refactor fudge_inference, handle effect vars

[lcnr]

this makes it easier to use fudging outside of fudge_inference_if_ok, which is likely necessary to handle inference variable leaks on rollback.

We now also uses exhaustive matches where possible and improve the code to handle effect vars.

r? @compiler-errors @BoxyUwU

[lcnr]

@bors try @rust-timer queue

[bors]

⌛ Trying commit d836d35 with merge 18ddfc8...

[bors]

☀️ Try build successful - checks-actions
Build commit: 18ddfc8 (18ddfc874947143563dc44c8718a75eb956f0c7d)

[rust-timer]

Finished benchmarking commit (18ddfc8): comparison URL.

Overall result: ❌ regressions - no action needed

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

@bors rollup=never
@rustbot label: -S-waiting-on-perf -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%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (secondary -2.7%)

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)	-	-	0
Improvements ✅ (secondary)	-2.7%	[-2.7%, -2.7%]	1
All ❌✅ (primary)	-	-	0

Cycles

Results (secondary -6.5%)

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)	-	-	0
Improvements ✅ (secondary)	-6.5%	[-8.9%, -3.2%]	12
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 781.3s -> 782.228s (0.12%)
Artifact size: 333.79 MiB -> 333.80 MiB (0.00%)

[compiler-errors]

@bors r+

[bors]

📌 Commit d836d35 has been approved by compiler-errors

It is now in the queue for this repository.

[bors]

⌛ Testing commit d836d35 with merge 54791ef...

[bors]

☀️ Test successful - checks-actions
Approved by: compiler-errors
Pushing 54791ef to master...

[rust-timer]

Finished benchmarking commit (54791ef): 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
Regressions ❌ (secondary)	0.2%	[0.2%, 0.2%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary 0.1%)

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)	1.8%	[1.8%, 1.8%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-1.6%	[-1.6%, -1.6%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.1%	[-1.6%, 1.8%]	2

Cycles

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

Binary size

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

Bootstrap: 781.579s -> 782.091s (0.07%)
Artifact size: 333.76 MiB -> 333.78 MiB (0.00%)