dotnet/roslyn

Explicit method group conversion suppresses unnecessary qualification warning

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#1,208 opened on Mar 12, 2015

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Area-AnalyzersBughelp wanted

Description

using System;

class X {
    void M() { R((Action)this.M); }
    void R(Action a) { }
}

(Action) is highlighted as unnecessary, but this. isn't. Removing (Action) correctly highlights it in gray.

Typename qualifiers for static methods are similarly missed, but namespace qualifiers are not.

Contributor guide

Tech stack
csharp
Domain
tooling
Issue type
bug
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.
over 1 week
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#Roslyn compiler architecturecode analysisIDE features
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
20
Research direction
Investigate the Roslyn analyzer responsible for unnecessary qualification warnings. Look at the code for detecting qualifier redundancy, particularly the interaction with explicit method group conversions. The issue indicates that the warning is not triggered for 'this.' qualifier when an explicit cast is present, unlike namespace qualifiers. Start by examining the relevant diagnostic analyzer files in the Roslyn source, and check if there are any linked PRs or comments that might provide context.