Abstract. The combination of parameter polymorphism, subtyping extended to qualified and polymorphic types, and polymorphic recursion is useful in standard type inference and gives expressive type-based program analyses, but raises difficult algorithmic problems. In a program analysis context we show how Mycroft's iterative method of computing principal types for a type system with polymorphic recursion can be generalized and adapted to work in a setting with subtyping. This does not only yield a proof of existence of principal types (most general properties), but also an algorithm for computing them. The punch-line of the development is that a very simple modification of the basic algorithm reduces its computational complexity from exponential time to polynomial time relative to the size of the given, explicitly typed program.This solves the open problem of finding an inference algorithm for polymorphic binding-time analysis [7].

In his PEPM'93 paper Mogensen introduced a new off-line specialisation technique, constructor specialisation. What from specialised versions of the specialiser.

bstractWe extend type specialisation to a computational lambda calculus with first-class references. The resulting specialiser has been used to specialise a self-interpreter for this typed computational lambda calculus optimally.Furthermore, this spccialiser can perform operations on references at specialisation time, when possible.

We extend type specialisation to a computational lambda calculus with first-class references. The resulting specialiser has been used to specialise a self-interpreter for this typed computational lambda calculus optimally. Furthermore, this specialiser can perform operations on references at specialisation time, when possible.

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