F# Intellisense, Code Navigation and Highlighting is not working

[vsfeedback]

Open https://github.com/fsharp/FAKE/blob/master/src/Fake-netcore.sln wait until it has loaded
Open Fake.Runtime/FakeRuntime.fs
No intellisense, code help, and only basic highlighting

Build works

This issue has been moved from https://developercommunity.visualstudio.com/content/problem/190803/f-intellisense-code-navigation-and-highlighting-is.html
VSTS ticketId: 559738
These are the original issue comments:
(no comments)
These are the original issue solutions:
(no solutions)

[cartermp]

cc @matthid

Since this is a public solution it'll be easier to just look at directly here. If we really need to, we can go back into the VSTS bug and grab the dump file.

[matthid]

Yes I thought the dumps might help just in case it doesn't reproduce for others :)

[cartermp]

@Pilchie I noticed this when opening up the solution in 15.6 Preview 3:

Log:

=====================
2/1/2018 1:38:45 PM
Recoverable
System.InvalidOperationException: Build target stack was corrupted and contain other unfinished targets. Expect: '_GetProjectReferenceTargetFrameworkProperties', Actual: 'ResolveProjectReferences'.
   at Microsoft.VisualStudio.Telemetry.WindowsErrorReporting.WatsonReport.GetClrWatsonExceptionInfo(Exception exceptionObject)
===================
2/1/2018 1:38:50 PM
Recoverable
System.InvalidOperationException: Build target stack was corrupted and contain other unfinished targets. Expect: 'DispatchToInnerBuilds', Actual: '_GetProjectReferenceTargetFrameworkProperties'.
   at Microsoft.VisualStudio.Telemetry.WindowsErrorReporting.WatsonReport.GetClrWatsonExceptionInfo(Exception exceptionObject)
===================
2/1/2018 1:39:08 PM
Recoverable
System.InvalidOperationException: Build target stack was corrupted and contain other unfinished targets. Expect: 'ResolveProjectReferences', Actual: 'CoreCompile'.
   at Microsoft.VisualStudio.Telemetry.WindowsErrorReporting.WatsonReport.GetClrWatsonExceptionInfo(Exception exceptionObject)
===================
2/1/2018 1:39:11 PM
Recoverable
System.InvalidOperationException: Build target stack was corrupted and contain other unfinished targets. Expect: 'DispatchToInnerBuilds', Actual: 'ResolveProjectReferences'.
   at Microsoft.VisualStudio.Telemetry.WindowsErrorReporting.WatsonReport.GetClrWatsonExceptionInfo(Exception exceptionObject)
===================

Is this expected?

[cartermp]

Can confirm the lack of language service light-up here - nothing, not even parsing operations, is showing up.

[cartermp]

@matthid Actually I think this is just the lack of multitargeting support in #4084, which should be fixed by #4286. If I change Fake.Runtime project file to to be <targetframework> rather than <targetframeworks> I get IDE feature light-up:

Is that working for you on 15.6 Preview 3? If so, we can just close this and re-open if #4286 doesn't fix this. Note that you won't be able to test #4286 yet, as it requires a Project System change that we're trying to pipe through the 15.6 release.

[Pilchie]

@lifengl - do you know what's up with the error above?

[KevinRansom]

@cartermp was correct, this is due to multi-targeting support not working.

In the latest internal build with the fix this project does colouring and intellisense :

[matthid]

Yes, thanks a lot for the quick info. Sorry I wasn't up to date with all the remaining issues.

[cartermp]

No worries! I'll close this out for now. We can re-open if it persists after the multitargeting work ships.