  Algebraic effect handlers are becoming increasingly popular way of
structuring and reasoning about effectful computations, and their performance
is often a concern. One of the proposed approaches towards efficient
compilation is tracking effect information through explicit subtyping
coercions. However, in the presence of polymorphism, these coercions are
compiled to additional arguments of compiled functions, incurring significant
overhead.
  In this paper, we present a polymorphic effectful calculus, identify
simplification phases needed to reduce the number of unnecessary constraints,
and prove they preserve the semantics. In addition, we implement the
simplification algorithm in the Eff language, and evaluate its performance on a
number of benchmarks. Though we do not prove optimality of presented
simplifications, the results show that the algorithm eliminates all the
coercions, resulting in a code as efficient as manually monomorphised one.
