Use note for pointing at bound introducing requirement

[estebank]

Modify output for pointing where a trait bound obligation is introduced in an E0277 from using a span label to using a note in order to always preserve order of the output:

Before:

error[E0277]: `<<Self as Case1>::A as Iterator>::Item` doesn't implement `Debug`
--> $DIR/bounds-on-assoc-in-trait.rs:18:28
|
LL | type A: Iterator<Item: Debug>;
| ^^^^^ `<<Self as Case1>::A as Iterator>::Item` cannot be formatted using `{:?}` because it doesn't implement `Debug`
|
::: $SRC_DIR/core/src/fmt/mod.rs:LL:COL
|
LL | pub trait Debug {
| --------------- required by this bound in `Debug`
|
= help: the trait `Debug` is not implemented for `<<Self as Case1>::A as Iterator>::Item`

After:

error[E0277]: `<<Self as Case1>::A as Iterator>::Item` doesn't implement `Debug`
--> $DIR/bounds-on-assoc-in-trait.rs:18:28
|
LL | type A: Iterator<Item: Debug>;
| ^^^^^ `<<Self as Case1>::A as Iterator>::Item` cannot be formatted using `{:?}` because it doesn't implement `Debug`
|
= help: the trait `Debug` is not implemented for `<<Self as Case1>::A as Iterator>::Item`
note: required by a bound in `Debug`
--> $SRC_DIR/core/src/fmt/mod.rs:LL:COL
|
LL | pub trait Debug {
| ^^^^^^^^^^^^^^^ required by this bound in `Debug`

[oli-obk]

@bors r+

[bors]

📌 Commit 6ba8f4014ee54853ef1feef137b791f45434db6b has been approved by oli-obk

[bors]

⌛ Testing commit 6ba8f4014ee54853ef1feef137b791f45434db6b with merge 8fede0d5477807ad58586f7ac253262b3a2b8e4c...

[bors]

💔 Test failed - checks-actions

[estebank]

@bors r=oli-obk

[bors]

📌 Commit 86abc02437695649886c85a6e2b73d20a20989a7 has been approved by oli-obk

[bors]

🔒 Merge conflict

This pull request and the master branch diverged in a way that cannot be automatically merged. Please rebase on top of the latest master branch, and let the reviewer approve again.

How do I rebase?

Assuming self is your fork and upstream is this repository, you can resolve the conflict following these steps:

1. git checkout tweak-bound-output(switch to your branch)
2. git fetch upstream master(retrieve the latest master)
3. git rebase upstream/master -p(rebase on top of it)
4. Follow the on-screen instruction to resolve conflicts (check git status if you got lost).
5. git push self tweak-bound-output --force-with-lease(update this PR)

You may also read Git Rebasing to Resolve Conflicts by Drew Blessing for a short tutorial.

Please avoid the "Resolve conflicts" button on GitHub. It uses git merge instead of git rebase which makes the PR commit history more difficult to read.

Sometimes step 4 will complete without asking for resolution. This is usually due to difference between how Cargo.lock conflict is handled during merge and rebase. This is normal, and you should still perform step 5 to update this PR.

Error message

Auto-merging src/test/ui/generic-associated-types/projection-bound-cycle.stderr
CONFLICT (content): Merge conflict in src/test/ui/generic-associated-types/projection-bound-cycle.stderr
Auto-merging src/test/ui/generic-associated-types/projection-bound-cycle-generic.stderr
CONFLICT (content): Merge conflict in src/test/ui/generic-associated-types/projection-bound-cycle-generic.stderr
Auto-merging compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
Automatic merge failed; fix conflicts and then commit the result.

[bors]

☔ The latest upstream changes (presumably #87375) made this pull request unmergeable. Please resolve the merge conflicts.

[estebank]

@bors r=oli-obk

[bors]

📌 Commit 39f220c has been approved by oli-obk

[bors]

⌛ Testing commit 39f220c with merge aa8f27b...

[bors]

☀️ Test successful - checks-actions
Approved by: oli-obk
Pushing aa8f27b to master...