Backport pr 31442 to beta: Split dummy-idx node to fix expand_givens DFS#31768
Merged
Conversation
…odes. Why do this: The RegionGraph representation previously conflated all of the non-variable regions (i.e. the concrete regions such as lifetime parameters to the current function) into a single dummy node. A single dummy node leads DFS on a graph `'a -> '_#1 -> '_#0 -> 'b` to claim that `'_#1` is reachable from `'_#0` (due to `'a` and `'b` being conflated in the graph representation), which is incorrect (and can lead to soundness bugs later on in compilation, see rust-lang#30438). Splitting the dummy node ensures that DFS will never introduce new ancestor relationships between nodes for variable regions in the graph.
alexcrichton
added a commit
that referenced
this pull request
Feb 19, 2016
Backport pr 31442 to beta: Split dummy-idx node to fix expand_givens DFS
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Backport pr #31442 to beta