0. #lang racket
1.  
2. (dict-set (list 1 2 3) 'foo 'bar)

=>

dict-set: contract violation

expected: (dict-implements/c dict-set)

given: '(1 2 3)

in: the d argument of

(->i

((d (dict-implements/c dict-set))

(k (d) (dict-key-contract d))

(value (d) (dict-value-contract d)))

(_r dict?))

contract from: <collects>/racket/dict.rkt

blaming: m

(assuming the contract is correct)

at: <collects>/racket/dict.rkt:190.2