Encode implied predicates for traits

[compiler-errors]

In #112629, we decided to make associated type bounds in the "supertrait" AST position implied even though they're not supertraits themselves.

This means that the super_predicates and implied_predicates queries now differ for regular traits. The assumption that they didn't differ was hard-coded in #107614, so in cross-crate positions this means that we forget the implied predicates from associated type bounds.

This isn't unsound, just kind of annoying. This should be backported since associated type bounds are slated to stabilize for 1.78 -- either that, or associated type bounds can be reverted on beta and re-shipped in 1.79 with this patch.

Fixes #122859

[rustbot]

r? @Nadrieril

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[compiler-errors]

r? @oli-obk

[compiler-errors]

@bors try @rust-timer queue

if this ends up being a lot of work, I can make it so that we only encode implied predicates if they differ from super predicates.

[bors]

⌛ Trying commit 3361488 with merge b350b0b...

[bors]

☀️ Try build successful - checks-actions
Build commit: b350b0b (b350b0bacc17017632f1c6ffe90c01021245b1b8)

[rust-timer]

Finished benchmarking commit (b350b0b): 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 a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	1.5%	[1.5%, 1.5%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

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

Cycles

Results

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)	-6.8%	[-6.8%, -6.8%]	1
All ❌✅ (primary)	-	-	0

Binary size

Results

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%, 0.5%]	97
Regressions ❌ (secondary)	0.0%	[0.0%, 0.0%]	9
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.1%	[0.0%, 0.5%]	97

Bootstrap: 669.525s -> 671.037s (0.23%)
Artifact size: 314.91 MiB -> 315.07 MiB (0.05%)

[slanterns]

associated type bounds are slated to stabilize for 1.78

I think the merge of ATB happens after the beta-cutoff, and it does not get into 1.78 beta?

[oli-obk]

@bors r+

[bors]

📌 Commit 3361488 has been approved by oli-obk

It is now in the queue for this repository.

[bors]

⌛ Testing commit 3361488 with merge 6a92312...

[bors]

☀️ Test successful - checks-actions
Approved by: oli-obk
Pushing 6a92312 to master...

[rust-timer]

Finished benchmarking commit (6a92312): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

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

Max RSS (memory usage)

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

Cycles

Results

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)	0.8%	[0.8%, 0.8%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.8%	[0.8%, 0.8%]	1

Binary size

Results

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%, 0.5%]	97
Regressions ❌ (secondary)	0.0%	[0.0%, 0.0%]	8
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.1%	[0.0%, 0.5%]	97

Bootstrap: 669.922s -> 670.64s (0.11%)
Artifact size: 315.00 MiB -> 315.10 MiB (0.03%)

[apiraino]

Beta backport accepted as per compiler team on Zulip. A backport PR will be authored by the release team at the end of the current development cycle.

@rustbot label +beta-accepted

[cuviper]

This should be backported since associated type bounds are slated to stabilize for 1.78

The backported test fails, error[E0658]: associated type bounds are unstable -- I think it's only in 1.79 per #122055. Should we cancel this backport? or just add #![feature(associated_type_bounds)] to the backported test?

[cuviper]

Removing the backport after the followup on zulip.

@rustbot label -beta-nominated -beta-accepted