I got this error message under the latest AquaMacs:

This is a bug in Slime itself. Please report this to the mailinglist slime-devel@common-lisp.net and include your Emacs version, the guilty Lisp source file, the header of this message, and the following backtrace.

Backtrace: %s -------------------------------------------------------------- " (buffer-name) (line-number-at-pos) (current-column) (point) (apply (function format) message args) (with-output-to-string (backtrace))) slime-bug("Caught error when trying to extend the region for fontification. The error was: %S Further: font-lock-beg=%d, font-lock-end=%d." (error "Invalid search bound (wrong side of point)") 10586 11099) slime-extend-region-for-font-lock() font-lock-default-fontify-region(10586 11099 nil) font-lock-fontify-region(10586 11099) run-hook-with-args(font-lock-fontify-region 10586 11099) byte-code("\302\303 #\207" [start next run-hook-with-args jit-lock- functions] 4) jit-lock-fontify-now(10586 11086) jit-lock-function(10586)

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Sorry, can't share the code, but it was in a format expression.

Regards,

Patrick