fresh_temp takes the purpose, so and/or mint and~N and or~N where they used to
mint destructure~N. The names are shown -- the inspector lists a frame locals
by name -- and nothing pinned the old spelling; destructure~nth is an
unrelated compiler builtin. Confirmed in a --debug build DWARF.
The caret wart on and last operand in a want-free position is documented at
the site and in FIX.org rather than fixed: every candidate fix reads worse
than what is there, and the real fix is check_if choosing which arm to blame.