-115:
- reported by Martin Atzmueller 2001-06-25; originally from CMU CL bugs
- collection:
- (in-package :cl-user)
- ;;; The following invokes a compiler error.
- (declaim (optimize (speed 2) (debug 3)))
- (defun tst ()
- (flet ((m1 ()
- (unwind-protect nil)))
- (if (catch nil)
- (m1)
- (m1))))
- The error message in sbcl-0.6.12.42 is
- internal error, failed AVER:
- "(COMMON-LISP:EQ (SB!C::TN-ENVIRONMENT SB!C:TN) SB!C::TN-ENV)"
-
- This examples better illustrates the problem:
-
- (defun tst ()
- (declare (optimize (speed 2) (debug 3)))
- (flet ((m1 ()
- (bar (if (foo) 1 2))
- (let ((x (foo)))
- (bar x (list x)))))
- (if (catch nil)
- (m1)
- (m1))))
-
- (X is allocated in the physical environment of M1; X is :WRITE in
- the call of LET [convert-to-global]; IF makes sure that a block
- exists in M1 before this call.)
-
- Because X is :DEBUG-ENVIRONMENT, it is :LIVE by default in all
- blocks in the environment, particularly it is :LIVE in the start of
- M1 (where it is not yet :WRITE) [setup-environment-tn-conflicts].
-
- Then :LIVE is propagated backwards, i.e. into the caller of M1
- where X does not exist [lifetime-flow-analysis].
-
- (CATCH NIL) causes all TNs to be saved; Python fails on saving
- non-existent variable; if it is replaced with (FOO), the problem
- appears when debugging TST: LIST-LOCALS says
-
- debugger invoked on condition of type SB-DI:UNKNOWN-DEBUG-VAR:
-
- #<SB-DI::COMPILED-DEBUG-VAR X 0
- {905FF7D}> is not in #<SB-DI::COMPILED-DEBUG-FUNCTION TST>.
-
- (in those old versions, in which debugger worked :-().
-