⬆️ rust-analyzer

crates/hir-ty/src/db.rs

@@ -150,6 +150,14 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
         id: chalk_db::AssociatedTyValueId,
     ) -> Arc<chalk_db::AssociatedTyValue>;
 
+    #[salsa::invoke(crate::traits::normalize_projection_query)]
+    #[salsa::transparent]
+    fn normalize_projection(
+        &self,
+        projection: crate::ProjectionTy,
+        env: Arc<crate::TraitEnvironment>,
+    ) -> Ty;
+
     #[salsa::invoke(trait_solve_wait)]
     #[salsa::transparent]
     fn trait_solve(

crates/hir-ty/src/display.rs

@@ -533,6 +533,7 @@ impl HirDisplay for Ty {
                             f.db.upcast(),
                             ItemInNs::Types((*def_id).into()),
                             module_id,
+                            false,
                         ) {
                             write!(f, "{}", path)?;
                         } else {

crates/hir-ty/src/infer.rs

@@ -673,10 +673,6 @@ impl<'a> InferenceContext<'a> {
         )
     }
 
-    fn resolve_obligations_as_possible(&mut self) {
-        self.table.resolve_obligations_as_possible();
-    }
-
     fn push_obligation(&mut self, o: DomainGoal) {
         self.table.register_obligation(o.cast(Interner));
     }
@@ -696,7 +692,6 @@ impl<'a> InferenceContext<'a> {
     }
 
     fn resolve_ty_shallow(&mut self, ty: &Ty) -> Ty {
-        self.resolve_obligations_as_possible();
         self.table.resolve_ty_shallow(ty)
     }
 

crates/hir-ty/src/lib.rs

@@ -196,20 +196,6 @@ pub(crate) fn make_binders<T: HasInterner<Interner = Interner>>(
     make_binders_with_count(db, usize::MAX, generics, value)
 }
 
-// FIXME: get rid of this
-pub fn make_canonical<T: HasInterner<Interner = Interner>>(
-    value: T,
-    kinds: impl IntoIterator<Item = TyVariableKind>,
-) -> Canonical<T> {
-    let kinds = kinds.into_iter().map(|tk| {
-        chalk_ir::CanonicalVarKind::new(
-            chalk_ir::VariableKind::Ty(tk),
-            chalk_ir::UniverseIndex::ROOT,
-        )
-    });
-    Canonical { value, binders: chalk_ir::CanonicalVarKinds::from_iter(Interner, kinds) }
-}
-
 // FIXME: get rid of this, just replace it by FnPointer
 /// A function signature as seen by type inference: Several parameter types and
 /// one return type.

crates/hir-ty/src/method_resolution.rs

@@ -914,22 +914,10 @@ fn iterate_trait_method_candidates(
     let db = table.db;
     let env = table.trait_env.clone();
     let self_is_array = matches!(self_ty.kind(Interner), chalk_ir::TyKind::Array(..));
-    // if ty is `dyn Trait`, the trait doesn't need to be in scope
-    let inherent_trait =
-        self_ty.dyn_trait().into_iter().flat_map(|t| all_super_traits(db.upcast(), t));
-    let env_traits = matches!(self_ty.kind(Interner), TyKind::Placeholder(_))
-        // if we have `T: Trait` in the param env, the trait doesn't need to be in scope
-        .then(|| {
-            env.traits_in_scope_from_clauses(self_ty.clone())
-                .flat_map(|t| all_super_traits(db.upcast(), t))
-        })
-        .into_iter()
-        .flatten();
-    let traits = inherent_trait.chain(env_traits).chain(traits_in_scope.iter().copied());
 
     let canonical_self_ty = table.canonicalize(self_ty.clone()).value;
 
-    'traits: for t in traits {
+    'traits: for &t in traits_in_scope {
         let data = db.trait_data(t);
 
