NamedExtraConstraintsWildcard.hs:5:1: error: [GHC-05617]
    • Could not deduce ‘w0’
      from the context: (Eq a, w)
        bound by the inferred type for ‘foo’:
                   forall a {w :: Constraint}. (Eq a, w) => a -> a
        at NamedExtraConstraintsWildcard.hs:5:1-15
    • In the ambiguity check for the inferred type for ‘foo’
      To defer the ambiguity check to use sites, enable AllowAmbiguousTypes
      When checking the inferred type
        foo :: forall a {w :: Constraint}. (Eq a, w) => a -> a