Diagnostic that spans across projects

[sharwell]

I'd like to implement a diagnostic analyzer that spans across Projects in a Solution. Is it possible to get this information within a diagnostic analyzer?

For reference, this is part of implementing the following:
openstacknetsdk/OpenStackNetAnalyzers#16

[tmeschter]

Analyzers are currently project-centric; they can't "see" anything outside of the project currently being built, including other projects.

That being said, there may be another approach that can achieve what you want right now. Projects now support additional files--text files that aren't source code but are passed to the compilers and available to analyzers. You could have the .NET SDK projects share an additional file documenting the set of expected classes and members, and an analyzer that complains if they don't.

The Roslyn projects currently use this approach to enforce that the public API surface is documented in an additional file; this makes changes to the public API very obvious in code reviews and such. See https://github.com/dotnet/roslyn/blob/master/src/Diagnostics/Roslyn/Core/ApiDesign/DeclarePublicAPIAnalyzer.cs.

[srivatsn]

Solution wide analyzers are not currently supported. We'll use this issue to track the feature request.