Crash when importing very complex closures.

[mveety]

To reproduce:

; import prompt
; . libraries/advanced_hooks.es
; set-prompt default
; conf -s advanced_hooks:prompt enable
; es
closure.c:121: assertion failed (k == nWord || k == nQword || k == nPrim || k == nThunk || k == nDict)
abort--core dumped

The closure in question (probably):

; echo $fn-%prompt
%closure(prompt-hooks='%dict(default => %closure(hostname=silverfox;username=mveety;redbold='^\ds^\e^'[31m'^\e^'[1m'^\de^';green='^\ds^\e^'[32m'^\de^';nocolor='^\ds^\e^'[0m'^\de^')@ * {prompt=''; '' ''''})';enabled=true)@ * {%seq {if {~ <={%count $prompt-hooks} 0} {return <={true}}} {for(hookname=<={sortlist <={dictnames $prompt-hooks}}){$prompt-hooks($hookname)}}}