Changes between Version 23 and Version 24 of Status/Oct10


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Timestamp:
Nov 1, 2010 12:36:02 PM (3 years ago)
Author:
simonpj
Comment:

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  • Status/Oct10

    v23 v24  
    33GHC is humming along.  We are currently deep into the release cycle for GHC 7.0.  We have finally bumped the major version number, because GHC 7.0 has quite a bit of new stuff 
    44 
    5  * As long promised, Simon PJ and Dimitrios have spent a good chunk of the summer doing a complete rewrite of the constraint solver in the type inference engine.  Because of GHC's myriad type-system extensions, especially GADTs and type families, the old engine had begun to resemble the final stages of a game of Jenga.  It was a delicately-balanced pile of blocks that lived in constant danger of complete collapse, and had become extremely different to modify (or even to understand).  The new inference engine is much more modular and robust; it is described in detail in our paper [[http://haskell.org/haskellwiki/Simonpj/Talk:OutsideIn OutsideIn]].  A blog post describes some consequential changes to let generalisation [!LetGen]. 
     5 * As long promised, Simon PJ and Dimitrios have spent a good chunk of the summer doing a complete rewrite of the constraint solver in the type inference engine.  Because of GHC's myriad type-system extensions, especially GADTs and type families, the old engine had begun to resemble the final stages of a game of Jenga.  It was a delicately-balanced pile of blocks that lived in constant danger of complete collapse, and had become extremely different to modify (or even to understand).  The new inference engine is much more modular and robust; it is described in detail in our paper [[http://haskell.org/haskellwiki/Simonpj/Talk:OutsideIn OutsideIn]].  A blog post describes some consequential changes to let generalisation [[http://hackage.haskell.org/trac/ghc/blog/LetGeneralisationInGhc7 LetGen]]. 
    66 
    77 As a result we have closed dozens of open type inference bugs, especially related to GADTs and type families. 
     
    9696 
    9797 * [!LetGen] "Let generalisation in GHC 7.0", Peyton Jones, blog post Sept 2010, http://hackage.haskell.org/trac/ghc/blog/LetGeneralisationInGhc7 
     98 
    9899 * [Newtype] "Generative Type Abstraction and Type-level Computation", Weirich, Zdancewic, Vytiniotis, and Peyton Jones, POPL 2010, http://www.cis.upenn.edu/~sweirich/newtypes.pdf 
    99100