\[\frac{-\left(f + n\right)}{f - n}\]

\frac{-\left(f + n\right)}{f - n}

double f(double f, double n) {
        double r24614 = f;
        double r24615 = n;
        double r24616 = r24614 + r24615;
        double r24617 = -r24616;
        double r24618 = r24614 - r24615;
        double r24619 = r24617 / r24618;
        return r24619;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019323 
(FPCore (f n)
  :name "subtraction fraction"
  :precision binary64
  (/ (- (+ f n)) (- f n)))

Backtrace

get-representation: Unknown representation real		L	C
(unnamed)	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/core/regimes.rkt	65	3
filter	/opt/racket-7.2/collects/racket/private/list.rkt	256	2
infer-splitpoints	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/core/regimes.rkt	34	0
get-final-combination	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/mainloop.rkt	369	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