Visual Basic language specification
The Visual Basic Language Specification is the authoritative source for answers to all questions about Visual Basic grammar and syntax. It contains detailed information about the language, including many points not covered in the Visual Basic reference documentation.
The specification is available on the Microsoft Download Center.
This site contains the Visual Basic 11 specification. It's built from the Markdown files contained in the dotnet/vblang GitHub repository.
Issues on the specification should be created in the dotnet/vblang repository. Or, if you're interested in fixing any errors you find, you can submit a Pull request to the same repository.