C# Interactive doesn't work with tuple syntax when desktop framework 4.7 is installed

[paulomorgado]

Version Used:
Microsoft Visual Studio Enterprise 2017 RC 15.9.9-RC4+26206.0
Microsoft (R) Visual C# Interactive Compiler version 2.0.0.61404

Steps to Reproduce:

• Microsoft Visual Studio Enterprise 2017 RC 15.9.9-RC4+26206.0

1. Open the C# Interactive window.
2. Enter (1,2)

• Microsoft (R) Visual C# Interactive Compiler version 2.0.0.61404

1. Run csi.exe
2. Enter (1,2)

Expected Behavior:
Outputs [(1, 2)]

Actual Behavior:

• Microsoft Visual Studio Enterprise 2017 RC 15.9.9-RC4+26206.0
  (1,13): error CS8179: Predefined type 'System.ValueTuple`2' is not defined or imported

• Microsoft (R) Visual C# Interactive Compiler version 2.0.0.61404
  (1,1): error CS8179: Predefined type 'System.ValueTuple`2' is not defined or imported
  (1,1): error CS0029: Cannot implicitly convert type '(string, int)' to 'object'

Workaround

• Microsoft Visual Studio Enterprise 2017 RC 15.9.9-RC4+26206.0

Remove

/r:System.ValueTuple.dll

From

C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\Common7\IDE\CommonExtensions\Microsoft\ManagedLanguages\VBCSharp\InteractiveComponents\CSharpInteractive.rsp

• Microsoft (R) Visual C# Interactive Compiler version 2.0.0.61404

Remove

/r:System.ValueTuple.dll

From

C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin\Roslyn\csi.rsp

[tmat]

The important piece of information here is that the machine has a pre-release version of .NET Framework 4.7

[paulomorgado]

Or, if you think as a customer, the customer installed VS2017 and tuples don't work on interactive environments.

Isn't .NET Framework 4.7 a requirement of VS2017? I sure didn't explicitly install it.

[tmat]

It is not. Windows Insider update would install it.

[paulomorgado]

OK!

I've noticed that, although the interactive uses the mscorlib ValueTuple, in projects (.NET Framework or .NET Core), the System.ValueTuple package is required.

[jcouv]

Fixed by #17192 (this let the EE and Interactive handle the duplicate ValueTuple type and pick the one from the app instead of the one from mscorlib).
I expect the fix to make it into 15.3 (summer timeframe, based on my understanding).

There will also be a follow-up to have GAC type unification, so the compiler workaround isn't needed (targeting desktop 4.7.1 framework).

[paulomorgado]

@jcouv, does "summer timeframe" mean that the problem will be in VS2017RTM?

[jcouv]

Yes. At this point RTM has a very high bar for accepting fixes (crashes and such). So this fix didn't make it into RTM. Sorry about that.

[paulomorgado]

At least, make that noticeable in the release notes and release a script to fix .rsp files.

[thomaslevesque]

I just hit the same issue. @paulomorgado's fix doesn't seem to work for me, I still get the same error.

[paulomorgado]

Run this:

Get-ChildItem -LiteralPath 'C:\Program Files (x86)\Microsoft Visual Studio\' -Filter '*.rsp' -Recurse | Select-String -SimpleMatch '/r:System.ValueTuple.dll'

You'll see which rsp files have the reference.

[thomaslevesque]

Thanks @paulomorgado, that was it. I had a csi.rsp in C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin\Roslyn\csi.rsp

[paulomorgado]

Beware of any VS updates. I think it will "repair" that.