StateTransform: Do not renumber resume local.#146552

cjgillot · 2025-09-14T19:32:45Z

MIR parameters are not explicitly assigned-to when entering the MIR body. If we want to save their values inside the coroutine state, we need to do so explicitly.

This was done by renaming the _2 local, and introducing an explicit assignment pre-transform. This particular trick confuses me.

This version makes explicit that we are assigning parameters to saved locals.

r? @dingxiangfei2009

rustbot · 2025-09-14T19:32:49Z

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

rustbot · 2025-09-14T19:32:50Z

Failed to set assignee to dingxiangfei2009: invalid assignee

Note: Only org members with at least the repository "read" role, users with write permissions, or people who have commented on the PR may be assigned.

cjgillot · 2025-09-14T23:50:57Z

r? compiler

jackh726 · 2025-09-16T07:06:28Z

Seems reasonable to me. Curious if there was some particular reason this was written this way.

@bors r+

bors · 2025-09-16T07:06:31Z

📌 Commit c1bda59 has been approved by jackh726

It is now in the queue for this repository.

StateTransform: Do not renumber resume local. MIR parameters are not explicitly assigned-to when entering the MIR body. If we want to save their values inside the coroutine state, we need to do so explicitly. This was done by renaming the `_2` local, and introducing an explicit assignment pre-transform. This particular trick confuses me. This version makes explicit that we are assigning parameters to saved locals. r? `@dingxiangfei2009`

Rollup of 4 pull requests Successful merges: - #143613 (Fix backtraces with `-C panic=abort` on linux; emit unwind tables by default) - #145181 (remove FIXME block from `has_significant_drop`, it never encounters inference variables) - #146552 (StateTransform: Do not renumber resume local.) - #146588 (tests/run-make: Update list of statically linked musl targets) r? `@ghost` `@rustbot` modify labels: rollup

Zalathar · 2025-09-16T08:23:43Z

Probably failed in rollup: #146625 (comment)

@bors r-

rustbot · 2025-09-16T22:59:19Z

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

cjgillot · 2025-09-16T23:50:46Z

@bors r=jackh726

bors · 2025-09-16T23:50:49Z

📌 Commit eddd755 has been approved by jackh726

It is now in the queue for this repository.

StateTransform: Do not renumber resume local. MIR parameters are not explicitly assigned-to when entering the MIR body. If we want to save their values inside the coroutine state, we need to do so explicitly. This was done by renaming the `_2` local, and introducing an explicit assignment pre-transform. This particular trick confuses me. This version makes explicit that we are assigning parameters to saved locals. r? `@dingxiangfei2009`

Rollup of 14 pull requests Successful merges: - #142807 (libtest: expose --fail-fast as an unstable command-line option) - #144871 (Stabilize `btree_entry_insert` feature) - #145071 (Update the minimum external LLVM to 20) - #145181 (remove FIXME block from `has_significant_drop`, it never encounters inference variables) - #145660 (initial implementation of the darwin_objc unstable feature) - #145838 (don't apply temporary lifetime extension rules to non-extended `super let`) - #146259 (Suggest removing Box::new instead of unboxing it) - #146410 (Iterator repeat: no infinite loop for `last` and `count`) - #146460 (Add tidy readme) - #146552 (StateTransform: Do not renumber resume local.) - #146564 (Remove Rvalue::Len again.) - #146581 (Detect attempt to use var-args in closure) - #146588 (tests/run-make: Update list of statically linked musl targets) - #146631 (cg_llvm: Replace some DIBuilder wrappers with LLVM-C API bindings (part 3)) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of #146552 - cjgillot:resume-noremap, r=jackh726 StateTransform: Do not renumber resume local. MIR parameters are not explicitly assigned-to when entering the MIR body. If we want to save their values inside the coroutine state, we need to do so explicitly. This was done by renaming the `_2` local, and introducing an explicit assignment pre-transform. This particular trick confuses me. This version makes explicit that we are assigning parameters to saved locals. r? ``@dingxiangfei2009``

