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Resolver: (un)tracked borrows for CmRefCell made safe by unsafe speculative flag - #160510

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LorrensP-2158466:res-unsafe-speculative-flag
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Resolver: (un)tracked borrows for CmRefCell made safe by unsafe speculative flag#160510
LorrensP-2158466 wants to merge 1 commit into
rust-lang:mainfrom
LorrensP-2158466:res-unsafe-speculative-flag

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@LorrensP-2158466

@LorrensP-2158466 LorrensP-2158466 commented Aug 4, 2026

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Implements the tracked/untracked borrowing of CmRefCell such that we do not mutate any state during speculative resolution. Made safe by an unsafe field that requires any borrows to be dropped before the flag can change.

r? @petrochenkov

@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Aug 4, 2026
petrochenkov
petrochenkov reviewed Aug 4, 2026
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Comment thread compiler/rustc_resolve/src/imports.rs
Comment thread compiler/rustc_resolve/src/lib.rs Outdated
Comment thread compiler/rustc_resolve/src/lib.rs Outdated
Comment thread compiler/rustc_resolve/src/lib.rs Outdated
Comment thread compiler/rustc_resolve/src/lib.rs Outdated
@petrochenkov

petrochenkov commented Aug 4, 2026

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We already benchmarked this as a regression (due to returning CmRef from borrow and resolution), but we know that #160345 recovers most of the performance, so we can merge this separately.

@petrochenkov petrochenkov added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Aug 4, 2026
@LorrensP-2158466

LorrensP-2158466 commented Aug 4, 2026

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Unfortunately, we can't "tie" the borrow of the resolver to the CmRef because it conflicts to much. Sometimes we only require a borrow of a CmRefCell but still want to mutate the resolver it self in some way.

@petrochenkov

petrochenkov commented Aug 4, 2026

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Unfortunately, we can't "tie" the borrow of the resolver to the CmRef because it conflicts to much. Sometimes we only require a borrow of a CmRefCell but still want to mutate the resolver it self in some way.

Yeah, I expected it to be very inconvenient.

@LorrensP-2158466
implement unsafe speculative flag to be used by CmRefCell::borrow, …
e0830fa 
…which does tracked and untracked borrowing
@LorrensP-2158466
LorrensP-2158466 force-pushed the res-unsafe-speculative-flag branch from 17802e1 to e0830fa Compare August 4, 2026 15:44
@LorrensP-2158466

LorrensP-2158466 commented Aug 4, 2026

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force-pushed to keep it at one commit, @rustbot ready.

@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Aug 4, 2026
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petrochenkov commented Aug 4, 2026

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@bors r+

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rust-bors Bot commented Aug 4, 2026

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📌 Commit e0830fa has been approved by petrochenkov

It is now in the queue for this repository.

🌲 The tree is currently closed for pull requests below priority 10. This pull request will be tested once the tree is reopened.

Reason for tree closure: manually handling queue due to backlog

@rust-bors rust-bors Bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Aug 4, 2026
JonathanBrouwer added a commit to JonathanBrouwer/rust that referenced this pull request Aug 5, 2026
@JonathanBrouwer
Rollup merge of rust-lang#160510 - LorrensP-2158466:res-unsafe-specul…
c4fbf66 
…ative-flag, r=petrochenkov

Resolver: (un)tracked borrows for `CmRefCell` made safe my unsafe speculative flag

Implements the tracked/untracked borrowing of `CmRefCell` such that we do not mutate *any* state during speculative resolution. Made safe by an unsafe field that requires any borrows to be dropped before the flag can change.

r? @petrochenkov
@JonathanBrouwer JonathanBrouwer mentioned this pull request Aug 5, 2026
Closed
jhpratt added a commit to jhpratt/rust that referenced this pull request Aug 5, 2026
@jhpratt
Rollup merge of rust-lang#160510 - LorrensP-2158466:res-unsafe-specul…
5703cb8 
…ative-flag, r=petrochenkov

Resolver: (un)tracked borrows for `CmRefCell` made safe my unsafe speculative flag

Implements the tracked/untracked borrowing of `CmRefCell` such that we do not mutate *any* state during speculative resolution. Made safe by an unsafe field that requires any borrows to be dropped before the flag can change.

