Don't use can_eq in derive(..) suggestion for missing method

[compiler-errors]

Unsatisfied predicates returned from method probe may reference inference vars from that probe, so drop this extra check I added in #110877 for more accurate derive suggestions...

Fixes #111500

[rustbot]

r? @davidtwco

(rustbot has picked a reviewer for you, use r? to override)

[apiraino]

r? compiler

[jackh726]

@bors r+ rollup

[bors]

📌 Commit c5604cd has been approved by jackh726

It is now in the queue for this repository.

[bors]

⌛ Testing commit c5604cd with merge 8177591...

[bors]

☀️ Test successful - checks-actions
Approved by: jackh726
Pushing 8177591 to master...

[rust-timer]

Finished benchmarking commit (8177591): 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)

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)	2.2%	[2.2%, 2.2%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	2.2%	[2.2%, 2.2%]	1

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)	3.3%	[1.3%, 4.3%]	7
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	3.3%	[1.3%, 4.3%]	7

Binary size

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

Bootstrap: 647.604s -> 647.289s (-0.05%)

[lqd]

PR #110877 has landed on stable a couple weeks ago, so the diagnostics ICE #111500 and similar happen there now, while beta and nightly are fine thanks to this PR.

So if there's ever a 1.71 point release, it could be interesting to backport this PR to stable :

• it's small and self-contained and the backport should be easy
• some duplicate issues have been opened since the release, e.g. rustc panics on Vec::sort_by on type without PartialOrd #114049, Compiler panic, partial_cmp #114056, Compiler panic, partial_cmp #114056 (comment)
• michael says it can't hurt to nominate for discussion

These couple duplicate issues likely wouldn't warrant such a point release by themselves, and the ICE should be rare enough in practice, but we'll see if more people encounter this in the future.

Nominating for discussion for stable backport.

@rustbot label +stable-nominated

[cuviper]

So if there's ever a 1.71 point release,

We are planning 1.71.1 for August 3rd:
https://rust-lang.zulipchat.com/#narrow/stream/241545-t-release/topic/1.2E71.2E1

[apiraino]

Stable backport approved as per compiler team on Zulip

@rustbot label +stable-accepted