Exception for Ian Simplification

Specification

\[\begin{array}{l} \\ \frac{\mathsf{PI}\left(\right)}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right) \end{array} \]

(FPCore (x)
 :precision binary64
 (- (/ (PI) 2.0) (* 2.0 (asin (sqrt (/ (- 1.0 x) 2.0))))))

\begin{array}{l}

\\
\frac{\mathsf{PI}\left(\right)}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)
\end{array}

Reproduce

herbie shell --seed 2024288 
(FPCore (x)
  :name "Ian Simplification"
  :precision binary64

  :alt
  (! :herbie-platform default (asin x))

  (- (/ (PI) 2.0) (* 2.0 (asin (sqrt (/ (- 1.0 x) 2.0))))))

Please file a bug report with this information.

Backtrace

error: contract violation expected: string? given: 'asin.f64		L	C
f407	.../match/compiler.rkt	559	40
loop	.../private/map.rkt	40	19
loop	.../private/map.rkt	40	19
loop	.../private/map.rkt	40	19
loop	.../private/map.rkt	40	19
loop	.../private/map.rkt	40	19
loop	.../private/map.rkt	40	19
loop	.../private/map.rkt	40	19
compile-expr	/home/nightlies/herbie/bhargav-log-space/src/core/explain.rkt	84	0
explain	/home/nightlies/herbie/bhargav-log-space/src/core/explain.rkt	713	0
explain!	/home/nightlies/herbie/bhargav-log-space/src/core/mainloop.rkt	323	0
run-improve!	/home/nightlies/herbie/bhargav-log-space/src/core/mainloop.rkt	45	0
get-alternatives/report	/home/nightlies/herbie/bhargav-log-space/src/api/sandbox.rkt	186	0
(unnamed)	/home/nightlies/herbie/bhargav-log-space/src/api/sandbox.rkt	282	6
(unnamed)	/usr/share/racket/pkgs/profile-lib/main.rkt	40	10
profile-thunk	/usr/share/racket/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/usr/share/racket/collects/racket/engine.rkt	42	24