[perf] Compute hard errors without diagnostics in impl_intersection_has_impossible_obligation

[compiler-errors]

First compute hard errors without diagnostics, then ambiguities with diagnostics since we need to know if any of them overflowed.

[compiler-errors]

@bors2 try @rust-timer queue

[rust-bors]

⌛ Trying commit 15a8f83 with merge f6e2337…

To cancel the try build, run the command @bors2 try cancel.

[rust-bors]

☀️ Try build successful (CI)
Build commit: f6e2337 (f6e233705a1a56780a1d4f57fb6b14373f60468c, parent: f3db63916e541ff039ac3cd7364c2d612749b61b)

[rust-timer]

Finished benchmarking commit (f6e2337): comparison URL.

Overall result: ✅ improvements - no action needed

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

@bors rollup=never
@rustbot label: -S-waiting-on-perf -perf-regression

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

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

Max RSS (memory usage)

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

Cycles

Results (secondary -4.0%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-4.0%	[-4.0%, -4.0%]	1
All ❌✅ (primary)	-	-	0

Binary size

Results (secondary 0.0%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

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

Bootstrap: 692.654s -> 692.684s (0.00%)
Artifact size: 372.15 MiB -> 372.15 MiB (-0.00%)

[compiler-errors]

I think it's still worth landing 👍 could be worse in pathological cases.

[rustbot]

This PR changes a file inside tests/crashes. If a crash was fixed, please move into the corresponding ui subdir and add 'Fixes #' to the PR description to autoclose the issue upon merge.

[compiler-errors]

Coincidentally fixes this error. I'll put up a correct fix.