C# 7

[jnm2]

While working on #296, I'm running into cases where I want to use default literals or ?? throw or is var and out var. For example:

while (fullName.TryGetNextNamespaceSegment() is var segment && segment != null)
{
    // ...
}

Instead of:

for (;;)
{
    var segment = fullName.TryGetNextNamespaceSegment();
    if (segment == null) break;
    // ...
}

Since none of the projects have an explicit version set, and the solution already requires VS2017, and @oznetmaster doesn't transpile this codebase to C# 3, it seems like C# 7 is guaranteed to be available to anyone in the code. Does this mean we accept C# 7.0 code?

What about using <LangVersion>latest</LangVersion> or 7.1 or 7.2 so that I can use default literals or readonly structs? C# 7.1 requires VS 15.3 (or a package reference) and C# 7.2 requires VS 15.5 (or a package reference).

[OsirisTerje]

C# 7, yes. Latest, fine by me.

[jnm2]

You know what, I did mean this just as a question but I'm happy to help if there's something you had in mind.

[OsirisTerje]

1. Adding latest to all projects. As discussed earlier, there is no reason not to stay on the latest stable. If a problem arise from that, we just drop down to nearest downwards stable at that time.

But we should convert all to packagereference format first.

[jnm2]

@OsirisTerje Every csproj except the VSIX csproj is already using the new csproj SDK and PackageReference.
Last time I tried to convert a VSIX project to the new csproj SDK it didn't work. Is that something we should look into again?

Oh hey, look! I forgot I already added <LangVersion> latest to all the projects with C# source code, except empty-assembly and mock-assembly. Think that's good enough?

[jnm2]

💭 We could use PackageReference for the VSIX development-time dependency instead of https://github.com/nunit/nunit3-vs-adapter/blob/master/src/NUnit3TestAdapterInstall/packages.config. Should we?

[OsirisTerje]

@jnm2 Yes, we should.