btree: don't leak value if destructor of key panics

[lukas-code]

This PR fixes a regression from #84904.

The BTreeMap already attempts to handle panicking destructors of the key-value pairs by continuing to execute the remaining destructors after one destructor panicked. However, after #84904 the destructor of a value in a key-value pair gets skipped if the destructor of the key panics, only continuing with the next key-value pair. This PR reverts to the behavior before #84904 to also drop the corresponding value if the destructor of a key panics.

This avoids potential memory leaks and can fix the soundness of programs that rely on the destructors being executed (even though this should not be relied upon, because the std collections currently do not guarantee that the remaining elements are dropped after a panic in a destructor).

cc @Amanieu because you had opinions on panicking destructors

[rustbot]

r? @jhpratt

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[jhpratt]

@bors r+

[bors]

📌 Commit e32a118 has been approved by jhpratt

It is now in the queue for this repository.

[compiler-errors]

Failed in a rollup: #133350 (comment)

@bors r-

[lukas-code]

Looks like the failure was actually #133247, so

@bors r=jhpratt

[bors]

📌 Commit e32a118 has been approved by jhpratt

It is now in the queue for this repository.

[bors]

⌛ Testing commit e32a118 with merge 124eb96...

[bors]

☀️ Test successful - checks-actions
Approved by: jhpratt
Pushing 124eb96 to master...

[rust-timer]

Finished benchmarking commit (124eb96): comparison URL.

Overall result: ❌ regressions - no action needed

@rustbot label: -perf-regression

Instruction count

This is the most reliable metric that we have; it was used to determine the overall result at the top of this comment. However, even this metric can sometimes exhibit noise.

	mean	range	count
Regressions ❌ (primary)	0.3%	[0.2%, 0.5%]	2
Regressions ❌ (secondary)	1.4%	[1.4%, 1.4%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.3%	[0.2%, 0.5%]	2

Max RSS (memory usage)

Results (primary -2.8%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	3.2%	[3.2%, 3.2%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-5.7%	[-6.8%, -4.7%]	2
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-2.8%	[-6.8%, 3.2%]	3

Cycles

Results (primary -3.3%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-3.3%	[-3.3%, -3.3%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-3.3%	[-3.3%, -3.3%]	1

Binary size

Results (primary 0.0%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.1%	[0.0%, 0.2%]	21
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.0%	[-0.0%, -0.0%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.0%	[-0.0%, 0.2%]	22

Bootstrap: 797.356s -> 796.612s (-0.09%)
Artifact size: 336.34 MiB -> 336.26 MiB (-0.03%)