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Use relative visibility when noting sealed trait to reduce false positive

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Signed-off-by: xizheyin <xizheyin@smail.nju.edu.cn>
This commit is contained in:
xizheyin 2025-07-04 21:38:46 +08:00
parent 2111525850
commit 4a261a1513
3 changed files with 17 additions and 8 deletions
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20
compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
View file

@ -22,6 +22,7 @@ use rustc_hir::{
expr_needs_parens, is_range_literal,
};
use rustc_infer::infer::{BoundRegionConversionTime, DefineOpaqueTypes, InferCtxt, InferOk};
use rustc_middle::middle::privacy::Level;
use rustc_middle::traits::IsConstable;
use rustc_middle::ty::error::TypeError;
use rustc_middle::ty::print::{
@ -2775,11 +2776,20 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
ty::ClauseKind::Trait(trait_pred) => {
let def_id = trait_pred.def_id();
let visible_item = if let Some(local) = def_id.as_local() {
// Check for local traits being reachable.
let vis = &tcx.resolutions(()).effective_visibilities;
// Account for non-`pub` traits in the root of the local crate.
let is_locally_reachable = tcx.parent(def_id).is_crate_root();
vis.is_reachable(local) || is_locally_reachable
let ty = trait_pred.self_ty();
// when `TraitA: TraitB` and `S` only impl TraitA,
// we check if `TraitB` can be reachable from `S`
// to determine whether to note `TraitA` is sealed trait.
if let ty::Adt(adt, _) = ty.kind() {
let visibilities = tcx.effective_visibilities(());
visibilities.effective_vis(local).is_none_or(|v| {
v.at_level(Level::Reexported)
.is_accessible_from(adt.did(), tcx)
})
} else {
// FIXME(xizheyin): if the type is not ADT, we should not suggest it
true
}
} else {
// Check for foreign traits being reachable.
tcx.visible_parent_map(()).get(&def_id).is_some()

4
tests/ui/privacy/sealed-traits/false-sealed-traits-note.rs
View file

@ -1,4 +1,4 @@
// when we impl TraitA for Struct, it can compile, we should not emit sealed traits note, see issue #143392
// We should not emit sealed traits note, see issue #143392
mod inner {
pub trait TraitA {}
@ -10,4 +10,4 @@ struct Struct;
impl inner::TraitB for Struct {} //~ ERROR the trait bound `Struct: TraitA` is not satisfied [E0277]
fn main(){}
fn main(){}

1
tests/ui/privacy/sealed-traits/false-sealed-traits-note.stderr
View file

@ -14,7 +14,6 @@ note: required by a bound in `TraitB`
|
LL | pub trait TraitB: TraitA {}
| ^^^^^^ required by this bound in `TraitB`
= note: `TraitB` is a "sealed trait", because to implement it you also need to implement `inner::TraitA`, which is not accessible; this is usually done to force you to use one of the provided types that already implement it
error: aborting due to 1 previous error