Unschedule moved locals

[cjgillot]

Alternative to #159537

This extracts part of the implementation from #125923.

Instead of maintaining a bit-set of locals that are moved from the innermost scope, this PR just removes the locals from the drop schedule.

r? @ghost for perf, and because of a borrowck corner case

[cjgillot]

@bors try @rust-timer queue

[rust-log-analyzer]

The job aarch64-gnu-llvm-21-1 failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

---- [ui] tests/ui/mir/issue-80949.rs stdout ----

error: test compilation failed although it shouldn't!
status: exit status: 1
command: env -u RUSTC_LOG_COLOR RUSTC_ICE="0" RUST_BACKTRACE="short" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/tests/ui/mir/issue-80949.rs" "-Zthreads=1" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=/cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=/checkout/vendor" "--sysroot" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2" "--target=aarch64-unknown-linux-gnu" "--check-cfg" "cfg(test,FALSE)" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/aarch64-unknown-linux-gnu/test/ui/mir/issue-80949" "-A" "unused" "-W" "unused_attributes" "-A" "internal_features" "-A" "incomplete_features" "-A" "unused_parens" "-A" "unused_braces" "-Crpath" "-Cdebuginfo=0" "-Lnative=/checkout/obj/build/aarch64-unknown-linux-gnu/native/rust-test-helpers"
stdout: none
--- stderr -------------------------------
error[E0597]: `storage` does not live long enough
##[error]  --> /checkout/tests/ui/mir/issue-80949.rs:32:23
   |
---
LL |     diff(dyn_trait, storage_ref);
LL | }
   | -
   | |
   | `storage` dropped here while still borrowed
   | borrow might be used here, when `dyn_trait` is dropped and runs the destructor for type `Box<dyn Trait<Item = &()>>`
   |
   = note: values in a scope are dropped in the opposite order they are defined

error: aborting due to 1 previous error

[rust-bors]

☀️ Try build successful (CI)
Build commit: ab0430c (ab0430cfc09675383a04ad2a1b7877ec314aaac9)
Base parent: 9f36de7 (9f36de775bc636c8e88c31a173c2bcb6995956a0)

[rust-timer]

Finished benchmarking commit (ab0430c): comparison URL.

Overall result: ❌✅ regressions and improvements - please read:

Benchmarking means the PR may be perf-sensitive. It's automatically marked not fit for rolling up. Overriding is possible but disadvised: it risks changing compiler perf.

Next, please: If you can, justify the regressions found in this try perf run in writing along with @rustbot label: +perf-regression-triaged. If not, fix the regressions and do another perf run. Neutral or positive results will clear the label automatically.

@bors rollup=never rustc-perf
@rustbot label: -S-waiting-on-perf +perf-regression

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	0.5%	[0.4%, 0.5%]	6
Regressions ❌ (secondary)	0.3%	[0.2%, 0.3%]	2
Improvements ✅ (primary)	-0.5%	[-1.0%, -0.2%]	53
Improvements ✅ (secondary)	-0.4%	[-1.0%, -0.2%]	44
All ❌✅ (primary)	-0.4%	[-1.0%, 0.5%]	59

Max RSS (memory usage)

Results (primary -0.7%, secondary -0.7%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.7%	[-0.9%, -0.5%]	3
Improvements ✅ (secondary)	-0.7%	[-0.7%, -0.7%]	1
All ❌✅ (primary)	-0.7%	[-0.9%, -0.5%]	3

Cycles

Results (primary -2.3%, secondary -1.4%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-2.3%	[-2.4%, -2.3%]	2
Improvements ✅ (secondary)	-1.4%	[-1.4%, -1.4%]	1
All ❌✅ (primary)	-2.3%	[-2.4%, -2.3%]	2

Binary size

Results (primary -0.4%, secondary -0.2%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	0.6%	[0.6%, 0.6%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.4%	[-1.9%, -0.0%]	42
Improvements ✅ (secondary)	-0.2%	[-1.9%, -0.0%]	30
All ❌✅ (primary)	-0.4%	[-1.9%, 0.6%]	43

Bootstrap: 484.26s -> 485.704s (0.30%)
Artifact size: 391.74 MiB -> 391.76 MiB (0.01%)