Exception for Hyperbolic secant

Specification

\[\begin{array}{l} \\ \frac{2}{e^{x} + e^{-x}} \end{array} \]

(FPCore (x) :precision binary64 (/ 2.0 (+ (exp x) (exp (- x)))))

double code(double x) {
	return 2.0 / (exp(x) + exp(-x));
}

real(8) function code(x)
    real(8), intent (in) :: x
    code = 2.0d0 / (exp(x) + exp(-x))
end function

public static double code(double x) {
	return 2.0 / (Math.exp(x) + Math.exp(-x));
}

def code(x):
	return 2.0 / (math.exp(x) + math.exp(-x))

function code(x)
	return Float64(2.0 / Float64(exp(x) + exp(Float64(-x))))
end

function tmp = code(x)
	tmp = 2.0 / (exp(x) + exp(-x));
end

code[x_] := N[(2.0 / N[(N[Exp[x], $MachinePrecision] + N[Exp[(-x)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]

\begin{array}{l}

\\
\frac{2}{e^{x} + e^{-x}}
\end{array}

herbie shell --seed 2024238 
(FPCore (x)
  :name "Hyperbolic secant"
  :precision binary64
  (/ 2.0 (+ (exp x) (exp (- x)))))

Please file a bug report with this information.

error: contract violation expected: string? given: 'neg.f64		L	C
f345	.../match/compiler.rkt	559	40
loop	.../private/map.rkt	40	19
loop	.../private/map.rkt	40	19
compile-expr	/home/nightlies/herbie/bhargav-log-space/src/core/explain.rkt	70	0
explain	/home/nightlies/herbie/bhargav-log-space/src/core/explain.rkt	614	0
explain!	/home/nightlies/herbie/bhargav-log-space/src/core/mainloop.rkt	321	0
run-improve!	/home/nightlies/herbie/bhargav-log-space/src/core/mainloop.rkt	43	0
get-alternatives/report	/home/nightlies/herbie/bhargav-log-space/src/api/sandbox.rkt	184	0
(unnamed)	/home/nightlies/herbie/bhargav-log-space/src/api/sandbox.rkt	280	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