bug#59984: segfault in list-ref

Hi guile dev team

Here's a glaring segfault in guile 3.0.8

GNU Guile 3.0.8
Copyright (C) 1995-2021 Free Software Foundation, Inc.

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This program is free software, and you are welcome to redistribute it
under certain conditions; type `,show c' for details.

Enter `,help' for help.
scheme@(guile-user)>
scheme@(guile-user)> (define lst (iota 20))
scheme@(guile-user)> (list-ref lst 1)
$1 = 1
scheme@(guile-user)> (list-ref lst 1.5)
ice-9/boot-9.scm:1685:16: In procedure raise-exception:
Wrong type (expecting exact integer): 1.5

Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
scheme@(guile-user) [1]>

scheme@(guile-user)> (list-ref lst -1)
Segmentation fault (core dumped)