DefaultSink returns a default sink that simply logs output to stderr/stdout.

Message returns an anonymous diagnostic message without any source or ID information.

RawMessage returns an anonymous diagnostic message without any source or ID information that will not be rendered with Sprintf.

StreamMessage returns an anonymous diagnostic message without any source or ID information that is associated with the given stream ID.

Diag is an instance of an error or warning generated by the compiler.

FormatOptions controls the output style and content.

Sink facilitates pluggable diagnostics messages.

ID is a unique diagnostics identifier.

Severity dictates the kind of diagnostic.