The bug is a mismatch between the optimizer and validator, where the optimizer can see that `string-append` is applied to a string and will definitely succeed, while the validator can't infer that behavior. The fact by itself isn't the problem, but it allows a further inference in the optimizer that's relevant to the validator.
The optimizer should use a specific flag internally at a specific point to keep it consistent with the validator. I'll push that repair after testing. At Wed, 18 Jan 2017 15:58:15 -0500, Leif Andersen wrote: > Hey all, > > I noticed that the following program fails to run, but only after its been > compiled (on 6.7, 6.6 and earlier don't seem to have this issue): > > https://gist.github.com/LeifAndersen/dfad9a8f55ef671e4f3aa41b321ef7bf > > #lang racket/base ;; ill-formed.rkt > (define ill > (let ((base (string-append "a"))) > (λ () base))) > (ill) > > To get the error, run: > > $ raco make ill-formed.rkt > $ racket ill-formed.rkt > ?? 0 > compiled/ill-formed_rkt.zo::369: read (compiled): ill-formed code > [../../../racket/gc2/../src/validate.c:1426] > context...: > standard-module-name-resolver > > This error doesn't seem to happen if `string-append` is replaced with > various other functions that create strings (or just string literals), and > it seems to go away if the function is inlined. > > I'm not entirely sure what's causing this bug yet, but it appears to either > be a bug in the versifier, or a new optimization. Has anyone else seen > something like this recently? (If not I'll update the list once I get a > sense as to what is going on.) > > ~Leif Andersen > > -- > You received this message because you are subscribed to the Google Groups > "Racket Users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to racket-users+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
