Improve E0603 suggestions for private grouped imports

compiler/rustc_resolve/src/diagnostics/impls.rs

@@ -2554,11 +2554,13 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             decl,
             outermost_res,
             parent_scope,
-            single_nested,
+            root_span,
             dedup_span,
             ref source,
         } = *privacy_error;
 
+        let single_nested = dedup_span != root_span;
+
         let res = decl.res();
         let ctor_fields_span = self.ctor_fields_span(decl);
         let plain_descr = res.descr().to_string();
@@ -2811,12 +2813,11 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         // 2) the use isn't nested, otherwise `dedup_span` is one ident in `{...}`.
         //
         // See issue #156060.
-        let can_replace_use = !shown_candidates
-            && !single_nested
-            && !outermost_res.is_some_and(|(_, outer)| outer.span != ident.span);
-        if can_replace_use {
-            // We prioritize shorter paths, non-core imports and direct imports over the
-            // alternatives.
+        let can_suggest =
+            !shown_candidates && !outermost_res.is_some_and(|(_, outer)| outer.span != ident.span);
+
+        if can_suggest {
+            // We prioritize shorter paths, non-core imports and direct imports over the alternatives.
             sugg_paths.sort_by_key(|(p, reexport)| (p.len(), p[0].name == sym::core, *reexport));
             for (sugg, reexport) in sugg_paths {
                 if sugg.len() <= 1 {
@@ -2825,12 +2826,86 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                     continue;
                 }
                 let path = join_path_idents(sugg);
-                let sugg = if reexport {
-                    diagnostics::ImportIdent::ThroughReExport { span: dedup_span, ident, path }
+
+                if !single_nested {
+                    let sugg = if reexport {
+                        diagnostics::ImportIdent::ThroughReExport { span: dedup_span, ident, path }
+                    } else {
+                        diagnostics::ImportIdent::Directly { span: dedup_span, ident, path }
+                    };
+                    err.subdiagnostic(sugg);
+                    break;
+                }
+
+                // For a grouped import, suggest a standalone `use` for the correct path
+                // and remove the failing item from the existing group.
+                let (found_closing_brace, span_to_remove) =
+                    find_span_of_binding_until_next_binding(self.tcx.sess, ident.span, root_span);
+
+                let msg = if reexport {
+                    format!("import `{ident}` through the re-export")
                 } else {
-                    diagnostics::ImportIdent::Directly { span: dedup_span, ident, path }
+                    format!("import `{ident}` directly")
                 };
-                err.subdiagnostic(sugg);
+
+                let span_to_remove = if found_closing_brace {
+                    match extend_span_to_previous_binding(self.tcx.sess, span_to_remove) {
+                        Some(prev) => prev,
+                        None => {
+                            // Replace the entire statement rather than leaving an empty group.
+                            err.multipart_suggestion(
+                                msg,
+                                vec![(root_span, format!("{path}"))],
+                                Applicability::MachineApplicable,
+                            );
+                            break;
+                        }
+                    }
+                } else {
+                    span_to_remove
+                };
+
+                let indentation =
+                    self.tcx.sess.source_map().indentation_before(root_span).unwrap_or_default();
+
+                // We intentionally insert at `root_span.shrink_to_lo()` instead of a line-level
+                // span. This preserves formatting and surrounding tokens if the `use` statement
+                // is on the same line as other items (e.g. `{ use foo::{bar, baz}; }`).
+                let mut spans = vec![
+                    (root_span.shrink_to_lo(), format!("{path};\n{indentation}use ")),
+                    (span_to_remove, String::new()),
+                ];
+
+                // Strip braces if only one item remains (e.g. `foo::{Bar}` -> `foo::Bar`).
+                if let Ok(Some(extra_spans)) =
+                    self.tcx.sess.source_map().span_to_source(root_span, |src, start, end| {
+                        let src = &src[start..end];
+                        let lo = (span_to_remove.lo() - root_span.lo()).0 as usize;
+                        let hi = (span_to_remove.hi() - root_span.lo()).0 as usize;
+                        if let (Some(open), Some(close)) = (src.find('{'), src.rfind('}')) {
+                            // No other commas means exactly one item remains.
+                            if !src[open + 1..lo].contains(',') && !src[hi..close].contains(',') {
+                                let remove_char = |pos: usize| {
+                                    let lo = root_span.lo() + BytePos(pos as u32);
+                                    (
+                                        Span::new(lo, lo + BytePos(1), root_span.ctxt(), None),
+                                        String::new(),
+                                    )
+                                };
+                                return Ok::<_, rustc_span::SpanSnippetError>(Some(vec![
+                                    remove_char(open),
+                                    remove_char(close),
+                                ]));
+                            }
+                        }
+                        Ok::<_, rustc_span::SpanSnippetError>(None)
+                    })
+                {
+                    spans.extend(extra_spans);
+                }
+
+                // Insert before `root_span` to reuse the existing `use`.
+                err.multipart_suggestion(msg, spans, Applicability::MachineApplicable);
                 break;
             }
         }

