Difference of squares

Specification

?
\[\begin{array}{l} \\ a \cdot a - b \cdot b \end{array} \]
(FPCore (a b) :precision binary64 (- (* a a) (* b b)))
double code(double a, double b) {
	return (a * a) - (b * b);
}
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = (a * a) - (b * b)
end function
public static double code(double a, double b) {
	return (a * a) - (b * b);
}
def code(a, b):
	return (a * a) - (b * b)
function code(a, b)
	return Float64(Float64(a * a) - Float64(b * b))
end
function tmp = code(a, b)
	tmp = (a * a) - (b * b);
end
code[a_, b_] := N[(N[(a * a), $MachinePrecision] - N[(b * b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
a \cdot a - b \cdot b
\end{array}

Reproduce

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herbie shell --seed 2024005 
(FPCore (a b)
  :name "Difference of squares"
  :precision binary64

  :herbie-target
  (* (+ a b) (- a b))

  (- (* a a) (* b b)))

Please file a bug report with this information.

Backtrace

repr->cost: arity mismatch; the expected number of arguments does not match the given number expected: 2 given: 1LC
loop.../private/map.rkt5419
f490.../match/compiler.rkt54840
loop.../private/map.rkt5419
f490.../match/compiler.rkt54840
make-alt-table/home/nightlies/herbie/platforms/src/core/alt-table.rkt400
(unnamed)/usr/share/racket/collects/racket/contract/private/arrow-val-first.rkt48618
initialize-alt-table!/home/nightlies/herbie/platforms/src/mainloop.rkt3160
mutate!/home/nightlies/herbie/platforms/src/mainloop.rkt3520
run-improve!/home/nightlies/herbie/platforms/src/mainloop.rkt3380
get-alternatives/report/home/nightlies/herbie/platforms/src/sandbox.rkt1690
(unnamed)/home/nightlies/herbie/platforms/src/sandbox.rkt2626
(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