FindReferencesAsync Interface Bug - Issue 34568.linq

<Query Kind="Program">
  <NuGetReference>Microsoft.Build</NuGetReference>
  <NuGetReference>Microsoft.Build.Framework</NuGetReference>
  <NuGetReference>Microsoft.Build.Tasks.Core</NuGetReference>
  <NuGetReference>Microsoft.Build.Utilities.Core</NuGetReference>
  <NuGetReference>Microsoft.CodeAnalysis.CSharp</NuGetReference>
  <NuGetReference>Microsoft.CodeAnalysis.CSharp.Workspaces</NuGetReference>
  <NuGetReference>Microsoft.CodeAnalysis.Workspaces.MSBuild</NuGetReference>
  <NuGetReference>NuGet.Build.Tasks</NuGetReference>
  <NuGetReference>System.ValueTuple</NuGetReference>
  <Namespace>Microsoft.CodeAnalysis</Namespace>
  <Namespace>Microsoft.CodeAnalysis.CSharp.Syntax</Namespace>
  <Namespace>Microsoft.CodeAnalysis.FindSymbols</Namespace>
  <Namespace>Microsoft.CodeAnalysis.MSBuild</Namespace>
  <Namespace>System.Threading.Tasks</Namespace>
  <Namespace>Microsoft.CodeAnalysis.Options</Namespace>
  <Namespace>Microsoft.CodeAnalysis.CSharp</Namespace>
</Query>

void Main()
{
	var sln = CreateTestSolution();

	var prj = sln.Projects.First();
	var comp = prj.GetCompilationAsync().Result;

	var idriveable = comp.GetTypeByMetadataName("IDriveable");
	var idriveable_drive = idriveable.GetMembers("Drive").Single();
	var motorcycle = comp.GetTypeByMetadataName("Motorcycle");
	var motorcycle_drive = motorcycle.GetMembers("Drive").Single();

	SymbolFinder.FindReferencesAsync(motorcycle_drive, sln).Result.Dump("FindReferencesAsync for " + motorcycle_drive);
	SymbolFinder.FindCallersAsync(motorcycle_drive, sln).Result.Dump("FindCallersAsync for " + motorcycle_drive);

	SymbolFinder.FindReferencesAsync(idriveable_drive, sln).Result.Dump("FindReferencesAsync for " + idriveable_drive);
	SymbolFinder.FindCallersAsync(idriveable_drive, sln).Result.Dump("FindCallersAsync for " + idriveable_drive);

}

Solution CreateTestSolution()
{
	var projname = Util.CurrentQuery.Name;
	var projid = ProjectId.CreateNewId(projname);
	var ws = new AdhocWorkspace();
	AppDomain.CurrentDomain.GetAssemblies().Where(s => s.FullName.StartsWith("Microsoft")).Select(s => s.ToString()).Dump("Roslyn Version");
	var sln = ws.CurrentSolution
		.AddProject(projid, projname, projname, LanguageNames.CSharp)
		.AddMetadataReference(projid, MetadataReference.CreateFromFile(typeof(object).Assembly.Location))
		.AddDocument(DocumentId.CreateNewId(projid, "main.cs"),
					 "main.cs",
@"using System;

public interface IDriveable { void Drive(); }
public class Vehicle : IDriveable { public virtual void Drive() {} }
public class Motorcycle : Vehicle, IDriveable
{
	public override void Drive() {} 
	void IDriveable.Drive() { }
}
public class Tests
{
	public static void TestMotorcycle()
	{
		var m = new Motorcycle();
		m.Drive();
	}
	public static void TestDriveable(IDriveable d)
	{
		d.Drive();
	}
}
")
		;
	if (!ws.TryApplyChanges(sln)) throw new Exception("Cannot apply changes");
	
	return sln;
}