Rollup of 14 pull requests Successful merges: - rust-lang/rust#142807 (libtest: expose --fail-fast as an unstable command-line option) - rust-lang/rust#144871 (Stabilize `btree_entry_insert` feature) - rust-lang/rust#145071 (Update the minimum external LLVM to 20) - rust-lang/rust#145181 (remove FIXME block from `has_significant_drop`, it never encounters inference variables) - rust-lang/rust#145660 (initial implementation of the darwin_objc unstable feature) - rust-lang/rust#145838 (don't apply temporary lifetime extension rules to non-extended `super let`) - rust-lang/rust#146259 (Suggest removing Box::new instead of unboxing it) - rust-lang/rust#146410 (Iterator repeat: no infinite loop for `last` and `count`) - rust-lang/rust#146460 (Add tidy readme) - rust-lang/rust#146552 (StateTransform: Do not renumber resume local.) - rust-lang/rust#146564 (Remove Rvalue::Len again.) - rust-lang/rust#146581 (Detect attempt to use var-args in closure) - rust-lang/rust#146588 (tests/run-make: Update list of statically linked musl targets) - rust-lang/rust#146631 (cg_llvm: Replace some DIBuilder wrappers with LLVM-C API bindings (part 3)) r? `@ghost` `@rustbot` modify labels: rollup

Rollup of 14 pull requests Successful merges: - rust-lang#142807 (libtest: expose --fail-fast as an unstable command-line option) - rust-lang#144871 (Stabilize `btree_entry_insert` feature) - rust-lang#145071 (Update the minimum external LLVM to 20) - rust-lang#145181 (remove FIXME block from `has_significant_drop`, it never encounters inference variables) - rust-lang#145660 (initial implementation of the darwin_objc unstable feature) - rust-lang#145838 (don't apply temporary lifetime extension rules to non-extended `super let`) - rust-lang#146259 (Suggest removing Box::new instead of unboxing it) - rust-lang#146410 (Iterator repeat: no infinite loop for `last` and `count`) - rust-lang#146460 (Add tidy readme) - rust-lang#146552 (StateTransform: Do not renumber resume local.) - rust-lang#146564 (Remove Rvalue::Len again.) - rust-lang#146581 (Detect attempt to use var-args in closure) - rust-lang#146588 (tests/run-make: Update list of statically linked musl targets) - rust-lang#146631 (cg_llvm: Replace some DIBuilder wrappers with LLVM-C API bindings (part 3)) r? `@ghost` `@rustbot` modify labels: rollup

Rollup of 14 pull requests Successful merges: - rust-lang/rust#142807 (libtest: expose --fail-fast as an unstable command-line option) - rust-lang/rust#144871 (Stabilize `btree_entry_insert` feature) - rust-lang/rust#145071 (Update the minimum external LLVM to 20) - rust-lang/rust#145181 (remove FIXME block from `has_significant_drop`, it never encounters inference variables) - rust-lang/rust#145660 (initial implementation of the darwin_objc unstable feature) - rust-lang/rust#145838 (don't apply temporary lifetime extension rules to non-extended `super let`) - rust-lang/rust#146259 (Suggest removing Box::new instead of unboxing it) - rust-lang/rust#146410 (Iterator repeat: no infinite loop for `last` and `count`) - rust-lang/rust#146460 (Add tidy readme) - rust-lang/rust#146552 (StateTransform: Do not renumber resume local.) - rust-lang/rust#146564 (Remove Rvalue::Len again.) - rust-lang/rust#146581 (Detect attempt to use var-args in closure) - rust-lang/rust#146588 (tests/run-make: Update list of statically linked musl targets) - rust-lang/rust#146631 (cg_llvm: Replace some DIBuilder wrappers with LLVM-C API bindings (part 3)) r? `@ghost` `@rustbot` modify labels: rollup

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 Sep 14, 2025

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cjgillot force-pushed the resume-noremap branch from fb00c01 to 2dc12f6 Compare September 14, 2025 20:52

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cjgillot force-pushed the resume-noremap branch from 2dc12f6 to c1bda59 Compare September 14, 2025 21:49

rustbot assigned jackh726 Sep 14, 2025

bors 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 Sep 16, 2025

Zalathar mentioned this pull request Sep 16, 2025

Rollup of 4 pull requests #146625

Closed

bors 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-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Sep 16, 2025

cjgillot added 3 commits September 16, 2025 22:50

Add test.

40d879a

Do not renumber resume local.

fe3a784

Bless ui.

eddd755

cjgillot force-pushed the resume-noremap branch from c1bda59 to eddd755 Compare September 16, 2025 22:59

bors 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-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Sep 16, 2025

This was referenced Sep 17, 2025

Rollup of 15 pull requests #146665

Closed

Rollup of 14 pull requests #146666

Merged

bors merged commit 577f18f into rust-lang:master Sep 17, 2025
10 checks passed

rustbot added this to the 1.92.0 milestone Sep 17, 2025

cjgillot deleted the resume-noremap branch September 17, 2025 10:51

github-actions bot mentioned this pull request Sep 18, 2025

Toolchain upgrade to nightly-2025-10-09 flux-rs/flux#1271

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StateTransform: Do not renumber resume local.#146552