type-design-performance

Design high-performance .NET types by sealing non-inheritance points to enable JIT devirtualization, preferring readonly structs for immutable values, and favoring static pure functions to reduce state and improve testability.

Seal .NET types at non-inheritance points to enable JIT devirtualization, which maximizes runtime efficiency. This is particularly important when designing new libraries and APIs or reviewing existing code for performance improvements.

Choose between class, struct, and record by preferring readonly structs for immutable value types and sealing classes where inheritance is unnecessary. This ensures efficient API boundaries and maximizes runtime performance.

Defer enumeration and return immutable collections at API boundaries to balance performance and semantics. This approach maintains immutable API boundaries while ensuring efficient data processing across libraries.

Static pure functions improve .NET performance by reducing state and improving testability. Converting instance methods to static pure functions where feasible eliminates hidden dependencies and enables better runtime optimization.

Yes, you can refactor an existing domain by sealing relevant types, converting small value types to readonly structs, and replacing instance methods with static pure functions where feasible to improve performance.