@CyrusNajmabadi This is still in progress, primarily in tests, but can you take a look based on our design discussion the other day? This should mostly reflect what we discussed (IsSyntacticTriggerCharacterAsync) but I also ended up needing a ShouldProvidePreselectedItemsAsync.

Overall this looks good. A few concerns:

1. why is this only touching symbol completion? Does this not impact other completion providers? i.e. in gneeral, when symbol completion is shown, i often expect other completion providers as well (like keywords).
2. if we add this option, i would like VB to respect it. VB can just have 'null' map to 'true' though. But it would be really nice in VB to be able to disable this behavior and to keep our impls in sync.

@CyrusNajmabadi

why is this only touching symbol completion? Does this not impact other completion providers? i.e. in gneeral, when symbol completion is shown, i often expect other completion providers as well (like keywords).

We just want to update the scenarios in which symbols are shown to include these new cases. Why would other providers need to be updated? They'll come along as triggered or augmenting providers as always.

if we add this option, i would like VB to respect it. VB can just have 'null' map to 'true' though. But it would be really nice in VB to be able to disable this behavior and to keep our impls in sync.

I've filed this as #42369

Realizing I didn't tag @dotnet/roslyn-ide for additional review. So, tag.

The main contentious behavior change here is when SigHelp and Completion show up at the same time.

Previously, a user could type M( and immediately use the arrow keys to navigate through overloads. With this change, the arrow keys instead go to completion. If completion is dismissed (ESC), then the arrows work in SigHelp as desired.

Previously, a user could type M( and immediately use the arrow keys to navigate through overloads. With this change, the arrow keys instead go to completion. If completion is dismissed (ESC), then the arrows work in SigHelp as desired.

I'm not getting the value here. Why do these need to pop up on sig-help chars? Why not just have completion show up naturally (either direct invocation, or typing an id character)? Wouldn't that be enough to show the important items?

@CyrusNajmabadi Are there any remaining things we'd like to get done before an initial merge here? Can Explicit-SigHelp-Cancels-Completion come in a follow-up? /cc: @jinujoseph

@CyrusNajmabadi Are there any remaining things we'd like to get done before an initial merge here?

Nope. No more work here :)

Great work here btw! Impl is clean and fits nicely into an area that is extremely subtle. I'm def a little worried here, but that's mostly in IntelliCode's court now.

Can Explicit-SigHelp-Cancels-Completion come in a follow-up? /cc: @jinujoseph

Yes. That can come in a followup. Let's def concentrate on high value stuff right now. Just track the above in an issue. Thanks!

Follow-up issue tracked by #42484

Design meeting notes:

• Explicitly triggering signature help should dismiss completion.
• This is going to be a change for customer, we will leverage dogfooding to get customer feedback.