordy\Documents\Hokey'.
info: OmniSharp.Cake.CakeProjectSystem
Could not find any Cake files
info: OmniSharp.MSBuild.ProjectSystem
No solution files found in 'c:\Users\hordy\Documents\Hokey'
info: OmniSharp.Script.ScriptProjectSystem
Detecting CSX files in 'c:\Users\hordy\Documents\Hokey'.
info: OmniSharp.Script.ScriptProjectSystem
Found 1 CSX files.
info: OmniSharp.Script.ScriptContextProvider
Searching for compilation dependencies with the fallback framework of 'net5.0'.
info: OmniSharp.Script.ScriptProjectSystem
Added CSX project 'c:\Users\hordy\Documents\Hokey\Test.csx' to the workspace.
info: OmniSharp.WorkspaceInitializer
Invoking Workspace Options Provider: OmniSharp.Roslyn.CSharp.Services.CSharpFormattingWorkspaceOptionsProvider, Order: 0
info: OmniSharp.WorkspaceInitializer
Invoking Workspace Options Provider: OmniSharp.Roslyn.CSharp.Services.Completion.CompletionOptionsProvider, Order: 0
info: OmniSharp.WorkspaceInitializer
Invoking Workspace Options Provider: OmniSharp.Roslyn.CSharp.Services.RenameWorkspaceOptionsProvider, Order: 100
info: OmniSharp.WorkspaceInitializer
Invoking Workspace Options Provider: OmniSharp.Roslyn.CSharp.Services.ImplementTypeWorkspaceOptionsProvider, Order: 110
info: OmniSharp.WorkspaceInitializer
Invoking Workspace Options Provider: OmniSharp.Roslyn.CSharp.Services.BlockStructureWorkspaceOptionsProvider, Order: 140
info: OmniSharp.WorkspaceInitializer
Configuration finished.
info: OmniSharp.Stdio.Host
Omnisharp server running using Stdio at location 'c:\Users\hordy\Documents\Hokey' on host 17176.

Environment information

VSCode version: 1.51.1
C# Extension: 1.23.6

Dotnet Information

Zestaw .NET SDK (odzwierciedlenie dowolnego pliku global.json): Version: 5.0.100 Commit: 5044b93829

�rodowisko uruchomieniowe:
OS Name: Windows
OS Version: 10.0.18363
OS Platform: Windows
RID: win10-x64
Base Path: C:\Program Files\dotnet\sdk\5.0.100\

Host (useful for support):
Version: 5.0.0
Commit: cf258a14b7

.NET SDKs installed:
1.0.0-preview2-003131 [C:\Program Files\dotnet\sdk]
1.0.0-preview4-004233 [C:\Program Files\dotnet\sdk]
1.0.0-rc4-004771 [C:\Program Files\dotnet\sdk]
1.0.0 [C:\Program Files\dotnet\sdk]
1.0.1 [C:\Program Files\dotnet\sdk]
1.0.4 [C:\Program Files\dotnet\sdk]
1.1.0 [C:\Program Files\dotnet\sdk]
2.0.0 [C:\Program Files\dotnet\sdk]
2.0.2 [C:\Program Files\dotnet\sdk]
2.1.2 [C:\Program Files\dotnet\sdk]
2.1.4 [C:\Program Files\dotnet\sdk]
2.1.100 [C:\Program Files\dotnet\sdk]
2.1.101 [C:\Program Files\dotnet\sdk]
2.1.104 [C:\Program Files\dotnet\sdk]
2.1.200-preview-007517 [C:\Program Files\dotnet\sdk]
2.1.200-preview-007576 [C:\Program Files\dotnet\sdk]
2.1.202 [C:\Program Files\dotnet\sdk]
2.1.400 [C:\Program Files\dotnet\sdk]
2.1.402 [C:\Program Files\dotnet\sdk]
2.1.500 [C:\Program Files\dotnet\sdk]
2.1.503 [C:\Program Files\dotnet\sdk]
2.1.600-preview-009426 [C:\Program Files\dotnet\sdk]
2.1.600-preview-009472 [C:\Program Files\dotnet\sdk]
2.1.600-preview-009497 [C:\Program Files\dotnet\sdk]
2.1.602 [C:\Program Files\dotnet\sdk]
2.1.700 [C:\Program Files\dotnet\sdk]
3.0.100-preview6-012264 [C:\Program Files\dotnet\sdk]
3.0.100 [C:\Program Files\dotnet\sdk]
5.0.100-rc.2.20479.15 [C:\Program Files\dotnet\sdk]
5.0.100 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.All 2.1.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.21 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.21 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.0.0-preview6.19307.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.0-rc.2.20475.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 1.0.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 1.0.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 1.0.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 1.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 1.1.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 1.1.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 1.1.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.0.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.0.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.0.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.21 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.0.0-preview6-27804-01 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.0-rc.2.20475.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.0.0-preview6-27804-01 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 3.1.7 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.0-rc.2.20475.6 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

To install additional .NET runtimes or SDKs:
https://aka.ms/dotnet-download

Visual Studio Code Extensions

Extension	Author	Version
cpptools	ms-vscode	1.1.2
csharp	ms-dotnettools	1.23.6
vscode-arduino	vsciot-vscode	0.3.3
vscode-autohotkey	slevesque	0.2.2
xml	DotJoshJohnson	2.5.1

[ghord]

I've also tried using #r 'path to nuget dll' and I'm still gettings the same errors

[filipw]

according to your log you are trying to use scripting with .NET 5.0, the support for that was only merged a week ago (#2012) and has not been released yet.

you may try to set "omnisharp.path":"latest" which will install the pre-release OmniSharp server to see if it helps.

[ghord]

Thank you, switching to latest fixed the issue.