Exception for Difference of squares

Specification

Math

\[\begin{array}{l} \\ a \cdot a - b \cdot b \end{array} \]

FPCore

(FPCore (a b) :precision binary64 (- (* a a) (* b b)))

C

double code(double a, double b) {
	return (a * a) - (b * b);
}

Fortran

real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = (a * a) - (b * b)
end function

Java

public static double code(double a, double b) {
	return (a * a) - (b * b);
}

Python

def code(a, b):
	return (a * a) - (b * b)

Julia

function code(a, b)
	return Float64(Float64(a * a) - Float64(b * b))
end

MATLAB

function tmp = code(a, b)
	tmp = (a * a) - (b * b);
end

Wolfram

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

Reproduce

herbie shell --seed 2024054 
(FPCore (a b)
  :name "Difference of squares"
  :precision binary64

  :alt
  (* (+ a b) (- a b))

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

Please file a bug report with this information.

Backtrace

precision: undefined; cannot use before initialization		L	C
ival-eval	/home/nightlies/herbie/longer-taylor/src/ground-truth.rkt	69	0
batch-prepare-points	/home/nightlies/herbie/longer-taylor/src/sampling.rkt	113	0
sample-points	/home/nightlies/herbie/longer-taylor/src/sampling.rkt	159	0
setup-context!	/home/nightlies/herbie/longer-taylor/src/mainloop.rkt	300	0
get-alternatives/report	/home/nightlies/herbie/longer-taylor/src/sandbox.rkt	169	0
(unnamed)	/home/nightlies/herbie/longer-taylor/src/sandbox.rkt	262	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