Here's the minimal test case to tickle the `)IN crashes` bug:
---- file: foo.apl ----
⍝!
'lib_file_io' ⎕fx 'pkg⍙fileio'
---- end file ----
In GNU APL:
)load foo
loading )DUMP file /home/dlamkins/APL/workspaces/foo.apl...
WAS CLEAR WS
pkg⍙fileio
)out foo
)in foo
DOMAIN ERROR+
immediate_execution() caught APL error 0x50004 (DOMAIN ERROR)
====================================================
SEGMENTATION FAULT
----------------------------------------
-- Stack trace at main.cc:121
----------------------------------------
0x7f79b8733d65 __libc_start_main
0x435645 main
0x5294ba Workspace::immediate_execution(bool)
0x5009ae TestFiles::apl_error(char const*)
0x7f79ba404750
0x4859aa
========================================
====================================================
Process apl exited abnormally with code 3
