Hello!
Type checker returns an error while translating this piece of code:
(: permutations ((Listof Index) -> (Listof (Listof Index))))
(define (permutations lst)
(cond
[(empty? lst) '(())]
[else (for*/list: : (Listof (Listof Index))
([x : Index (in-list lst)]
[y : (Listof Index) (in-list (permutations (remq x lst)))])
(cons x y))]))
'Type Checker: Error in macro expansion -- insufficient type information to
typecheck. please add more type annotations in: (for*/list: : (Listof (Listof
Index)) ((x : Index (in-list lst)) (y : (Listof Index) (in-list (remq x lst))))
(cast (cons x y) (Listof Index)))'
Is it possible to give more type annotations in this case?
Sergey Samoylenko.
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