Cozy: synthesizing collection data structures

Many applications require specialized data structures not found in standard libraries. Implementing new data structures by hand is tedious and error-prone. To alleviate this difficulty, we built a tool called Cozy that synthesizes data structures using counter-example guided inductive synthesis. We evaluate Cozy by showing how its synthesized implementations compare to handwritten implementations in terms of correctness and performance across four real-world programs. Cozy's data structures match the performance of the handwritten implementations while avoiding human error.