compiler-free-reference-warning

This style warning is signaled when the compiler sees a variable it does not recognize (and thus treats as a special variable). This case has always been warned about, but in releases prior to 10.0, it was a simple warning.

cl-user(12): (setq *break-on-signals* t)
t
cl-user(13): (defun foo () (+ x 10))
foo
cl-user(14): (compile 'foo)
; While compiling #'foo at top level:
Break: Free reference to undeclared variable x assumed special.
break entered because of *break-on-signals*.

Restart actions (select using :continue):
 0: return from break.
 1: skip warning.
 2: continue processing.
 3: Return to Top Level (an "abort" restart).
 4: Abort entirely from this (lisp) process.
[1c] cl-user(15): :zo
Evaluation stack:

   (break "~a~%break entered because of *break-on-signals*."
          #<compiler-free-reference-warning @ #x20d52a52>)
 ->(signal #<compiler-free-reference-warning @ #x20d52a52>)
   (warn compiler-free-reference-warning :format-control ...)

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This page is new in the 10.0 release.
Created 2019.8.20.