Add filter with following segment while lookup typo for path

[chenyukang]

From the discussion: #112917 (comment)

Seems we can not get the assoc items for Struct, Enum in the resolving phase.
A obvious filter is avoid suggesting the same name with the following segment path.

Use following_seg can extend the function smart_resolve_partial_mod_path_errors for more scenarios, such as std::sync_error::atomic::AtomicBool in test case.

r? @estebank

[estebank]

I'm noticing that these suggestions are now redundant. Could we check if the first suggestion has been emitted, and if so not try the import one?

[chenyukang]

It's a little bit redundant, but sometimes the import one is the right advice to fix an error, I changed the code to skip the import suggestions if typo is found, and found this case changed:

error[E0433]: failed to resolve: use of undeclared type `FromIterator`
  --> $DIR/suggest-tryinto-edition-change.rs:23:22
   |
LL |     let _v: Vec<_> = FromIterator::from_iter(&[1]);
   |                      ^^^^^^^^^^^^ use of undeclared type `FromIterator`
   |
   = note: 'std::iter::FromIterator' is included in the prelude starting in Edition 2021
   = note: 'core::iter::FromIterator' is included in the prelude starting in Edition 2021
help: a trait with a similar name exists
   |
LL |     let _v: Vec<_> = IntoIterator::from_iter(&[1]);
   |                      ~~~~~~~~~~~~
help: consider importing one of these items
   |
LL + use core::iter::FromIterator;
   |
LL + use std::iter::FromIterator;
   |

it's better than the new result after code changed:

error[E0433]: failed to resolve: use of undeclared type `FromIterator`
  --> $DIR/suggest-tryinto-edition-change.rs:23:22
   |
LL |     let _v: Vec<_> = FromIterator::from_iter(&[1]);
   |                      ^^^^^^^^^^^^
   |                      |
   |                      use of undeclared type `FromIterator`
   |                      help: a trait with a similar name exists: `IntoIterator`

we are unsure which is better in all scenarios, so let's keep it right now.

[estebank]

r=me, with #113331 (comment) addressed or not

[chenyukang]

@bors r=estebank

[bors]

📌 Commit 37b40e5 has been approved by estebank

It is now in the queue for this repository.