Error in 0.0ms

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019067 +o rules:numerics
(FPCore (x.re x.im)
  :name "math.cube on complex, imaginary part"

  :herbie-target
  (+ (* (* x.re x.im) (* 2 x.re)) (* (* x.im (- x.re x.im)) (+ x.re x.im)))

  (+ (* (- (* x.re x.re) (* x.im x.im)) x.im) (* (+ (* x.re x.im) (* x.im x.re)) x.re)))

Backtrace

build-list: contract violation expected: exact-nonnegative-integer? given: '(0)		L	C
build-list	/opt/racket-7.0/collects/racket/private/list.rkt	296	2
debug-print	/data/pavpan/nightlies/herbie/develop/src/debug.rkt	107	0
run-improve43	/data/pavpan/nightlies/herbie/develop/src/mainloop.rkt	346	0
(unnamed)	/opt/racket-7.0/collects/racket/private/more-scheme.rkt	261	28
run	/opt/racket-7.0/share/pkgs/profile-lib/main.rkt	39	2
profile-thunk16	/opt/racket-7.0/share/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/opt/racket-7.0/collects/racket/private/more-scheme.rkt	261	28