Consider mutations as borrows in generator drop tracking #94068
Merged
Conversation
This file contains 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
rustbot
added
the
T-compiler
rust-highfive
added
the
S-waiting-on-review
This comment has been minimized.
This comment has been minimized.
This is needed to match MIR more conservative approximation of any borrowed value being live across a suspend point (See rust-lang#94067). This change considers an expression such as `x.y = z` to be a borrow of `x` and therefore keeps `x` live across suspend points.
eholk
force-pushed
the
drop-track-field-assign
branch
from
3e02534
to
074d757
Compare
|
@bors r+ rollup |
|
📌 Commit 074d757 has been approved by |
bors
added
S-waiting-on-bors
bors
added a commit
to rust-lang-ci/rust
that referenced
this pull request
Feb 25, 2022
…askrgr Rollup of 6 pull requests Successful merges: - rust-lang#92714 (Provide ignore message in the result of test) - rust-lang#93273 (Always check cg_llvm with ./x.py check) - rust-lang#94068 (Consider mutations as borrows in generator drop tracking) - rust-lang#94184 (BTree: simplify test code) - rust-lang#94297 (update const_generics_defaults release notes) - rust-lang#94341 (Remove a duplicate space) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup
Dylan-DPC
added a commit
to Dylan-DPC/rust
that referenced
this pull request
Mar 5, 2022
… r=tmiasko Reenable generator drop tracking tests and fix mutation handling The previous PR, rust-lang#94068, was overly zealous in counting mutations as borrows, which effectively nullified drop tracking. We would have caught this except the drop tracking tests were still ignored, despite having the option of using the `-Zdrop-tracking` flag now. This PR fixes the issue introduced by rust-lang#94068 by only counting mutations as borrows the mutated place has a project. This is sufficient to distinguish `x.y = 42` (which should count as a borrow of `x`) from `x = 42` (which is not a borrow of `x` because the whole variable is overwritten). This PR also re-enables the drop tracking regression tests using the `-Zdrop-tracking` flag so we will avoid introducing these sorts of issues in the future. Thanks to `@tmiasko` for noticing this problem and pointing it out! r? `@tmiasko`
Dylan-DPC
added a commit
to Dylan-DPC/rust
that referenced
this pull request
Mar 5, 2022
… r=tmiasko Reenable generator drop tracking tests and fix mutation handling The previous PR, rust-lang#94068, was overly zealous in counting mutations as borrows, which effectively nullified drop tracking. We would have caught this except the drop tracking tests were still ignored, despite having the option of using the `-Zdrop-tracking` flag now. This PR fixes the issue introduced by rust-lang#94068 by only counting mutations as borrows the mutated place has a project. This is sufficient to distinguish `x.y = 42` (which should count as a borrow of `x`) from `x = 42` (which is not a borrow of `x` because the whole variable is overwritten). This PR also re-enables the drop tracking regression tests using the `-Zdrop-tracking` flag so we will avoid introducing these sorts of issues in the future. Thanks to ``@tmiasko`` for noticing this problem and pointing it out! r? ``@tmiasko``
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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.
This is needed to match MIR more conservative approximation of any borrowed value being live across a suspend point (See #94067). This change considers an expression such as
x.y = zto be a borrow ofxand therefore keepsxlive across suspend points.r? @nikomatsakis