Вызвать дебаггер в определённом месте

(break "You have entered the debugger with arguments: ~s" '(1 2 3))

You have entered the debugger with arguments: (1 2 3)

[Condition of type SIMPLE-CONDITION]

Restarts:
0: [CONTINUE] Return from BREAK loop
1: [ABORT-REQUEST] Abort handling SLIME request.
2: [ABORT] Return to SLIME top-level.
3: [ABORT] ABORT