Worked on the dotnet/sdk repository to enhance the reliability of static code analysis by addressing a critical issue in the Roslyn analyzer’s CastWillAlwaysFail path. Focused on improving the DerivesFrom type symbol handling, the developer used unaliased TypeSymbols in C# to ensure accurate detection of InvalidCastException risks in generic-derived type hierarchies. This update reduced false positives and negatives, strengthening code health checks for downstream consumers. The work included adding a dedicated unit test to prevent regression and removing reliance on OriginalDefinition for class-type comparisons, demonstrating strong skills in code analysis, type systems, and software testing within the .NET ecosystem.