r? @petrochenkov
@jhpratt jhpratt mentioned this pull request Aug 5, 2026
Closed
JonathanBrouwer added a commit to JonathanBrouwer/rust that referenced this pull request Aug 5, 2026
@JonathanBrouwer
Rollup merge of rust-lang#160510 - LorrensP-2158466:res-unsafe-specul…
bd03891 
…ative-flag, r=petrochenkov

Resolver: (un)tracked borrows for `CmRefCell` made safe my unsafe speculative flag

Implements the tracked/untracked borrowing of `CmRefCell` such that we do not mutate *any* state during speculative resolution. Made safe by an unsafe field that requires any borrows to be dropped before the flag can change.

r? @petrochenkov
@JonathanBrouwer JonathanBrouwer mentioned this pull request Aug 5, 2026
Closed
rust-bors Bot pushed a commit that referenced this pull request Aug 5, 2026
@bors
Auto merge of #160554 - JonathanBrouwer:rollup-clq6Y1g, r=JonathanBro…
6eefd8c 
…uwer

Rollup of 22 pull requests

Successful merges:

 - #158147 (std: fix stack buffer overflow in Windows junction_point)
 - #159784 (Hint that memchr returns an in-bounds index)
 - #160130 (Select cache values to verify by key fingerprint, not value fingerprint)
 - #160343 (Rename `OutlivesPredicate` to `OutlivesClause`)
 - #160360 (Remove rustc_middle dependency on rustc_hir_pretty)
 - #160387 (rustc_codegen_ssa: Correctly apply the static `--jobs-backend` limit to backend parallelism)
 - #160422 (move mir-opt miri tests to CI logic)
 - #160444 (Avoid resolving path keywords outside `TypeNS`)
 - #160510 (Resolver: (un)tracked borrows for `CmRefCell` made safe my unsafe speculative flag)
 - #155424 ([blocked] Link to proposed LLM policy in CONTRIBUTING and pull request template)
 - #158726 (std: move futex implementations into sys::sync::futex)
 - #159225 (Split IncrCompSession out of Session)
 - #159820 (Make the `rustc_unsafe_specialization_marker` attribute actually `unsafe`)
 - #160198 (Rework `smallest_range_containing` to handle duplicates)
 - #160362 (Split `SpannedTypeVisitor` into its own crate, `rustc_ty_walk`)
 - #160390 (autodiff: Handle slice-tailed DSTs in type trees)
 - #160420 (Suggest `cast_signed()` for overflowing signed integer literals)
 - #160520 (Add some tests for specialization)
 - #160522 (fix(bootstrap): Normalize the names of proc macro dependency crates)
 - #160531 (docs: fix typo in AllowExprMetavar comment)
 - #160538 (Update expect messages in tcp.rs doc examples to follow the style guide)
 - #160548 (bootstrap: Register `coverage-map` and `coverage-run` aliases via a separate step)
JonathanBrouwer added a commit to JonathanBrouwer/rust that referenced this pull request Aug 5, 2026
@JonathanBrouwer
Rollup merge of rust-lang#160510 - LorrensP-2158466:res-unsafe-specul…
cdfc8c3 
…ative-flag, r=petrochenkov

Resolver: (un)tracked borrows for `CmRefCell` made safe my unsafe speculative flag

Implements the tracked/untracked borrowing of `CmRefCell` such that we do not mutate *any* state during speculative resolution. Made safe by an unsafe field that requires any borrows to be dropped before the flag can change.

r? @petrochenkov
@JonathanBrouwer JonathanBrouwer mentioned this pull request Aug 5, 2026
Closed
@LorrensP-2158466 LorrensP-2158466 changed the title Resolver: (un)tracked borrows for CmRefCell made safe my unsafe speculative flag Resolver: (un)tracked borrows for CmRefCell made safe by unsafe speculative flag Aug 5, 2026
rust-bors Bot pushed a commit that referenced this pull request Aug 5, 2026
@bors
Auto merge of #160557 - JonathanBrouwer:rollup-OtzfGt5, r=JonathanBro…
94031e1 
…uwer

Rollup of 25 pull requests

Successful merges:

