Changes between Version 408 and Version 409 of TypeFunctionsStatus


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Timestamp:
Oct 21, 2008 12:16:16 PM (5 years ago)
Author:
chak
Comment:

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  • TypeFunctionsStatus

    v408 v409  
    2121 * Constraint simplification: 
    2222  * #2664 (typechecker diverges; actually, it's after Tc9, probably during zonking) 
    23   * #2102 & 2715 (superclass equalities) 
     23  * #2102 & #2715 (superclass equalities) 
    2424    * To fix superclass equalities (specifically getting the coercion evidence), we could introduce a kind of typelet just for evidence.  In fact, re-use `HsBind.VarBind` and make its right-hand side a specially data structure describing evidence construction, instead of being a general `HsExpr`.  That evidence construction generation can have a case for extracting superclass constraints.  The desugarer than has to generate the case expression bringing the equality in scope from that. 
    2525    * What about filtering the `EqInst`s in `TcSimplify.addSCs`.  We need them, don't we?  But they give rise to `Var`s, not `Id`s, and we haven't got selectors.