Principal type inference for GHCstyle multi-parameter type classes (2006)
| Venue: | In Proc. of APLAS’06 |
| Citations: | 4 - 4 self |
BibTeX
@TECHREPORT{Sulzmann06principaltype,
author = {Martin Sulzmann and Tom Schrijvers and Peter J. Stuckey},
title = {Principal type inference for GHCstyle multi-parameter type classes},
institution = {In Proc. of APLAS’06},
year = {2006}
}
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Abstract
Abstract. We observe that the combination of multi-parameter type classes with existential types and type annotations leads to a loss of principal types and undecidability of type inference. This may be a surprising fact for users of these popular features. We conduct a concise investigation of the problem and are able to give a type inference procedure which, if successful, computes principal types under the conditions imposed by the Glasgow Haskell Compiler (GHC). Our results provide new insights on how to perform type inference for advanced type extensions. 1 Introduction Type systems are important building tools in the design of programming lan-guages. They are typically specified in terms of a set of typing rules which are formulated in natural deduction style. The standard approach towards estab-lishing type soundness is to show that any well-typed program cannot go wrong at run-time. Hence, one of the first tasks of a compiler is to verify whether aprogram is well-typed or not.
