vis note for no pub reexports glob import

Author: bvanjoi

compiler/rustc_middle/src/ty/mod.rs

@@ -179,6 +179,7 @@ pub struct ResolverGlobalCtxt {
     pub doc_link_resolutions: FxHashMap<LocalDefId, DocLinkResMap>,
     pub doc_link_traits_in_scope: FxHashMap<LocalDefId, Vec<DefId>>,
     pub all_macro_rules: FxHashMap<Symbol, Res<ast::NodeId>>,
+    pub insufficient_vis: Vec<(LocalDefId, ty::Visibility)>,
 }
 
 /// Resolutions that should only be used for lowering.

compiler/rustc_privacy/messages.ftl

@@ -5,6 +5,10 @@ privacy_field_is_private_label = private field
 privacy_from_private_dep_in_public_interface =
     {$kind} `{$descr}` from private dependency '{$krate}' in public interface
 
+privacy_glob_import_doesnt_reexport =
+    glob import doesn't reexport anything because no candidate is public enough
+    .note = the most public imported item is `{$max_vis}`
+
 privacy_in_public_interface = {$vis_descr} {$kind} `{$descr}` in public interface
     .label = can't leak {$vis_descr} {$kind}
     .visibility_label = `{$descr}` declared as {$vis_descr}

compiler/rustc_privacy/src/errors.rs

@@ -104,3 +104,10 @@ pub struct PrivateInterfacesOrBoundsLint<'a> {
     pub ty_descr: DiagnosticArgFromDisplay<'a>,
     pub ty_vis_descr: &'a str,
 }
+
+#[derive(LintDiagnostic)]
+#[diag(privacy_glob_import_doesnt_reexport)]
+#[note]
+pub struct InsufficientVisibility {
+    pub max_vis: String,
+}

compiler/rustc_privacy/src/lib.rs

@@ -45,8 +45,8 @@ use std::{fmt, mem};
 
 use errors::{
     FieldIsPrivate, FieldIsPrivateLabel, FromPrivateDependencyInPublicInterface, InPublicInterface,
-    ItemIsPrivate, PrivateInterfacesOrBoundsLint, ReportEffectiveVisibility, UnnameableTypesLint,
-    UnnamedItemIsPrivate,
+    InsufficientVisibility, ItemIsPrivate, PrivateInterfacesOrBoundsLint,
+    ReportEffectiveVisibility, UnnameableTypesLint, UnnamedItemIsPrivate,
 };
 
 fluent_messages! { "../messages.ftl" }
@@ -1935,4 +1935,17 @@ fn check_private_in_public(tcx: TyCtxt<'_>, (): ()) {
     for id in tcx.hir().items() {
         checker.check_item(id);
     }
+
+    report_insufficient_visibility(tcx);
+}
+
+fn report_insufficient_visibility(tcx: TyCtxt<'_>) {
+    for (def_id, vis) in &tcx.resolutions(()).insufficient_vis {
+        tcx.emit_spanned_lint(
+            lint::builtin::UNUSED_IMPORTS,
+            tcx.hir().local_def_id_to_hir_id(*def_id),
+            tcx.def_span(def_id.to_def_id()),
+            InsufficientVisibility { max_vis: vis_to_string(*def_id, *vis, tcx) },
+        );
+    }
 }

compiler/rustc_resolve/messages.ftl

@@ -127,9 +127,6 @@ resolve_generic_params_from_outer_item_self_ty_param = can't use `Self` here
 
 resolve_generic_params_from_outer_item_ty_param = type parameter from outer item
 
-resolve_glob_import_doesnt_reexport =
-    glob import doesn't reexport anything because no candidate is public enough
-
 resolve_ident_bound_more_than_once_in_parameter_list =
     identifier `{$identifier}` is bound more than once in this parameter list
     .label = used as parameter more than once

compiler/rustc_resolve/src/imports.rs

@@ -8,7 +8,7 @@ use crate::errors::{
     ItemsInTraitsAreNotImportable,
 };
 use crate::Determinacy::{self, *};
-use crate::{fluent_generated as fluent, Namespace::*};
+use crate::Namespace::*;
 use crate::{module_to_string, names_to_string, ImportSuggestion};
 use crate::{AmbiguityKind, BindingKey, ModuleKind, ResolutionError, Resolver, Segment};
 use crate::{Finalize, Module, ModuleOrUniformRoot, ParentScope, PerNS, ScopeSet};
@@ -989,12 +989,8 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                         && let Some(max_vis) = max_vis.get()
                         && !max_vis.is_at_least(import.expect_vis(), self.tcx)
                     {
-                        self.lint_buffer.buffer_lint(
-                            UNUSED_IMPORTS,
-                            id,
-                            import.span,
-                            fluent::resolve_glob_import_doesnt_reexport,
-                        );
+                        let def_id = self.local_def_id(id);
+                        self.insufficient_vis.push((def_id, max_vis));
                     }
                     return None;
                 }

compiler/rustc_resolve/src/lib.rs

@@ -958,6 +958,8 @@ pub struct Resolver<'a, 'tcx> {
     /// All non-determined imports.
     indeterminate_imports: Vec<Import<'a>>,
 
+    insufficient_vis: Vec<(LocalDefId, ty::Visibility)>,
+
     // Spans for local variables found during pattern resolution.
     // Used for suggestions during error reporting.
     pat_span_map: NodeMap<Span>,
@@ -1340,6 +1342,8 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
             determined_imports: Vec::new(),
             indeterminate_imports: Vec::new(),
 
+            insufficient_vis: Vec::new(),
+
             pat_span_map: Default::default(),
             partial_res_map: Default::default(),
             import_res_map: Default::default(),
@@ -1525,6 +1529,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
             doc_link_resolutions: self.doc_link_resolutions,
             doc_link_traits_in_scope: self.doc_link_traits_in_scope,
             all_macro_rules: self.all_macro_rules,
+            insufficient_vis: self.insufficient_vis,
         };
         let ast_lowering = ty::ResolverAstLowering {
             legacy_const_generic_args: self.legacy_const_generic_args,

tests/ui/imports/no-reexports-but-used.rs

@@ -0,0 +1,14 @@
+// run-pass
+// https://github.com/rust-lang/rust/issues/115966
+
+mod m {
+    pub(crate) type A = u8;
+}
+
+pub use m::*;
+//~^ WARNING: glob import doesn't reexport anything because no candidate is public enough
+//~| NOTE: the most public imported item is `pub(crate)`
+//~| NOTE: #[warn(unused_imports)]` on by default
+fn main() {
+    let _: A;
+}

tests/ui/imports/no-reexports-but-used.stderr

@@ -0,0 +1,11 @@
+warning: glob import doesn't reexport anything because no candidate is public enough
+  --> $DIR/no-reexports-but-used.rs:8:9
+   |
+LL | pub use m::*;
+   |         ^
+   |
+   = note: the most public imported item is `pub(crate)`
+   = note: `#[warn(unused_imports)]` on by default
+
+warning: 1 warning emitted
+

tests/ui/imports/reexports.rs

@@ -9,8 +9,7 @@ mod a {
         //~^ ERROR cannot be re-exported
         //~| WARNING unused import: `super::foo`
         pub use super::*;
-        //~^ WARNING glob import doesn't reexport anything because no candidate is public enough
-        //~| WARNING unused import: `super::*`
+        //~^ WARNING unused import: `super::*`
     }
 }