Useless-Code Detection and Elimination for PCF with Algebraic Data Types

We present a non-standard type assignment system and simplifications mappings for detecting and removing useless-code in simply typed functional programs with algebraic datatypes and recursive functions. We characterize two classes of useless-code: the dead-code , that is code that is never executed under the lazy-call-by-name evaluation, and the minimum-information-code , that is code that contributes to the computation only with a minimum amount of constant information.