Worked on the dotnet/fsharp repository to deliver a targeted performance optimization in the F# type subsystem, focusing on compiler design and functional programming. Addressed a performance regression in IDE mode with generative type providers by caching the result of TypeStructure.GetHashCode at creation time, storing it within the discriminated union case. This approach eliminated repeated O(n) hashing during type-subsumption cache lookups, reducing CPU usage and improving IDE responsiveness. Leveraged F# attributes such as [<CustomEquality; NoComparison>] to implement a fast-path Equals method, ensuring stable API behavior while enhancing maintainability and performance for projects relying on advanced type system features.