Changes between Version 29 and Version 30 of TypeFunctionsSolving


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Timestamp:
Aug 3, 2008 10:07:43 AM (6 years ago)
Author:
chak
Comment:

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  • TypeFunctionsSolving

    v29 v30  
    177177..we stop here if (Local) doesn't apply to flexible tyvars 
    178178}}} 
    179 A serious disadvantage of this approach is that we '''do''' want to use Rule (Local) with flexible type variables as soon as we have rank-n signatures.  In fact, the lack of doing so is responsible for a few Trac bugs in the GHC implementation of (!SkolemOccurs). 
     179A serious disadvantage of this approach is that we '''do''' want to use Rule (Local) with flexible type variables as soon as we have rank-n signatures.  In fact, the lack of doing so is responsible for a few failing tests in the testsuite in the GHC implementation of (!SkolemOccurs). 
    180180 
    181181'''De-prioritise Rule (Local)''': Instead of outright forbidding the use of Rule (Local) with flexible type variables, we can simply require that Local is only used if no other rule is applicable.  (That has the same effect on satisfiable queries, and in particular, the present example.)