Warning/errors being shown twice

[vieirandre]

Environment data

dotnet --info output:

Product Information:
Version:            2.1.4
Commit SHA-1 hash:  5e8add2190

Runtime Environment:
OS Name:     Windows
OS Version:  10.0.16299
OS Platform: Windows
RID:         win10-x64
Base Path:   C:\Program Files\dotnet\sdk\2.1.4\

Microsoft .NET Core Shared Framework Host

Version  : 2.0.5
Build    : 17373eb129b3b05aa18ece963f8795d65ef8ea54

VS Code version:

1.19.2 (x64)

C# Extension version:

1.13.1

Steps to reproduce

1. Create a Console Application project with dotnet new console
2. Declare [and optionally assign] a value to any variable. For instance, int x = 1;
3. Do not use it anywhere in the code.
4. Hover the mouse over it.

Obs.: sometimes you need to hover twice to get the fault behavior, or let the pointer over the variable for a bit.

Expected behavior

A warning stating:

The variable 'x' is assigned but its value is never used [namespace]
int x

Actual behavior

The warning appears twice:

The variable 'x' is assigned but its value is never used [namespace]
The variable 'x' is assigned but its value is never used [namespace]
int x

[vieirandre]

I changed the title because I noticed that this duplication behavior happens with any warnings/errors.

[imba-tjd]

@DustinCampbell Fine. I think this is a duplicate of #1830

[DustinCampbell]

Thanks @imba-tjd. Agreed!