\[\frac{x + 1}{1 - x}\]

\frac{x + 1}{1 - x}

double f(double x) {
        double r8294 = x;
        double r8295 = 1.0;
        double r8296 = r8294 + r8295;
        double r8297 = r8295 - r8294;
        double r8298 = r8296 / r8297;
        return r8298;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019305 
(FPCore (x)
  :name "Prelude:atanh from fay-base-0.20.0.1"
  :precision binary64
  (/ (+ x 1) (- 1 x)))

Backtrace

exact?: contract violation expected: number? given: 'h0		L	C
egg-parsed->expr	/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/eggmath.rkt	65	0
for-loop	/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/eggmath.rkt	70	6
egg-parsed->expr	/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/eggmath.rkt	65	0
for-loop	/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/eggmath.rkt	70	6
egg-parsed->expr	/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/eggmath.rkt	65	0
(unnamed)	/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/simplify.rkt	49	8
egraph-add-exprs	/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/eggmath.rkt	122	0
egraph-run	/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/eggmath.rkt	55	0
(unnamed)	/data/pavpan/nightlies/herbie/eggmath-testversion/src/core/simplify.rkt	38	0
simplify!	/data/pavpan/nightlies/herbie/eggmath-testversion/src/mainloop.rkt	223	0
run-improve47	/data/pavpan/nightlies/herbie/eggmath-testversion/src/mainloop.rkt	345	0
(unnamed)	/opt/racket-7.2/collects/racket/private/more-scheme.rkt	261	28
run	/opt/racket-7.2/share/pkgs/profile-lib/main.rkt	39	2
profile-thunk16	/opt/racket-7.2/share/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/opt/racket-7.2/collects/racket/private/more-scheme.rkt	261	28