[WIP, RFC FS-1063] Add let! ... and! ... syntax

[TD5]

Implementation of F# RFC FS-1063 Applicatives syntax

Not ready for prime time, just a proof-of-concept right now.

[TD5]

@thinkbeforecoding That is out of scope for the current change, as far as I am concerned. However, I see no reason why this could not be done, especially in light of the prior art. Have you considered creating an fslang suggestion for this if there isn't one already?

[cartermp]

@thinkbeforecoding I agree that this is out of scope for this PR (and corresponding RFC), but a further issue in fslang would be welcome. We can see if it makes sense to turn into an RFC and fold into the language separately from this PR.

[cartermp]

@TD5 Looks like some of the IDE completion tests are failing now. Can you take a look?

[TD5]

Yep 👍 I’ve had my eye on it for a while and some theories as to what is going on but I’ve not been able to build the vs bits on my machine so it has been tricky.

…

On 16 Oct 2018, at 18:25, Phillip Carter ***@***.***> wrote: @TD5 Looks like some of the IDE completion tests are failing now. Can you take a look? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub, or mute the thread.

[cartermp]

@TD5 If you install:

• .NET Desktop workload + F# desktop templates component
• Visual Studio Extensibility workload

And if you use the VS command line in admin mode with build vs does it succeed?

[TD5]

@cartermp, in the end I just installed everything under the sun and the tests are now running via build.cmd, so that's a big step forward.

[TD5]

Pull request tests don't seem to have kicked off - don't trust the supposed greenness of the build!

[TD5]

The tests run and fail locally as on CI when I run build.cmd release ci_part1, so that's working.

When I run in what I think is the !FSCBINPATH! directory (visualfsharp\release\net40\bin) and tack on --test=Tests.LanguageService.AutoCompletion.UsingProjectSystem.CompletionInDifferentEnvs5 to the command that I think build.cmd release ci_part1 kicks off:

"C:\Users\Tom\Documents\FSharpContribs\visualfsharp\packages\NUnit.Console.3.0.0\tools\nunit3-console.exe" --verbose --x86 --framework:V4.0 --result:"C:\Users\Tom\Documents\FSharpContribs\visualfsharp\tests\TestResults\test-vs-ideunit-results.xml;format=nunit3" --output:"C:\Users\Tom\Documents\FSharpContribs\visualfsharp\tests\TestResults\test-vs-ideunit-output.log"  --err:"C:\Users\Tom\Documents\FSharpContribs\visualfsharp\tests\TestResults\test-vs-ideunit-errors.log"  --work:"C:\Users\Tom\Documents\FSharpContribs\visualfsharp\release\net40\bin"  --workers=1 --agents=1 --full "C:\Users\Tom\Documents\FSharpContribs\visualfsharp\release\net40\bin\VisualFSharp.UnitTests.dll" --test=Tests.LanguageService.AutoCompletion.UsingProjectSystem.CompletionInDifferentEnvs5

I still see the same error as the one VS gives me:

NUnit Console Runner 3.0.5797
Copyright (C) 2015 Charlie Poole

Runtime Environment
   OS Version: Microsoft Windows NT 10.0.17134.0
  CLR Version: 4.0.30319.42000

Test Files
    C:\Users\Tom\Documents\FSharpContribs\visualfsharp\release\net40\bin\VisualFSharp.UnitTests.dll

Test Filters
    Test: Tests.LanguageService.AutoCompletion.UsingProjectSystem.CompletionInDifferentEnvs5

Agent process 4316 starting
Running under version 4.0.30319.42000, Net 4.5
Agent process 4316 exiting

Errors and Failures

1) TearDown Error : Tests.LanguageService.AutoCompletion.UsingProjectSystem
System.IO.FileNotFoundException : Could not load file or assembly 'Microsoft.VisualStudio.LanguageServices, Version=2.9.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.
TearDown : System.NullReferenceException : Object reference not set to an instance of an object.
   at UnitTests.TestLib.LanguageService.LanguageServiceBaseTests.Init()
--TearDown
   at UnitTests.TestLib.LanguageService.LanguageServiceBaseTests.Cleanup()

2) Error : Tests.LanguageService.AutoCompletion.UsingProjectSystem.CompletionInDifferentEnvs5
OneTimeSetUp: System.IO.FileNotFoundException : Could not load file or assembly 'Microsoft.VisualStudio.LanguageServices, Version=2.9.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.

Run Settings
    RuntimeFramework: V4.0
    RunAsX86: True
    WorkDirectory: C:\Users\Tom\Documents\FSharpContribs\visualfsharp\release\net40\bin
    MaxAgents: 1
    NumberOfTestWorkers: 1
    Verbose: True

Test Run Summary
    Overall result: Failed
   Tests run: 1, Passed: 0, Errors: 1, Failures: 0, Inconclusive: 0
     Not run: 0, Invalid: 0, Ignored: 0, Explicit: 0, Skipped: 0
  Start time: 2018-10-23 10:49:14Z
    End time: 2018-10-23 10:49:14Z
    Duration: 0.215 seconds

Results (nunit3) saved as C:\Users\Tom\Documents\FSharpContribs\visualfsharp\tests\TestResults\test-vs-ideunit-results.xml

I'm sure I am just missing something basic like an environment variable since build.cmd release ci_part1 works and it doesn't seem to clean up any build artefacts. Does anyone have any ideas?#

Perhaps @cartermp? From what I can tell, everything relevant in the VS installer is now installed, although I'm not sure which thing corresponds to "F# desktop templates component", but I have "F# desktop language support", "F# language support" and "F# language support for web projects". build.cmd vs succeeds.

[dsyme]

@TD5 - I updated this to master by push to your branch. I'll aim to review it and use it next, and look at unresolved issues.

[TD5]

That’s excellent news! Thanks for taking an interest!

Let me know if you have any questions. From what I recall, the outstanding issue from my perspective was the effect on auto completion in VS (there are some tests labelled as something akin to “legacy Visual Studio” that are affected).

[dsyme]

I would like to revive this work and get it into F# 5.x

That's quite a lot of conflicts now, I'll see if I can resolve

[dsyme]

OK, merged with master

[dsyme]

I will resubmit this in a new PR

[dsyme]

Replaced by #7756 to make sure the feature comes from a feature branch