Revert #127731 "Emit error when calling/declaring functions with unavailable …"

[lqd]

This reverts #127731 due to the unexpected perf regressions and to give time to mitigate the regressions before re-landing it.

r? @RalfJung cc @veluca93

[compiler-errors]

wow what a regression 😨

@bors r+ rollup=never

[bors]

📌 Commit bd8477b has been approved by compiler-errors

It is now in the queue for this repository.

[bors]

⌛ Testing commit bd8477b with merge ae4c6b6...

[bors]

☀️ Test successful - checks-actions
Approved by: compiler-errors
Pushing ae4c6b6 to master...

[rust-timer]

Finished benchmarking commit (ae4c6b6): comparison URL.

Overall result: ✅ improvements - 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
Regressions ❌ (secondary)	0.3%	[0.3%, 0.3%]	1
Improvements ✅ (primary)	-4.7%	[-14.4%, -0.3%]	75
Improvements ✅ (secondary)	-4.5%	[-22.7%, -0.2%]	27
All ❌✅ (primary)	-4.7%	[-14.4%, -0.3%]	75

Max RSS (memory usage)

Results (primary -4.1%, secondary -2.6%)

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)	3.0%	[2.8%, 3.3%]	2
Improvements ✅ (primary)	-4.1%	[-10.3%, -1.0%]	65
Improvements ✅ (secondary)	-3.1%	[-5.3%, -0.9%]	22
All ❌✅ (primary)	-4.1%	[-10.3%, -1.0%]	65

Cycles

Results (primary -9.6%, secondary -8.8%)

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)	2.6%	[2.3%, 2.8%]	2
Regressions ❌ (secondary)	4.0%	[3.4%, 5.2%]	3
Improvements ✅ (primary)	-10.0%	[-20.6%, -1.6%]	53
Improvements ✅ (secondary)	-12.6%	[-27.7%, -0.9%]	10
All ❌✅ (primary)	-9.6%	[-20.6%, 2.8%]	55

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 787.606s -> 785.03s (-0.33%)
Artifact size: 333.58 MiB -> 333.74 MiB (0.05%)