Numeric.SpecFunctions:stirlingError from math-functions-0.1.5.2

?

\[\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z \]
(FPCore (x y z) :precision binary64 (- (+ (- x (* (+ y 0.5) (log y))) y) z))
double code(double x, double y, double z) {
	return ((x - ((y + 0.5) * log(y))) + y) - z;
}
real(8) function code(x, y, z)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    code = ((x - ((y + 0.5d0) * log(y))) + y) - z
end function
public static double code(double x, double y, double z) {
	return ((x - ((y + 0.5) * Math.log(y))) + y) - z;
}
def code(x, y, z):
	return ((x - ((y + 0.5) * math.log(y))) + y) - z
function code(x, y, z)
	return Float64(Float64(Float64(x - Float64(Float64(y + 0.5) * log(y))) + y) - z)
end
function tmp = code(x, y, z)
	tmp = ((x - ((y + 0.5) * log(y))) + y) - z;
end
code[x_, y_, z_] := N[(N[(N[(x - N[(N[(y + 0.5), $MachinePrecision] * N[Log[y], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + y), $MachinePrecision] - z), $MachinePrecision]
\left(\left(x - \left(y + 0.5\right) \cdot \log y\right) + y\right) - z

Reproduce?

Please include this information when filing a bug report:

herbie shell --seed 2023243 
(FPCore (x y z)
  :name "Numeric.SpecFunctions:stirlingError from math-functions-0.1.5.2"
  :precision binary64

  :herbie-target
  (- (- (+ y x) z) (* (+ y 0.5) (log y)))

  (- (+ (- x (* (+ y 0.5) (log y))) y) z))

Backtrace

_arb-ptr: contract violation expected: _arb? given: '(ival-illegal)LC
_arb-ptrunknown
arb->ival/home/nightlies/herbie/arb-support/src/arb.rkt1600
search-step/home/nightlies/herbie/arb-support/src/searchreals.rkt370
find-intervals/home/nightlies/herbie/arb-support/src/searchreals.rkt870
make-sampler/home/nightlies/herbie/arb-support/src/sampling.rkt940
sample-points/home/nightlies/herbie/arb-support/src/ground-truth.rkt640
setup-context!/home/nightlies/herbie/arb-support/src/mainloop.rkt2930
get-alternatives/report/home/nightlies/herbie/arb-support/src/sandbox.rkt1480
(unnamed)/home/nightlies/herbie/arb-support/src/sandbox.rkt2476
(unnamed)/usr/share/racket/pkgs/profile-lib/main.rkt4010
profile-thunk/usr/share/racket/pkgs/profile-lib/main.rkt90
(unnamed)/usr/share/racket/collects/racket/engine.rkt4224