Updated to not treat void_node the same way. All other changes from v1 are adjusting comments to that effect. All tests run against the same baseline as the previous patch, no regressions.
On Sat, Sep 19, 2026 at 7:05 PM Joshua Berne <[email protected]> wrote: > My reasoning was that in a guarded situation where we are using this > modifiable_tracker I couldn't think of a reason *not* to allow it to reuse > external storage where the object in that storage has been destroyed. > > I also couldn't think of a case that would validly hit that branch, so i'm > fine either way. I'll get a v2 that skips void_node out next, and i'll add > a comment indicating that the skipping is intentional. > > On Sat, Sep 19, 2026 at 5:43 PM Jason Merrill <[email protected]> wrote: > >> On 9/18/26 7:21 PM, Joshua Berne wrote: >> > Attached is a patch fixing a bug that occurs when a contract assertion >> > during constant evaluation invokes a function that has already been >> > invoked (outside the contract assertion) during that constant >> evaluation >> > --- the already-destroyed result object for the function looks like an >> > attempt to modify code outside the function to the contract assertion >> > evaluation. >> > >> > A similar code path could probably be constructed where an [[assume]] >> > would be discarded, which is very hard to observe but should also be >> > smoothed out by this patch. >> >> > This change updates the put_value member of constexpr_global_ctx to >> recognize >> > void_list_node values in the map as not being a concern for what >> modifiables >> > is tracking, and treats them the same way it treats not yet having a >> value in >> > the map for that key. >> >> Agreed, those cases can be treated as equivalent. >> >> > void_node is treated the same way if it is found in >> > the map to be consistent with other handling of the values that are >> stored, >> > though no case seems to currently hit that path. >> >> Let's not treat void_node the same way; that indicates an object still >> within its storage duration. >> >> Jason >> >>
v2-0001-c-contracts-assertion-predicate-re-invoking-const.patch
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