dotnet/roslyn

Signature help for delegate types

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#46,190 opened on Jul 21, 2020

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Area-IDEIDE-IntelliSensehelp wanted

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Description

If you're looking at this, ready to type a lambda, how do you know what to type next?

image

If it's Func<...> or Action<...> it's easy. For two or three others, I have the signature memorized and can translate the generic types in my head to the appropriate locations (e.g. Predicate<X>). For 99% of delegate types, it's a bunch of F12ing or F1ing every time.

Could signature help show something like this?

ParseArgument<SemanticVersion> is (ArgumentResult result) => SemanticVersion

@CyrusNajmabadi mentioned that something similar is already shown for anonymous types: image

🔗 Also reported at AB#1244148

Contributor guide

Research direction
Investigate how Roslyn provides signature help for named delegates by examining the existing implementation for anonymous types and extending it to cover all delegate types.
Tech stack
csharp
Domain
developer experience
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
C#Roslyn
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50