Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2020271 
(FPCore (a b c)
  :name "jeff quadratic root 1"
  :precision binary64
  (if (>= b 0.0) (/ (- (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))) (* 2.0 a)) (/ (* 2.0 c) (+ (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))))))

Backtrace

match: no matching clause for 'real		L	C
match:error	/opt/racket-7.8/collects/racket/match/runtime.rkt	24	0
f391	unknown
munge	/data/pavpan/nightlies/herbie/egg-taylor/src/programs.rkt	149	2
for-loop	/data/pavpan/nightlies/herbie/egg-taylor/src/programs.rkt	168	15
f391	unknown
munge	/data/pavpan/nightlies/herbie/egg-taylor/src/programs.rkt	149	2
for-loop	/data/pavpan/nightlies/herbie/egg-taylor/src/programs.rkt	168	15
f391	unknown
munge	/data/pavpan/nightlies/herbie/egg-taylor/src/programs.rkt	149	2
for-loop	/data/pavpan/nightlies/herbie/egg-taylor/src/programs.rkt	168	15
f391	unknown
munge	/data/pavpan/nightlies/herbie/egg-taylor/src/programs.rkt	149	2
munge	/data/pavpan/nightlies/herbie/egg-taylor/src/programs.rkt	149	2
for-loop	/data/pavpan/nightlies/herbie/egg-taylor/src/programs.rkt	179	4
batch-eval-progs	/data/pavpan/nightlies/herbie/egg-taylor/src/programs.rkt	125	0
batch-errors	/data/pavpan/nightlies/herbie/egg-taylor/src/points.rkt	169	0
atab-add-altns	/data/pavpan/nightlies/herbie/egg-taylor/src/core/alt-table.rkt	194	0
(unnamed)	/opt/racket-7.8/collects/racket/contract/private/arrow-val-first.rkt	486	18
finalize-iter!	/data/pavpan/nightlies/herbie/egg-taylor/src/mainloop.rkt	285	0
run-iter!	/data/pavpan/nightlies/herbie/egg-taylor/src/mainloop.rkt	353	0
run-improve	/data/pavpan/nightlies/herbie/egg-taylor/src/mainloop.rkt	372	0
(unnamed)	/data/pavpan/nightlies/herbie/egg-taylor/src/sandbox.rkt	72	6
run	/opt/racket-7.8/share/pkgs/profile-lib/main.rkt	39	2
profile-thunk	/opt/racket-7.8/share/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/opt/racket-7.8/collects/racket/engine.rkt	42	24

Reproduce

herbie shell --seed 2020271 
(FPCore (a b c)
  :name "jeff quadratic root 1"
  :precision binary64
  (if (>= b 0.0) (/ (- (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))) (* 2.0 a)) (/ (* 2.0 c) (+ (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))))))