blob: be77d049cae40db8555103a6ec472f39ef056725 [file] [log] [blame]
use rustc_errors::struct_span_err;
use rustc_hir as hir;
use rustc_hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
use rustc_hir::itemlikevisit::ItemLikeVisitor;
use rustc_middle::ty::TyCtxt;
use rustc_trait_selection::traits::{self, SkipLeakCheck};
pub fn crate_inherent_impls_overlap_check(tcx: TyCtxt<'_>, crate_num: CrateNum) {
assert_eq!(crate_num, LOCAL_CRATE);
let krate = tcx.hir().krate();
krate.visit_all_item_likes(&mut InherentOverlapChecker { tcx });
}
struct InherentOverlapChecker<'tcx> {
tcx: TyCtxt<'tcx>,
}
impl InherentOverlapChecker<'tcx> {
/// Checks whether any associated items in impls 1 and 2 share the same identifier and
/// namespace.
fn impls_have_common_items(&self, impl1: DefId, impl2: DefId) -> bool {
let impl_items1 = self.tcx.associated_items(impl1);
let impl_items2 = self.tcx.associated_items(impl2);
for item1 in impl_items1.in_definition_order() {
let collision = impl_items2.filter_by_name_unhygienic(item1.ident.name).any(|item2| {
// Symbols and namespace match, compare hygienically.
item1.kind.namespace() == item2.kind.namespace()
&& item1.ident.normalize_to_macros_2_0()
== item2.ident.normalize_to_macros_2_0()
});
if collision {
return true;
}
}
false
}
fn check_for_common_items_in_impls(
&self,
impl1: DefId,
impl2: DefId,
overlap: traits::OverlapResult<'_>,
) {
let impl_items1 = self.tcx.associated_items(impl1);
let impl_items2 = self.tcx.associated_items(impl2);
for item1 in impl_items1.in_definition_order() {
let collision = impl_items2.filter_by_name_unhygienic(item1.ident.name).find(|item2| {
// Symbols and namespace match, compare hygienically.
item1.kind.namespace() == item2.kind.namespace()
&& item1.ident.normalize_to_macros_2_0()
== item2.ident.normalize_to_macros_2_0()
});
if let Some(item2) = collision {
let name = item1.ident.normalize_to_macros_2_0();
let mut err = struct_span_err!(
self.tcx.sess,
self.tcx.span_of_impl(item1.def_id).unwrap(),
E0592,
"duplicate definitions with name `{}`",
name
);
err.span_label(
self.tcx.span_of_impl(item1.def_id).unwrap(),
format!("duplicate definitions for `{}`", name),
);
err.span_label(
self.tcx.span_of_impl(item2.def_id).unwrap(),
format!("other definition for `{}`", name),
);
for cause in &overlap.intercrate_ambiguity_causes {
cause.add_intercrate_ambiguity_hint(&mut err);
}
if overlap.involves_placeholder {
traits::add_placeholder_note(&mut err);
}
err.emit();
}
}
}
fn check_for_overlapping_inherent_impls(&self, impl1_def_id: DefId, impl2_def_id: DefId) {
traits::overlapping_impls(
self.tcx,
impl1_def_id,
impl2_def_id,
// We go ahead and just skip the leak check for
// inherent impls without warning.
SkipLeakCheck::Yes,
|overlap| {
self.check_for_common_items_in_impls(impl1_def_id, impl2_def_id, overlap);
false
},
|| true,
);
}
}
impl ItemLikeVisitor<'v> for InherentOverlapChecker<'tcx> {
fn visit_item(&mut self, item: &'v hir::Item<'v>) {
match item.kind {
hir::ItemKind::Enum(..)
| hir::ItemKind::Struct(..)
| hir::ItemKind::Trait(..)
| hir::ItemKind::Union(..) => {
let ty_def_id = self.tcx.hir().local_def_id(item.hir_id);
let impls = self.tcx.inherent_impls(ty_def_id);
for (i, &impl1_def_id) in impls.iter().enumerate() {
for &impl2_def_id in &impls[(i + 1)..] {
if self.impls_have_common_items(impl1_def_id, impl2_def_id) {
self.check_for_overlapping_inherent_impls(impl1_def_id, impl2_def_id);
}
}
}
}
_ => {}
}
}
fn visit_trait_item(&mut self, _trait_item: &hir::TraitItem<'v>) {}
fn visit_impl_item(&mut self, _impl_item: &hir::ImplItem<'v>) {}
}