Radioactive exchange between two surfaces

Specification

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\[\begin{array}{l} \\ {x}^{4} - {y}^{4} \end{array} \]
(FPCore (x y) :precision binary64 (- (pow x 4.0) (pow y 4.0)))
double code(double x, double y) {
	return pow(x, 4.0) - pow(y, 4.0);
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    code = (x ** 4.0d0) - (y ** 4.0d0)
end function
public static double code(double x, double y) {
	return Math.pow(x, 4.0) - Math.pow(y, 4.0);
}
def code(x, y):
	return math.pow(x, 4.0) - math.pow(y, 4.0)
function code(x, y)
	return Float64((x ^ 4.0) - (y ^ 4.0))
end
function tmp = code(x, y)
	tmp = (x ^ 4.0) - (y ^ 4.0);
end
code[x_, y_] := N[(N[Power[x, 4.0], $MachinePrecision] - N[Power[y, 4.0], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
{x}^{4} - {y}^{4}
\end{array}

Reproduce

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herbie shell --seed 2024246 
(FPCore (x y)
  :name "Radioactive exchange between two surfaces"
  :precision binary64
  (- (pow x 4.0) (pow y 4.0)))

Please file a bug report with this information.

Backtrace

map: contract violation expected: list? given: '((-.f64 (pow.f64 x #s(literal 4 binary64)) (pow.f64 y #s(literal 4 binary64))) . #hasheq((errs . (1 1 1 1 1 1 1 1 1 2251799813685249 1 1 18439988674268495873 1 1 18439988674268495873 1 1 1 1 1 1 1 1 1 18439988674268495873 1 1 1 1 1 1 1 1 22517998136852...LC
gen-map/usr/local/racket/collects/racket/private/map.rkt2572
actual-errors/home/nightlies/herbie/zane-concrete-values/src/core/explain.rkt350
generate-timelines/home/nightlies/herbie/zane-concrete-values/src/core/explain.rkt4930
explain!/home/nightlies/herbie/zane-concrete-values/src/core/mainloop.rkt3220
run-improve!/home/nightlies/herbie/zane-concrete-values/src/core/mainloop.rkt440
get-alternatives/report/home/nightlies/herbie/zane-concrete-values/src/api/sandbox.rkt1860
(unnamed)/home/nightlies/herbie/zane-concrete-values/src/api/sandbox.rkt2826
(unnamed)/usr/local/racket/share/pkgs/profile-lib/main.rkt4010
profile-thunk/usr/local/racket/share/pkgs/profile-lib/main.rkt90
(unnamed)/usr/local/racket/collects/racket/engine.rkt4224