compiler/rustc_resolve/src/ident.rs

@@ -1362,10 +1362,10 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                     ident,
                     decl: binding,
                     dedup_span: path_span,
+                    root_span,
                     outermost_res: None,
                     source: None,
                     parent_scope: *parent_scope,
-                    single_nested: path_span != root_span,
                 });
             } else {
                 return Err(ControlFlow::Break(Determined));

compiler/rustc_resolve/src/lib.rs

@@ -1043,11 +1043,14 @@ impl<'ra> DeclKind<'ra> {
 struct PrivacyError<'ra> {
     ident: Ident,
     decl: Decl<'ra>,
+    /// Span of the specific item being imported (e.g. `bar` in `use foo::{bar, baz}`).
+    /// Used for deduplication and single-item suggestion replacement.
     dedup_span: Span,
+    /// Span of the entire `use` path, excluding the leading `use` keyword.
+    /// Needed for grouped-import suggestions.
+    root_span: Span,
     outermost_res: Option<(Res, Ident)>,
     parent_scope: ParentScope<'ra>,
-    /// Is the format `use a::{b,c}`?
-    single_nested: bool,
     source: Option<ast::Expr>,
 }
 

tests/ui/imports/private-import-grouped-suggestion-157453.rs

@@ -0,0 +1,32 @@
+mod one {
+    pub struct One();
+}
+
+mod two {
+    use crate::one::One;
+    pub struct Two();
+}
+
+mod test_grouped {
+    use crate::two::{One, Two}; //~ ERROR struct import `One` is private [E0603]
+}
+
+mod test_single_item {
+    use crate::two::{One}; //~ ERROR struct import `One` is private [E0603]
+}
+
+mod outer {
+    pub mod inner {
+        pub struct MyPath;
+    }
+}
+
+mod reexport {
+    use crate::outer::inner::MyPath;
+}
+
+mod test_std_style {
+    use crate::reexport::{MyPath}; //~ ERROR struct import `MyPath` is private [E0603]
+}
+
+fn main() {}

