Exception for fabs fraction 2

Specification

\[\begin{array}{l} \\ \frac{\left|a - b\right|}{2} \end{array} \]

(FPCore (a b) :precision binary64 (/ (fabs (- a b)) 2.0))

double code(double a, double b) {
	return fabs((a - b)) / 2.0;
}

real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = abs((a - b)) / 2.0d0
end function

public static double code(double a, double b) {
	return Math.abs((a - b)) / 2.0;
}

def code(a, b):
	return math.fabs((a - b)) / 2.0

function code(a, b)
	return Float64(abs(Float64(a - b)) / 2.0)
end

function tmp = code(a, b)
	tmp = abs((a - b)) / 2.0;
end

code[a_, b_] := N[(N[Abs[N[(a - b), $MachinePrecision]], $MachinePrecision] / 2.0), $MachinePrecision]

\begin{array}{l}

\\
\frac{\left|a - b\right|}{2}
\end{array}

herbie shell --seed 2024246 
(FPCore (a b)
  :name "fabs fraction 2"
  :precision binary64
  (/ (fabs (- a b)) 2.0))

Please file a bug report with this information.

map: contract violation expected: list? given: '(b . #hasheq((errs . (1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ...		L	C
gen-map	/usr/local/racket/collects/racket/private/map.rkt	257	2
actual-errors	/home/nightlies/herbie/zane-concrete-values/src/core/explain.rkt	35	0
generate-timelines	/home/nightlies/herbie/zane-concrete-values/src/core/explain.rkt	493	0
explain!	/home/nightlies/herbie/zane-concrete-values/src/core/mainloop.rkt	322	0
run-improve!	/home/nightlies/herbie/zane-concrete-values/src/core/mainloop.rkt	44	0
get-alternatives/report	/home/nightlies/herbie/zane-concrete-values/src/api/sandbox.rkt	186	0
(unnamed)	/home/nightlies/herbie/zane-concrete-values/src/api/sandbox.rkt	282	6
(unnamed)	/usr/local/racket/share/pkgs/profile-lib/main.rkt	40	10
profile-thunk	/usr/local/racket/share/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/usr/local/racket/collects/racket/engine.rkt	42	24