Failed aver (NOT (MEMQ PUSH END-STACK))

[Eric Marsden]

* (lisp-implementation-version)
"1.0.35.6"
* (LAMBDA (A)
  (BLOCK B1
    (MULTIPLE-VALUE-PROG1 42
      (CATCH 'CT1
        (RETURN-FROM B1
          (CATCH 'CT2
            (MIN 1 a)))))))

debugger invoked on a SB-INT:BUG in thread #<THREAD "initial thread" RUNNING {AA07749}>:
    failed AVER: (NOT (MEMQ PUSH END-STACK))

On Linux/x86.

[Nikodemus Siivola (nikodemus)]

Huh, I could have sworn we had an example of this on Launchpad already.

The problem is AFAIK that stack analysis is confused by unreachable code left in the component: because control-analysis isn't sufficiently aggressive re. functions in the component that are never called, particularly cleanups.

[Roman Marynchak (roman-marynchak)]

This bug is the close friend of 'nonlinear LVARs (aka MISC.293)' https://bugs.launchpad.net/sbcl/+bug/309099

The reproduction code is very similar in both cases, as well as the cleanup issues involved during the stack analysis.