Diagnosing type errors with class

Danfeng Zhang, Andrew C. Myers, Dimitrios Vytiniotis, Simon Peyton-Jones

Research output: Chapter in Book/Report/Conference proceedingConference contribution

15 Scopus citations

Abstract

Type inference engines often give terrible error messages, and the more sophisticated the type system the worse the problem. We show that even with the highly expressive type system implemented by the Glasgow Haskell Compiler (GHC)-including type classes, GADTs, and type families-it is possible to identify the most likely source of the type error, rather than the first source that the inference engine trips over. To determine which are the likely error sources, we apply a simple Bayesian model to a graph representation of the typing constraints; the satisfiability or unsatisfiability of paths within the graph provides evidence for or against possible explanations. While we build on prior work on error diagnosis for simpler type systems, inference in the richer type system of Haskell requires extending the graph with new nodes. The augmentation of the graph creates challenges both for Bayesian reasoning and for ensuring termination. Using a large corpus of Haskell programs, we show that this error localization technique is practical and significantly improves accuracy over the state of the art.

Original languageEnglish (US)
Title of host publicationPLDI 2015 - Proceedings of the 36th ACM SIGPLAN Conference on Programming Language Design and Implementation
EditorsSteve Blackburn, David Grove
PublisherAssociation for Computing Machinery
Pages12-21
Number of pages10
ISBN (Electronic)9781450334686
DOIs
StatePublished - Jun 3 2015
Event36th ACM SIGPLAN Conference on Programming Language Design and Implementation, PLDI 2015 - Portland, United States
Duration: Jun 13 2015Jun 17 2015

Publication series

NameProceedings of the ACM SIGPLAN Conference on Programming Language Design and Implementation (PLDI)
Volume2015-June

Other

Other36th ACM SIGPLAN Conference on Programming Language Design and Implementation, PLDI 2015
CountryUnited States
CityPortland
Period6/13/156/17/15

All Science Journal Classification (ASJC) codes

  • Software

Fingerprint Dive into the research topics of 'Diagnosing type errors with class'. Together they form a unique fingerprint.

Cite this