debugger invoked on a SYMBOL-PACKAGE-LOCKED-ERROR:
  Lock on package SB-DEBUG violated when defining VAR as a structure.
See also:
  The SBCL Manual, Node "Package Locks"

Type HELP for debugger help, or (SB-EXT:QUIT) to exit from SBCL.

restarts (invokable by number or by possibly-abbreviated name):
  0: [CONTINUE      ] Ignore the package lock.
  1: [IGNORE-ALL    ] Ignore all package locks in the context of this operation.
  2: [UNLOCK-PACKAGE] Unlock the package.
  3: [ABORT         ] Exit debugger, returning to top level.

(PACKAGE-LOCK-VIOLATION #<PACKAGE "SB-DEBUG">)