 - #154585 (treat no_mangle_generic_items as hard error instead of lint warning)
 - #158147 (std: fix stack buffer overflow in Windows junction_point)
 - #160130 (Select cache values to verify by key fingerprint, not value fingerprint)
 - #160343 (Rename `OutlivesPredicate` to `OutlivesClause`)
 - #160360 (Remove rustc_middle dependency on rustc_hir_pretty)
 - #160387 (rustc_codegen_ssa: Correctly apply the static `--jobs-backend` limit to backend parallelism)
 - #160422 (move mir-opt miri tests to CI logic)
 - #160444 (Avoid resolving path keywords outside `TypeNS`)
 - #160510 (Resolver: (un)tracked borrows for `CmRefCell` made safe my unsafe speculative flag)
 - #155424 ([blocked] Link to proposed LLM policy in CONTRIBUTING and pull request template)
 - #158726 (std: move futex implementations into sys::sync::futex)
 - #158762 (Emit thumb code on VEX V5)
 - #159225 (Split IncrCompSession out of Session)
 - #159820 (Make the `rustc_unsafe_specialization_marker` attribute actually `unsafe`)
 - #160198 (Rework `smallest_range_containing` to handle duplicates)
 - #160362 (Split `SpannedTypeVisitor` into its own crate, `rustc_ty_walk`)
 - #160390 (autodiff: Handle slice-tailed DSTs in type trees)
 - #160420 (Suggest `cast_signed()` for overflowing signed integer literals)
 - #160516 (Add regression test for HRTB projection in closure)
 - #160520 (Add some tests for specialization)
 - #160522 (fix(bootstrap): Normalize the names of proc macro dependency crates)
 - #160523 (Add regression test for opaque type)
 - #160531 (docs: fix typo in AllowExprMetavar comment)
 - #160538 (Update expect messages in tcp.rs doc examples to follow the style guide)
 - #160548 (bootstrap: Register `coverage-map` and `coverage-run` aliases via a separate step)
JonathanBrouwer added a commit to JonathanBrouwer/rust that referenced this pull request Aug 5, 2026
@JonathanBrouwer
Rollup merge of rust-lang#160510 - LorrensP-2158466:res-unsafe-specul…
82c5ef1 
…ative-flag, r=petrochenkov

Resolver: (un)tracked borrows for `CmRefCell` made safe by unsafe speculative flag

Implements the tracked/untracked borrowing of `CmRefCell` such that we do not mutate *any* state during speculative resolution. Made safe by an unsafe field that requires any borrows to be dropped before the flag can change.

r? @petrochenkov
@JonathanBrouwer JonathanBrouwer mentioned this pull request Aug 5, 2026
Open
rust-bors Bot pushed a commit that referenced this pull request Aug 5, 2026
@bors
Auto merge of #160559 - JonathanBrouwer:rollup-grEEuN1, r=JonathanBro…
87212ce 
…uwer

Rollup of 25 pull requests

Successful merges:

 - #158147 (std: fix stack buffer overflow in Windows junction_point)
 - #160130 (Select cache values to verify by key fingerprint, not value fingerprint)
 - #160343 (Rename `OutlivesPredicate` to `OutlivesClause`)
 - #160360 (Remove rustc_middle dependency on rustc_hir_pretty)
 - #160387 (rustc_codegen_ssa: Correctly apply the static `--jobs-backend` limit to backend parallelism)
 - #160422 (move mir-opt miri tests to CI logic)
 - #160444 (Avoid resolving path keywords outside `TypeNS`)
 - #160510 (Resolver: (un)tracked borrows for `CmRefCell` made safe by unsafe speculative flag)
 - #155424 ([blocked] Link to proposed LLM policy in CONTRIBUTING and pull request template)
 - #158726 (std: move futex implementations into sys::sync::futex)
 - #158762 (Emit thumb code on VEX V5)
 - #159225 (Split IncrCompSession out of Session)
 - #159820 (Make the `rustc_unsafe_specialization_marker` attribute actually `unsafe`)
 - #160198 (Rework `smallest_range_containing` to handle duplicates)
 - #160362 (Split `SpannedTypeVisitor` into its own crate, `rustc_ty_walk`)
 - #160390 (autodiff: Handle slice-tailed DSTs in type trees)
 - #160420 (Suggest `cast_signed()` for overflowing signed integer literals)
 - #160501 (Add bootstrap CLI snapshot test for testing miri)
 - #160516 (Add regression test for HRTB projection in closure)
 - #160520 (Add some tests for specialization)
 - #160522 (fix(bootstrap): Normalize the names of proc macro dependency crates)
 - #160523 (Add regression test for opaque type)
 - #160531 (docs: fix typo in AllowExprMetavar comment)
 - #160538 (Update expect messages in tcp.rs doc examples to follow the style guide)
 - #160548 (bootstrap: Register `coverage-map` and `coverage-run` aliases via a separate step)
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