Skip to content

suggest declaring modules when file found but module not defined #142730

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom
Open
wants to merge 7 commits into
base: master
Choose a base branch
from
Open

suggest declaring modules when file found but module not defined #142730

wants to merge 7 commits into from
+63 −1

Conversation

bend-n
Copy link
Contributor

@bend-n bend-n commented Jun 19, 2025 •
edited
Loading

suggests declaring modules when a module is found but not defined, i.e

├── main.rs: `use thing::thang;`
└── thing.rs: `struct thang`

or

├── main.rs: `use thing::thang;`
└── thing
    └── mod.rs: `struct thang`

which currently is just

error[E0432]: unresolved import `yeah`
 --> src/main.rs:1:1
  |
1 | use thing::thang;
  |     ^^^^^ use of unresolved module or unlinked crate `thing`
  |

but now would have this nice help:

= help: you may have forgotten to declare the module `thing`. use `mod thing` in this file to declare this module.

@rustbot rustbot added the T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. label Jun 19, 2025
@bend-n
Copy link
Contributor Author

bend-n commented Jun 19, 2025

@rustbot label A-diagnostics

@rustbot rustbot added the A-diagnostics Area: Messages for errors, warnings, and lints label Jun 19, 2025
@rust-log-analyzer

This comment has been minimized.

Sign in to view
@bend-n bend-n marked this pull request as ready for review June 20, 2025 12:00
@rustbot
Copy link
Collaborator

rustbot commented Jun 20, 2025

r? @petrochenkov

rustbot has assigned @petrochenkov.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

@rustbot rustbot added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jun 20, 2025
@rust-log-analyzer

This comment has been minimized.

Sign in to view
@bend-n bend-n force-pushed the suggest_declaring_modules_when_file_found_but_module_not_defined branch from 7174cb4 to 397c51b Compare June 20, 2025 13:41
petrochenkov
petrochenkov reviewed Jun 23, 2025
View reviewed changes
compiler/rustc_resolve/src/diagnostics.rs Outdated
.iter()
.flatten(),
)
.find(|x| x.exists())
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Could you avoid placing complex multi-line logic into if conditions?
This whole iter-find part would probably look better as imperative for loops anyway.

compiler/rustc_resolve/src/diagnostics.rs Outdated
&& let i = ident.as_str()
// FIXME: add case where non parent using undeclared module (hard?)
&& let Some(dir) = src.parent()
&& let Some(src) = src.with_extension("").file_name().and_then(|x| x.to_str())
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Suggested change
&& let Some(src) = src.with_extension("").file_name().and_then(|x| x.to_str())
&& let Some(src) = src.file_stem().and_then(|x| x.to_str())

?

compiler/rustc_resolve/src/diagnostics.rs Outdated
m.display()
),
Applicability::MaybeIncorrect,
))
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Could you move this new logic to a separate function?

compiler/rustc_resolve/src/diagnostics.rs Outdated
)
.shrink_to_lo();
Some((
vec![(sp, format!("mod {ident}\n"))],
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Suggested change
vec![(sp, format!("mod {ident}\n"))],
vec![(sp, format!("mod {ident};\n"))],

compiler/rustc_resolve/src/diagnostics.rs Outdated
{
let sp = map
.span_extend_to_prev_char(
map.span_extend_to_prev_char(ident.span, '\n', true),
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This looks like something UsePlacementFinder should typically do.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

thats for the position of a use though, if im reading it right? not a mod?

Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

They are typically placed next to each other, so it should work.

@petrochenkov petrochenkov added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jun 23, 2025
@bend-n bend-n force-pushed the suggest_declaring_modules_when_file_found_but_module_not_defined branch from c1a4a41 to 18ca511 Compare June 23, 2025 17:13
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Reviewers

@petrochenkov petrochenkov petrochenkov left review comments

Assignees

@petrochenkov petrochenkov

Labels
A-diagnostics Area: Messages for errors, warnings, and lints S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.
Projects
None yet
Milestone
No milestone
Development

Successfully merging this pull request may close these issues.
4 participants
@bend-n @rust-log-analyzer @rustbot @petrochenkov