vscode-csharp: No red wavy underlines (squiggly lines) for error generating/gibberish code.

Environment data

dotnet --info output:

VS Code version: 1.14.2 C# Extension version: 1.11.0

Steps to reproduce

Open C# file in Unity3D with VS Code

Expected behavior

Errors are detected and show red squiggles/wavy underline

Actual behavior

Gibberish code is interpreted as normal and does not notify you of an error.

Omnisharp Log Output

Starting OmniSharp server at 2017-08-06, 8:39:01 PM
    Target: c:\Users\Antoine\Documents\Unity Projects\The Deep\The Deep-csharp.sln

OmniSharp server started
    Path: C:\Users\Antoine\.vscode\extensions\ms-vscode.csharp-1.11.0\bin\omnisharp\OmniSharp.exe
    PID: 197284

OmniSharp: -s c:\Users\Antoine\Documents\Unity Projects\The Deep\The Deep-csharp.sln --hostPID 194180 --stdio DotNet:enablePackageRestore=false --encoding utf-8 --loglevel information formattingOptions:useTabs=false formattingOptions:tabSize=4 formattingOptions:indentationSize=4
[info]: OmniSharp.Startup
        Omnisharp server running using Stdio at location 'c:\Users\Antoine\Documents\Unity Projects\The Deep' on host 194180.
[info]: OmniSharp.DotNet.DotNetProjectSystem
        Initializing in c:\Users\Antoine\Documents\Unity Projects\The Deep
[info]: OmniSharp.DotNet.DotNetProjectSystem
        Auto package restore: False
[info]: OmniSharp.DotNet.DotNetProjectSystem
        Update workspace context
[info]: OmniSharp.DotNet.DotNetProjectSystem
        Resolving projects references
[info]: OmniSharp.MSBuild.MSBuildProjectSystem
        MSBuild will use local Visual Studio installation.
[info]: OmniSharp.MSBuild.MSBuildProjectSystem
        Detecting projects in 'c:\Users\Antoine\Documents\Unity Projects\The Deep\The Deep-csharp.sln'.
[fail]: OmniSharp.Startup
        The project system 'OmniSharp.MSBuild.MSBuildProjectSystem' threw exception during initialization.
System.ArgumentException: "parenthesizedName" must be a non-null and non-empty string.
   à OmniSharp.MSBuild.SolutionParsing.SectionBlock..ctor(String type, String parenthesizedName, String value, ReadOnlyCollection`1 keyValuePairs)
   à OmniSharp.MSBuild.SolutionParsing.SectionBlock.Parse(TextReader reader)
   à OmniSharp.MSBuild.SolutionParsing.SolutionFile.ParseGlobal(TextReader reader)
   à OmniSharp.MSBuild.SolutionParsing.SolutionFile.Parse(TextReader reader)
   à OmniSharp.MSBuild.SolutionParsing.SolutionFile.Parse(String solutionFileName)
   à OmniSharp.MSBuild.MSBuildProjectSystem.GetProjectPathsFromSolution(String solutionFilePath)
   à OmniSharp.MSBuild.MSBuildProjectSystem.Initalize(IConfiguration configuration)
   à OmniSharp.Startup.InitializeWorkspace(OmniSharpWorkspace workspace, CompositionHost compositionHost, IConfiguration configuration, ILogger logger, OmniSharpOptions options)
[info]: OmniSharp.Script.ScriptProjectSystem
        Detecting CSX files in 'c:\Users\Antoine\Documents\Unity Projects\The Deep'.
[info]: OmniSharp.Script.ScriptProjectSystem
        Could not find any CSX files
[info]: OmniSharp.Startup
        Invoking Workspace Options Provider: OmniSharp.Roslyn.CSharp.Services.CSharpWorkspaceOptionsProvider
[info]: OmniSharp.Startup
        Configuration finished.

Extensions used

I’ve already tried reinstalling VS Code, the C# extension and every other extension by itself after. I cannot get errors to be reported and I’ve googled for hours to no avail. Hopefully I’m posting this in the right place.