VB: language version flag 15.3 not properly passed to project system

[jcouv]

Repro:

• Create a VB proj and set language version to 15.3 (in the proj file)
• Type a tuple with inferred names and use the inferred names
• If you build the project, it will build properly
• But the IDE will show red squiggles (it is using language version Default)

[AdamSpeight2008]

Default is tied to latest major release, 15.0.
How are you changing the language? Manually editing the actual .vbproj file?

[jcouv]

From discussion with @srivatsn, only the new project system has a generic way of passing the whole command-line through.
The old project system has to go through the un-managed API (CVbcMSBuildHostObject::SetLanguageVersion). That method needs to convert from language version as a string ("15.3") to an enum value (VisualBasic15_3 = 1503 in this case).
Note: the corresponding method for Csc (CCscMSBuildHostObject::SetLangVersion) doesn't have that problem (it is just a pass-through).

@srivatsn It would be great if someone from your team could help with that. Thanks

FYI @jasonmalinowski

[jcouv]

One more thing: while making this change, let's also make sure that language version "Latest" is passed properly (Latest = Integer.MaxValue, but it's probably better to pass the specific version, 1503).

[srivatsn]

Can you file a bug in the project-system repo for this?

[jcouv]

Issue moved to dotnet/project-system #2088 via ZenHub

[jcouv]

Looks like we can fix this without project system change. Re-opening compiler issue.

[jcouv]

Fixed by #19112

[AdamSpeight2008]

@jcouv Are you sure this is fixed as i am using 15.8.0 Preview 1.1 and it doesn't seem to be passing the language version.

[jcouv]

@AdamSpeight2008 I tried it just now (Version 15.8.0 Preview 2.0 [27715.0.d15.8]) by creating a VB class library with .NET Framework, then using a VB 15.5 feature (non-trailing named arguments), manually setting the <LangVersion>15.5</LangVersion> in the project file, and it worked as expected.

If there is an issue that you can repro, please file it with details in the project-systems repo (consider linking to dotnet/project-system#3411 which was the most recently fixed issue regarding VB and LangVersion).
Thanks