CODEWITHSUNDEEP
c#roslynroslyn-code-analysis
meng
meng

Reputation: 461

Roslyn: Retrieving Symbol in parent or ancestor SyntaxNode

I'm writing a Roslyn analyzer to raise a diagnostic when a certain library method is used within a certain method in a certain kind of class, but I cannot retrieve the symbol in the parent or ancestor syntax nodes.

For example,

class C
{
    void M()
    {
        MyLibrary.SomeMethod();
    }
}

And this is the code for analyzing the SyntaxNode of SyntaxKind.InvocationExpression

private void AnalyzeNode(SyntaxNodeAnalysisContext context)
{
    var invocationExpression = context.Node as InvocationExpressionSyntax;
    var methodSymbol = context.SemanticModel.GetSymbolInfo(invocationExpression).Symbol as IMethodSymbol;
    if (methodSymbol == null) { return; }
    // check if it is the library method I am interested in. No problems here
    if (!methodSymbol.Name.Equals("SomeMethod") || 
        !methodSymbol.ContainingSymbol.ToString().Equals("MyNamespace.MyLibrary"))
    { return; }


    // this retrieves outer method "M".
    var outerMethodSyntax = invocationExpression.FirstAncestorOrSelf<MethodDeclarationSyntax>();
    if (outerMethodSyntax == null) { return; }

    // symbol.Symbol is always null here
    var symbol = context.SemanticModel.GetSymbolInfo(outerMethodSyntax);
    ...

So my question is, is it possible to retrieve SymbolInfo from an ancestor SyntaxNode.

Is my approach correct or should I try another approach?

Upvotes: 8

Views: 2244

Answers (1)

meng
meng

Reputation: 461

Thanks Jeroen Vannevel! I needed to use semanticModel.GetDeclaredSymbol()

Upvotes: 5

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