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Emit a single error when importing a path with _ #142805

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a56bf51
Make some `use _` tests multi-edition
estebank Jun 20, 2025
b52efaa
Emit a single error when importing a path with `_`
estebank Jun 20, 2025
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6 changes: 6 additions & 0 deletions compiler/rustc_resolve/src/imports.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -711,6 +711,12 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {

let mut diag = struct_span_code_err!(self.dcx(), span, E0432, "{msg}");

if errors.iter().all(|(_, err)| err.segment == Some(kw::Underscore)) {
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This leads to inconsistent behavior in code like use {_, a}. I'd rather we filter out the errors mentioning _ like we're doing with that errors.retain call above.

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And while we're at it, we probably should delay a bug in the:

if errors.is_empty() {
    return;
}

on 691.

// If we've encountered something like `use _;`, we've already emitted an error stating
// that `_` is not a valid identifier, so we silence the resolve error.
diag.downgrade_to_delayed_bug();
}

if let Some((_, UnresolvedImportError { note: Some(note), .. })) = errors.iter().last() {
diag.note(note.clone());
}
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2 changes: 1 addition & 1 deletion ...ple-extern-by-macro-for-underscore.stderr → ...ern-by-macro-for-underscore.ed2015.stderr
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
error: expected identifier, found reserved identifier `_`
--> $DIR/multiple-extern-by-macro-for-underscore.rs:16:11
--> $DIR/multiple-extern-by-macro-for-underscore.rs:18:11
|
LL | use ::_;
| ^ expected identifier, found reserved identifier
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8 changes: 8 additions & 0 deletions tests/ui/imports/multiple-extern-by-macro-for-underscore.ed2021.stderr
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Original file line number Diff line number Diff line change
@@ -0,0 +1,8 @@
error: expected identifier, found reserved identifier `_`
--> $DIR/multiple-extern-by-macro-for-underscore.rs:18:11
|
LL | use ::_;
| ^ expected identifier, found reserved identifier

error: aborting due to 1 previous error

4 changes: 3 additions & 1 deletion tests/ui/imports/multiple-extern-by-macro-for-underscore.rs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,6 @@
//@ edition: 2021
//@ revisions: ed2015 ed2021
//@[ed2015] edition: 2015
//@[ed2021] edition: 2021

// issue#128813

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36 changes: 6 additions & 30 deletions ...ui/underscore-imports/issue-110164.stderr → ...rscore-imports/issue-110164.ed2015.stderr
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Original file line number Diff line number Diff line change
@@ -1,17 +1,17 @@
error: expected identifier, found reserved identifier `_`
--> $DIR/issue-110164.rs:5:5
--> $DIR/issue-110164.rs:8:5
|
LL | use _::a;
| ^ expected identifier, found reserved identifier

error: expected identifier, found reserved identifier `_`
--> $DIR/issue-110164.rs:8:5
--> $DIR/issue-110164.rs:10:5
|
LL | use _::*;
| ^ expected identifier, found reserved identifier

error: expected identifier, found reserved identifier `_`
--> $DIR/issue-110164.rs:13:9
--> $DIR/issue-110164.rs:14:9
|
LL | use _::a;
| ^ expected identifier, found reserved identifier
Expand All @@ -23,41 +23,17 @@ LL | use _::*;
| ^ expected identifier, found reserved identifier

error[E0432]: unresolved import `self::*`
--> $DIR/issue-110164.rs:1:5
--> $DIR/issue-110164.rs:4:5
|
LL | use self::*;
| ^^^^^^^ cannot glob-import a module into itself

error[E0432]: unresolved import `crate::*`
--> $DIR/issue-110164.rs:3:5
--> $DIR/issue-110164.rs:6:5
|
LL | use crate::*;
| ^^^^^^^^ cannot glob-import a module into itself

error[E0432]: unresolved import `_`
--> $DIR/issue-110164.rs:8:5
|
LL | use _::*;
| ^ `_` is not a valid crate or module name

error[E0432]: unresolved import `_`
--> $DIR/issue-110164.rs:5:5
|
LL | use _::a;
| ^ `_` is not a valid crate or module name

error[E0432]: unresolved import `_`
--> $DIR/issue-110164.rs:13:9
|
LL | use _::a;
| ^ `_` is not a valid crate or module name

error[E0432]: unresolved import `_`
--> $DIR/issue-110164.rs:16:9
|
LL | use _::*;
| ^ `_` is not a valid crate or module name

error: aborting due to 10 previous errors
error: aborting due to 6 previous errors

For more information about this error, try `rustc --explain E0432`.
39 changes: 39 additions & 0 deletions tests/ui/underscore-imports/issue-110164.ed2021.stderr
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Original file line number Diff line number Diff line change
@@ -0,0 +1,39 @@
error: expected identifier, found reserved identifier `_`
--> $DIR/issue-110164.rs:8:5
|
LL | use _::a;
| ^ expected identifier, found reserved identifier

error: expected identifier, found reserved identifier `_`
--> $DIR/issue-110164.rs:10:5
|
LL | use _::*;
| ^ expected identifier, found reserved identifier

error: expected identifier, found reserved identifier `_`
--> $DIR/issue-110164.rs:14:9
|
LL | use _::a;
| ^ expected identifier, found reserved identifier

error: expected identifier, found reserved identifier `_`
--> $DIR/issue-110164.rs:16:9
|
LL | use _::*;
| ^ expected identifier, found reserved identifier

error[E0432]: unresolved import `self::*`
--> $DIR/issue-110164.rs:4:5
|
LL | use self::*;
| ^^^^^^^ cannot glob-import a module into itself

error[E0432]: unresolved import `crate::*`
--> $DIR/issue-110164.rs:6:5
|
LL | use crate::*;
| ^^^^^^^^ cannot glob-import a module into itself

error: aborting due to 6 previous errors

For more information about this error, try `rustc --explain E0432`.
7 changes: 3 additions & 4 deletions tests/ui/underscore-imports/issue-110164.rs
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Since this pr touches this test, could we also rename it with some more descriptive name and put a small comment with a link on an issue related to this instead?

Original file line number Diff line number Diff line change
@@ -1,19 +1,18 @@
//@ revisions: ed2015 ed2021
//@[ed2015] edition: 2015
//@[ed2021] edition: 2021
use self::*;
//~^ ERROR unresolved import `self::*`
use crate::*;
//~^ ERROR unresolved import `crate::*`
use _::a;
//~^ ERROR expected identifier, found reserved identifier `_`
//~| ERROR unresolved import `_`
use _::*;
//~^ ERROR expected identifier, found reserved identifier `_`
//~| ERROR unresolved import `_`

fn main() {
use _::a;
//~^ ERROR expected identifier, found reserved identifier `_`
//~| ERROR unresolved import `_`
use _::*;
//~^ ERROR expected identifier, found reserved identifier `_`
//~| ERROR unresolved import `_`
}
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