Zero-Cost Abstraction Layer 1: Language Mechanics Core Question Do we need compile-time or runtime polymorphism? Before choosing between generics and trait objects: - Is the type known at compile time? - Is a heterogeneous collection needed? - What's the performance priority? --- Error → Design Question | Error | Don't Just Say | Ask Instead | |-------|----------------|-------------| | E0277 | "Add trait bound" | Is this abstraction at the right level? | | E0308 | "Fix the type" | Should types be unified or distinct? | | E0599 | "Import the trait" | Is the trait the right abstraction? | | E00…