Modular type checking of anchored exception declarations

• We present modular algorithms for type checking anchored exception declarations.
• The modular algorithms provide additional opportunities for using anchored exception declarations.
• We prove that the modular algorithms preserve exception safety.

Checked exceptions improve the robustness of software, but they also decrease its adaptability because they must be propagated explicitly, and because they must often be handled even if they cannot be thrown. Anchored exception declarations solve both problems by allowing a method to declare its exceptional behavior in terms of other methods.The original type checking analyses for anchored exception declarations, however, are not modular. In this paper, we present algorithms for modular verification of soundness in an object-oriented language without parametric polymorphism.