Every single error message is displayed twice.

Environment data

dotnet --info output:
.NET Command Line Tools (2.0.2)

Product Information:
Version: 2.0.2
Commit SHA-1 hash: a04b4bf512

Runtime Environment:
OS Name: arch
OS Version:
OS Platform: Linux
RID: linux-x64
Base Path: /opt/dotnet/sdk/2.0.2/

Microsoft .NET Core Shared Framework Host

Version : 2.0.0
Build : e8b8861ac7faf042c87a5c2f9f2d04c98b69f28d

VS Code version: 1.18.1
C# Extension version: 1.13.1

Steps to reproduce

Open any C# file.

Expected behavior

Only one error message will be shown per error.

Actual behavior

Every single error message is shown exactly twice: https://i.imgur.com/7WwUdn9.png. This does not only happen for semicolons, but for every C# error all the time.

Additional information

I have reinstalled both the C# extension and VS Code with no success. I have also noticed that right after opening VS Code, errors are only displayed once at first, but after around 2-3 seconds, every single error message will be shown twice from that point on. Furthermore, this happens only with the C# extension. When using linters for other languages, error messages are only displayed once.

[filipw]

This is a duplicate of #1830

@filipw Is there an ETA on the fix for this?

[DustinCampbell]

Since this is a duplicate of #1830, I'm going to go ahead and close this issue. Please continue any discussion over there.

[josmithua]

I'm still seeing this issue. Only difference between the two duplicated error lines is on the right of the problems pane:

...       (CS1061) [12, 93]
... csharp(CS1061) [12, 93]

Is it because I have the C# extension installed?

Version: 1.54.1
Commit: f30a9b73e8ffc278e71575118b6bf568f04587c8
Date: 2021-03-04T22:42:18.719Z (1 wk ago)
Electron: 11.3.0
Chrome: 87.0.4280.141
Node.js: 12.18.3
V8: 8.7.220.31-electron.0
OS: Darwin x64 20.3.0

EDIT: I disabled the C# extension and the second error went away, but I like it more than the first error (has a better error message, and is better at navigating and selecting the broken code). Is there a way I can disable the first error while keeping the second from the extension?

EDIT 2: I removed this line from my tasks: "problemMatcher": "$msCompile", and that stopped the first error from appearing (it was only appearing when running tasks).