Structured use suggestion on privacy error

[estebank]

When encoutering a privacy error on an item through a re-export that is accessible in an alternative path, provide a structured suggestion with that path.

error[E0603]: module import `mem` is private
  --> $DIR/private-std-reexport-suggest-public.rs:4:14
   |
LL |     use foo::mem;
   |              ^^^ private module import
   |
note: the module import `mem` is defined here...
  --> $DIR/private-std-reexport-suggest-public.rs:8:9
   |
LL |     use std::mem;
   |         ^^^^^^^^
note: ...and refers to the module `mem` which is defined here
  --> $SRC_DIR/std/src/lib.rs:LL:COL
   |
   = note: you could import this
help: import `mem` through the re-export
   |
LL |     use std::mem;
   |         ~~~~~~~~

Fix #42909.

[rustbot]

r? @b-naber

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[b-naber]

r=me with or without addressing the nit.

[b-naber]

report_privacy_error is more than 200 lines long after this change ^^ and i find it really difficult to read because all the path collection logic is all over the place. I think it would be better if we would re-structure some of the logic into functions. But it's not too important to me since this is only diagnostics code, so up to you whether you want to change this or not.

[estebank]

Let's split this method in a follow up PR.

[estebank]

@bors r=b-naber

[bors]

📌 Commit beaf315 has been approved by b-naber

It is now in the queue for this repository.

[bors]

⌛ Testing commit beaf315 with merge 9358642...

[bors]

☀️ Test successful - checks-actions
Approved by: b-naber
Pushing 9358642 to master...

[rust-timer]

Finished benchmarking commit (9358642): comparison URL.

Overall result: ❌ regressions - no action needed

@rustbot label: -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)	0.2%	[0.2%, 0.3%]	3
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

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)	1.1%	[1.1%, 1.1%]	1
Regressions ❌ (secondary)	1.3%	[1.3%, 1.3%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.4%	[-3.9%, -2.9%]	2
All ❌✅ (primary)	1.1%	[1.1%, 1.1%]	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)	-	-	0
Regressions ❌ (secondary)	2.7%	[2.2%, 3.2%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 673.262s -> 675.321s (0.31%)
Artifact size: 314.18 MiB -> 314.15 MiB (-0.01%)