Error in 0.0ms

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019067 +o rules:numerics
(FPCore (a b c)
  :name "Area of a triangle"
  :pre (and (< 0 a) (< 0 b) (< 0 c))
  (sqrt (* (* (* (/ (+ (+ a b) c) 2) (- (/ (+ (+ a b) c) 2) a)) (- (/ (+ (+ a b) c) 2) b)) (- (/ (+ (+ a b) c) 2) c))))

Backtrace

build-list: contract violation expected: exact-nonnegative-integer? given: '(0)LC
build-list/opt/racket-7.0/collects/racket/private/list.rkt2962
debug-print/data/pavpan/nightlies/herbie/develop/src/debug.rkt1070
run-improve43/data/pavpan/nightlies/herbie/develop/src/mainloop.rkt3460
(unnamed)/opt/racket-7.0/collects/racket/private/more-scheme.rkt26128
run/opt/racket-7.0/share/pkgs/profile-lib/main.rkt392
profile-thunk16/opt/racket-7.0/share/pkgs/profile-lib/main.rkt90
(unnamed)/opt/racket-7.0/collects/racket/private/more-scheme.rkt26128