hush: BUG in varexp2 when doing a=${a:+$a }a

[Aleksander Mazur]

Hi,

hush aborts when doing mentioned parameter substitution.
(Fortunately it works fine when double-quoted.)

$ ./hush


BusyBox v1.37.0.git (2023-06-04 12:42:18 CEST) hush - the humble shell
Enter 'help' for a list of built-in commands.

/tmp $ a=${a:+$a }a
/tmp $ echo $a
a
/tmp $ a=${a:+$a }a
hush: BUG in varexp2
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