Signature help not offered in positional pattern.

Description

public class Point
{
    public int X;
    public int Y;
    public void Deconstruct(out int XX, out int YY) => throw null;
    void M()
    {
        object o = null;
        if (o is Point($)) // <-- i should get sighelp here to make it clear what is being matched
        {

        }
    }
}

Contributor guide

Tech stack

csharp

Domain

developer experiencetooling

Issue type

feature

DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.

4

Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.

1-2 days

Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.

stale

ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.

clear

Prerequisites

C# knowledgefamiliarity with Roslyn syntax

Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.

20

Research direction

Examine the existing signature help providers in the Roslyn EditorFeatures layer, particularly for pattern matching constructs. The issue requests that when typing a positional pattern like `is Point($)`, signature help should show the parameters of `Deconstruct`. Look at how signature help is triggered for deconstruction in other contexts (e.g., variable declarations). Investigate the `ISignatureHelpProvider` implementations and the syntax handling for positional patterns. The maintainers may have provided guidance in the issue comments.