Changes between Version 3 and Version 4 of TypeFunctionsSolving


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Timestamp:
Jul 22, 2008 7:16:52 AM (6 years ago)
Author:
chak
Comment:

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  • TypeFunctionsSolving

    v3 v4  
    1414The types `t`, `t1`, ..., `tn` may not contain any occurrences of synonym families.  Moreover, in Forms (2) & (3), the left- and right-hand side need to be different, and the left-hand side may not occur in the right-hand side. 
    1515 
    16 Coercions `co` are either wanteds (represented by a flexible type variable) or givens ''aka'' locals (represented by a type term of kind CO). 
    17  
    1816NB: We explicitly permit equalities of the form `x ~ y` and `a ~ b`, where both sides are either flexible or rigid type variables. 
    1917 
    20 In GHC, `TcTyFuns.RewriteInst` represents normal equalities, emphasising their role as rewrite rules. 
     18Coercions `co` are either wanteds (represented by a flexible type variable) or givens ''aka'' locals (represented by a type term of kind CO).  In GHC, they are represented by `TcRnTypes.EqInstCo`.   Moreover, `TcTyFuns.RewriteInst` represents normal equalities, emphasising their role as rewrite rules. 
    2119 
    2220