dotnet/roslyn

GetSymbolInfo for a get property returns an overriden property without a get

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#5,659 opened on Oct 2, 2015

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Area-CompilersBugConcept-APIhelp wanted

Description

public class A: B{
    public override int Q{ set{ base.Q = value; } }

    public void foo(int x){
    }

    public void test(){
        foo(Q);
    }

    public static void Main(string[] args){
    }
}

public class B{
    public virtual int Q{ get; set; }
}

Calling model.GetSymbolInfo on the argument 'Q' in the call to 'foo' returns an IPropertySymbol defined by class A, which does not have a GetMethod. To get the GetMethod used, I have to look at the OverridenProperty attribute of the returned symbol to find B.get_Q.

It seems like Roslyn should bind the 'Q' expression directly to the B.Q property. Presumably this does not occur because Roslyn does not take the context of the property into account, meaning that it doesn't look at if the property is used in a get/set context, and rather that simply the name is resolved to the 'closest' definition of the property.

Roslyn 1.0.0

Contributor guide

Tech stack
csharp
Domain
toolingdeveloper experience
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
5
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.
mostly clear
Prerequisites
Understanding of C# property overridingFamiliarity with Roslyn API
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
10
Research direction
The issue is about Roslyn's binding logic for property access in get/set contexts. Investigate how the compiler resolves the symbol for 'Q' in a method call argument. Look at the SemanticModel.GetSymbolInfo method and the related binding code. The fix likely involves checking the context (get vs set) before resolving the property symbol. Examine existing tests for similar binding scenarios.