tests/ui/imports/private-import-grouped-suggestion-157453.stderr

@@ -0,0 +1,69 @@
+error[E0603]: struct import `One` is private
+  --> $DIR/private-import-grouped-suggestion-157453.rs:11:22
+   |
+LL |     use crate::two::{One, Two};
+   |                      ^^^ private struct import
+   |
+note: the struct import `One` is defined here...
+  --> $DIR/private-import-grouped-suggestion-157453.rs:6:9
+   |
+LL |     use crate::one::One;
+   |         ^^^^^^^^^^^^^^^
+note: ...and refers to the struct `One` which is defined here
+  --> $DIR/private-import-grouped-suggestion-157453.rs:2:5
+   |
+LL |     pub struct One();
+   |     ^^^^^^^^^^^^^^^^^ you could import this directly
+help: import `One` directly
+   |
+LL ~     use crate::one::One;
+LL ~     use crate::two::Two;
+   |
+
+error[E0603]: struct import `One` is private
+  --> $DIR/private-import-grouped-suggestion-157453.rs:15:22
+   |
+LL |     use crate::two::{One};
+   |                      ^^^ private struct import
+   |
+note: the struct import `One` is defined here...
+  --> $DIR/private-import-grouped-suggestion-157453.rs:6:9
+   |
+LL |     use crate::one::One;
+   |         ^^^^^^^^^^^^^^^
+note: ...and refers to the struct `One` which is defined here
+  --> $DIR/private-import-grouped-suggestion-157453.rs:2:5
+   |
+LL |     pub struct One();
+   |     ^^^^^^^^^^^^^^^^^ you could import this directly
+help: import `One` directly
+   |
+LL -     use crate::two::{One};
+LL +     use crate::one::One;
+   |
+
+error[E0603]: struct import `MyPath` is private
+  --> $DIR/private-import-grouped-suggestion-157453.rs:29:27
+   |
+LL |     use crate::reexport::{MyPath};
+   |                           ^^^^^^ private struct import
+   |
+note: the struct import `MyPath` is defined here...
+  --> $DIR/private-import-grouped-suggestion-157453.rs:25:9
+   |
+LL |     use crate::outer::inner::MyPath;
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+note: ...and refers to the struct `MyPath` which is defined here
+  --> $DIR/private-import-grouped-suggestion-157453.rs:20:9
+   |
+LL |         pub struct MyPath;
+   |         ^^^^^^^^^^^^^^^^^^ you could import this directly
+help: import `MyPath` directly
+   |
+LL -     use crate::reexport::{MyPath};
+LL +     use crate::outer::inner::MyPath;
+   |
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0603`.

tests/ui/imports/private-import-nested-suggestion-156060.stderr

@@ -14,6 +14,11 @@ note: ...and refers to the struct `One` which is defined here
    |
 LL |     pub struct One();
    |     ^^^^^^^^^^^^^^^^^ you could import this directly
+help: import `One` directly
+   |
+LL ~     use crate::one::One;
+LL ~     use crate::two::Two;
+   |
 
 error: aborting due to 1 previous error
 

tests/ui/imports/private-import-suggestion-path-156244.edition_2015.stderr

@@ -36,6 +36,11 @@ note: ...and refers to the struct `One` which is defined here
    |
 LL |     pub struct One;
    |     ^^^^^^^^^^^^^^^ you could import this directly
+help: import `One` directly
+   |
+LL ~     use crate::a::One;
+LL ~     use crate::b::Two;
+   |
 
 error[E0603]: struct import `Two` is private
   --> $DIR/private-import-suggestion-path-156244.rs:35:25
@@ -53,6 +58,11 @@ note: ...and refers to the struct `Two` which is defined here
    |
 LL |     pub struct Two;
    |     ^^^^^^^^^^^^^^^ you could import this directly
+help: import `Two` directly
+   |
+LL ~     use crate::a::Two;
+LL ~     use crate::b::One;
+   |
 
 error[E0603]: module import `inner` is private
   --> $DIR/private-import-suggestion-path-156244.rs:38:24

tests/ui/imports/private-import-suggestion-path-156244.edition_2018.stderr

@@ -36,6 +36,11 @@ note: ...and refers to the struct `One` which is defined here
    |
 LL |     pub struct One;
    |     ^^^^^^^^^^^^^^^ you could import this directly
+help: import `One` directly
+   |
+LL ~     use crate::a::One;
+LL ~     use crate::b::Two;
+   |
 
 error[E0603]: struct import `Two` is private
   --> $DIR/private-import-suggestion-path-156244.rs:35:25
@@ -53,6 +58,11 @@ note: ...and refers to the struct `Two` which is defined here
    |
 LL |     pub struct Two;
    |     ^^^^^^^^^^^^^^^ you could import this directly
+help: import `Two` directly
+   |
+LL ~     use crate::a::Two;
+LL ~     use crate::b::One;
+   |
 
 error[E0603]: module import `inner` is private
   --> $DIR/private-import-suggestion-path-156244.rs:38:24