I'm on the fence about this, standardization let's people pool resources to provide common functionality, but it also ossifies the interface so that doing anything not supported by the interface becomes harder than before. The first thing that pops into my head is that for languages with interprocedural type inference, I really want my IDE to show me what types it has inferred, but this is outside the spec and not ev…
wouldn't inferred types fit into the "Diagnostic" interface? There are both "info" and "hint" levels which seem appropriate. (I don't disagree with your general point, just curious about this specific example)
Sort of; the hover interface helps, but I would prefer it if the IDE showed it as if it was written there explicitly, not just when you hover over it.
Which requires explicit UI work, which this protocol won't support.