Exception for Language.Haskell.HsColour.ColourHighlight:unbase from hscolour-1.23

Math

\[\left(x \cdot y + z\right) \cdot y + t\]

C

double f(double x, double y, double z, double t) {
        double r8510 = x;
        double r8511 = y;
        double r8512 = r8510 * r8511;
        double r8513 = z;
        double r8514 = r8512 + r8513;
        double r8515 = r8514 * r8511;
        double r8516 = t;
        double r8517 = r8515 + r8516;
        return r8517;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019194 
(FPCore (x y z t)
  :name "Language.Haskell.HsColour.ColourHighlight:unbase from hscolour-1.23"
  (+ (* (+ (* x y) z) y) t))

Backtrace

result arity mismatch; expected number of values not received expected: 2 received: 1 in: local-binding form values...: 0		L	C
loop	/data/pavpan/nightlies/herbie/various-cleanup/src/core/extraction.rkt	25	2
(unnamed)	/data/pavpan/nightlies/herbie/various-cleanup/src/core/simplify.rkt	26	0
simplify!	/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt	220	0
run-improve47	/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt	342	0
(unnamed)	/opt/racket-7.0/collects/racket/private/more-scheme.rkt	261	28
run	/opt/racket-7.0/share/pkgs/profile-lib/main.rkt	39	2
profile-thunk16	/opt/racket-7.0/share/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/opt/racket-7.0/collects/racket/private/more-scheme.rkt	261	28