Exception for math.cube on real

Math

\[\left(x \cdot x\right) \cdot x\]

FPCore

(FPCore (x) :precision binary64 (* (* x x) x))

C

double code(double x) {
	return ((double) (((double) (x * x)) * x));
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2020203 
(FPCore (x)
  :name "math.cube on real"
  :precision binary64

  :herbie-target
  (pow x 3.0)

  (* (* x x) x))

Backtrace

first: contract violation expected: (and/c list? (not/c empty?)) given: '()		L	C
batch-eval-progs	/data/pavpan/nightlies/herbie/cleanup/src/programs.rkt	107	0
batch-errors	/data/pavpan/nightlies/herbie/cleanup/src/points.rkt	169	0
atab-add-altns	/data/pavpan/nightlies/herbie/cleanup/src/core/alt-table.rkt	194	0
(unnamed)	/opt/racket-7.5/collects/racket/contract/private/arrow-val-first.rkt	486	18
finalize-iter!	/data/pavpan/nightlies/herbie/cleanup/src/mainloop.rkt	273	0
run-iter!	/data/pavpan/nightlies/herbie/cleanup/src/mainloop.rkt	341	0
for-loop	/data/pavpan/nightlies/herbie/cleanup/src/mainloop.rkt	379	4
run-improve41	/data/pavpan/nightlies/herbie/cleanup/src/mainloop.rkt	360	0
.../more-scheme.rkt:261:28	unknown
run	/opt/racket-7.5/share/pkgs/profile-lib/main.rkt	39	2
profile-thunk16	/opt/racket-7.5/share/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/opt/racket-7.5/collects/racket/private/more-scheme.rkt	261	28

Reproduce

herbie shell --seed 2020203 
(FPCore (x)
  :name "math.cube on real"
  :precision binary64

  :herbie-target
  (pow x 3.0)

  (* (* x x) x))