bendns' repos / rust-analyzer
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Diffstat (limited to 'crates/hir-ty/src/method_resolution.rs')
-rw-r--r--crates/hir-ty/src/method_resolution.rs56
1 files changed, 56 insertions, 0 deletions
diff --git a/crates/hir-ty/src/method_resolution.rs b/crates/hir-ty/src/method_resolution.rs
index f3a5f69b2a..87c9328336 100644
--- a/crates/hir-ty/src/method_resolution.rs
+++ b/crates/hir-ty/src/method_resolution.rs
@@ -862,6 +862,62 @@ fn is_inherent_impl_coherent(
}
}
+/// Checks whether the impl satisfies the orphan rules.
+///
+/// Given `impl<P1..=Pn> Trait<T1..=Tn> for T0`, an `impl`` is valid only if at least one of the following is true:
+/// - Trait is a local trait
+/// - All of
+/// - At least one of the types `T0..=Tn`` must be a local type. Let `Ti`` be the first such type.
+/// - No uncovered type parameters `P1..=Pn` may appear in `T0..Ti`` (excluding `Ti`)
+pub fn check_orphan_rules(db: &dyn HirDatabase, impl_: ImplId) -> bool {
+ let substs = TyBuilder::placeholder_subst(db, impl_);
+ let Some(impl_trait) = db.impl_trait(impl_) else {
+ // not a trait impl
+ return true;
+ };
+
+ let local_crate = impl_.lookup(db.upcast()).container.krate();
+ let is_local = |tgt_crate| tgt_crate == local_crate;
+
+ let trait_ref = impl_trait.substitute(Interner, &substs);
+ let trait_id = from_chalk_trait_id(trait_ref.trait_id);
+ if is_local(trait_id.module(db.upcast()).krate()) {
+ // trait to be implemented is local
+ return true;
+ }
+
+ let unwrap_fundamental = |ty: Ty| match ty.kind(Interner) {
+ TyKind::Ref(_, _, referenced) => referenced.clone(),
+ &TyKind::Adt(AdtId(hir_def::AdtId::StructId(s)), ref subs) => {
+ let struct_data = db.struct_data(s);
+ if struct_data.flags.contains(StructFlags::IS_FUNDAMENTAL) {
+ let next = subs.type_parameters(Interner).next();
+ match next {
+ Some(ty) => ty,
+ None => ty,
+ }
+ } else {
+ ty
+ }
+ }
+ _ => ty,
+ };
+ // - At least one of the types `T0..=Tn`` must be a local type. Let `Ti`` be the first such type.
+ let is_not_orphan = trait_ref.substitution.type_parameters(Interner).any(|ty| {
+ match unwrap_fundamental(ty).kind(Interner) {
+ &TyKind::Adt(AdtId(id), _) => is_local(id.module(db.upcast()).krate()),
+ TyKind::Error => true,
+ TyKind::Dyn(it) => it.principal().map_or(false, |trait_ref| {
+ is_local(from_chalk_trait_id(trait_ref.trait_id).module(db.upcast()).krate())
+ }),
+ _ => false,
+ }
+ });
+ // FIXME: param coverage
+ // - No uncovered type parameters `P1..=Pn` may appear in `T0..Ti`` (excluding `Ti`)
+ is_not_orphan
+}
+
pub fn iterate_path_candidates(
ty: &Canonical<Ty>,
db: &dyn HirDatabase,