Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/hir-ty/src/lower.rs')
| -rw-r--r-- | crates/hir-ty/src/lower.rs | 38 |
1 files changed, 30 insertions, 8 deletions
diff --git a/crates/hir-ty/src/lower.rs b/crates/hir-ty/src/lower.rs index 9befca11b3..5789bf02a4 100644 --- a/crates/hir-ty/src/lower.rs +++ b/crates/hir-ty/src/lower.rs @@ -53,7 +53,7 @@ use tracing::debug; use triomphe::{Arc, ThinArc}; use crate::{ - FnAbi, ImplTraitId, TyLoweringDiagnostic, TyLoweringDiagnosticKind, + FnAbi, ImplTraitId, TyLoweringDiagnostic, TyLoweringDiagnosticKind, all_super_traits, consteval::intern_const_ref, db::{HirDatabase, InternedOpaqueTyId}, generics::{Generics, generics, trait_self_param_idx}, @@ -1624,11 +1624,16 @@ pub(crate) fn field_types_with_diagnostics_query<'db>( (res, create_diagnostics(ctx.diagnostics)) } +/// Predicates for `param_id` of the form `P: SomeTrait`. If +/// `assoc_name` is provided, only return predicates referencing traits +/// that have an associated type of that name. +/// /// This query exists only to be used when resolving short-hand associated types /// like `T::Item`. /// /// See the analogous query in rustc and its comment: /// <https://github.com/rust-lang/rust/blob/9150f844e2624eb013ec78ca08c1d416e6644026/src/librustc_typeck/astconv.rs#L46> +/// /// This is a query mostly to handle cycles somewhat gracefully; e.g. the /// following bounds are disallowed: `T: Foo<U::Item>, U: Foo<T::Item>`, but /// these are fine: `T: Foo<U::Item>, U: Foo<()>`. @@ -1652,7 +1657,7 @@ pub(crate) fn generic_predicates_for_param<'db>( ); // we have to filter out all other predicates *first*, before attempting to lower them - let predicate = |pred: &_, ctx: &mut TyLoweringContext<'_, '_>| match pred { + let has_relevant_bound = |pred: &_, ctx: &mut TyLoweringContext<'_, '_>| match pred { WherePredicate::ForLifetime { target, bound, .. } | WherePredicate::TypeBound { target, bound, .. } => { let invalid_target = { ctx.lower_ty_only_param(*target) != Some(param_id) }; @@ -1700,11 +1705,7 @@ pub(crate) fn generic_predicates_for_param<'db>( return false; }; - rustc_type_ir::elaborate::supertrait_def_ids(interner, tr.into()).any(|tr| { - tr.0.trait_items(db).items.iter().any(|(name, item)| { - matches!(item, AssocItemId::TypeAliasId(_)) && name == assoc_name - }) - }) + trait_or_supertrait_has_assoc_type(db, tr, assoc_name) } TypeBound::Use(_) | TypeBound::Lifetime(_) | TypeBound::Error => false, } @@ -1717,7 +1718,7 @@ pub(crate) fn generic_predicates_for_param<'db>( { ctx.store = maybe_parent_generics.store(); for pred in maybe_parent_generics.where_predicates() { - if predicate(pred, &mut ctx) { + if has_relevant_bound(pred, &mut ctx) { predicates.extend( ctx.lower_where_predicate( pred, @@ -1757,6 +1758,27 @@ pub(crate) fn generic_predicates_for_param_cycle_result( StoredEarlyBinder::bind(Clauses::empty(DbInterner::new_no_crate(db)).store()) } +/// Check if this trait or any of its supertraits define an associated +/// type with the given name. +fn trait_or_supertrait_has_assoc_type( + db: &dyn HirDatabase, + tr: TraitId, + assoc_name: &Name, +) -> bool { + for trait_id in all_super_traits(db, tr) { + if trait_id + .trait_items(db) + .items + .iter() + .any(|(name, item)| matches!(item, AssocItemId::TypeAliasId(_)) && name == assoc_name) + { + return true; + } + } + + false +} + #[inline] pub(crate) fn type_alias_bounds<'db>( db: &'db dyn HirDatabase, |