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    SpecConstr: accommodate casts in value arguments · 5ab8094e
    Simon Peyton Jones authored
    This commit:
    
      commit fb050a33
      Author: Simon Peyton Jones <simonpj@microsoft.com>
      Date:   Thu Oct 12 11:00:19 2017 +0100
    
      Do not bind coercion variables in SpecConstr rules
    
    arranged to reject any SpecConstr call pattern that mentioned
    a coercion in the pattern.
    
    There was a good reason for that
    -- see Note [SpecConstr and casts] --
    but I didn't realise how important it was to accept patterns
    that mention casts in /terms/.  Trac #14936 showed this up.
    
    This patch just narrows the restriction to discard only
    the cases where the coercion is mentioned only in types.
    Fortunately that was pretty easy to do.
    5ab8094e
all.T 20.7 KB