         // Traits annotated with `#[rustc_skip_array_during_method_dispatch]` are skipped during
@@ -979,6 +967,44 @@ fn iterate_inherent_methods(
 ) -> ControlFlow<()> {
     let db = table.db;
     let env = table.trait_env.clone();
+
+    // For trait object types and placeholder types with trait bounds, the methods of the trait and
+    // its super traits are considered inherent methods. This matters because these methods have
+    // higher priority than the other traits' methods, which would be considered in
+    // `iterate_trait_method_candidates()` only after this function.
+    match self_ty.kind(Interner) {
+        TyKind::Placeholder(_) => {
+            let env = table.trait_env.clone();
+            let traits = env
+                .traits_in_scope_from_clauses(self_ty.clone())
+                .flat_map(|t| all_super_traits(db.upcast(), t));
+            iterate_inherent_trait_methods(
+                self_ty,
+                table,
+                name,
+                receiver_ty,
+                receiver_adjustments.clone(),
+                callback,
+                traits,
+            )?;
+        }
+        TyKind::Dyn(_) => {
+            if let Some(principal_trait) = self_ty.dyn_trait() {
+                let traits = all_super_traits(db.upcast(), principal_trait);
+                iterate_inherent_trait_methods(
+                    self_ty,
+                    table,
+                    name,
+                    receiver_ty,
+                    receiver_adjustments.clone(),
+                    callback,
+                    traits.into_iter(),
+                )?;
+            }
+        }
+        _ => {}
+    }
+
     let def_crates = match def_crates(db, self_ty, env.krate) {
         Some(k) => k,
         None => return ControlFlow::Continue(()),
@@ -1020,6 +1046,28 @@ fn iterate_inherent_methods(
     }
     return ControlFlow::Continue(());
 
+    fn iterate_inherent_trait_methods(
+        self_ty: &Ty,
+        table: &mut InferenceTable<'_>,
+        name: Option<&Name>,
+        receiver_ty: Option<&Ty>,
+        receiver_adjustments: Option<ReceiverAdjustments>,
+        callback: &mut dyn FnMut(ReceiverAdjustments, AssocItemId) -> ControlFlow<()>,
+        traits: impl Iterator<Item = TraitId>,
+    ) -> ControlFlow<()> {
+        let db = table.db;
+        for t in traits {
+            let data = db.trait_data(t);
+            for &(_, item) in data.items.iter() {
+                // We don't pass `visible_from_module` as all trait items should be visible.
+                if is_valid_candidate(table, name, receiver_ty, item, self_ty, None) {
+                    callback(receiver_adjustments.clone().unwrap_or_default(), item)?;
+                }
+            }
+        }
+        ControlFlow::Continue(())
+    }
+
     fn impls_for_self_ty(
         impls: &InherentImpls,
         self_ty: &Ty,

crates/hir-ty/src/tests/method_resolution.rs

@@ -1218,6 +1218,40 @@ fn main() {
     );
 }
 
+#[test]
+fn dyn_trait_method_priority() {
+    check_types(
+        r#"
+//- minicore: from
+trait Trait {
+    fn into(&self) -> usize { 0 }
+}
+
+fn foo(a: &dyn Trait) {
+    let _ = a.into();
+      //^usize
+}
+        "#,
+    );
+}
+
+#[test]
+fn trait_method_priority_for_placeholder_type() {
+    check_types(
+        r#"
+//- minicore: from
+trait Trait {
+    fn into(&self) -> usize { 0 }
+}
+
+fn foo<T: Trait>(a: &T) {
+    let _ = a.into();
+      //^usize
+}
+        "#,
+    );
+}
+
 #[test]
 fn autoderef_visibility_field() {
     check(

crates/hir-ty/src/traits.rs

@@ -1,6 +1,6 @@
 //! Trait solving using Chalk.
 
-use std::env::var;
+use std::{env::var, sync::Arc};
 
 use chalk_ir::GoalData;
 use chalk_recursive::Cache;
@@ -12,8 +12,9 @@ use stdx::panic_context;
 use syntax::SmolStr;
 
 use crate::{
-    db::HirDatabase, AliasEq, AliasTy, Canonical, DomainGoal, Goal, Guidance, InEnvironment,
-    Interner, Solution, TraitRefExt, Ty, TyKind, WhereClause,
+    db::HirDatabase, infer::unify::InferenceTable, AliasEq, AliasTy, Canonical, DomainGoal, Goal,
+    Guidance, InEnvironment, Interner, ProjectionTy, Solution, TraitRefExt, Ty, TyKind,
+    WhereClause,
 };
 
 /// This controls how much 'time' we give the Chalk solver before giving up.
@@ -64,6 +65,16 @@ impl TraitEnvironment {
     }
 }
 
+pub(crate) fn normalize_projection_query(
+    db: &dyn HirDatabase,
+    projection: ProjectionTy,
+    env: Arc<TraitEnvironment>,
+) -> Ty {
+    let mut table = InferenceTable::new(db, env);
+    let ty = table.normalize_projection_ty(projection);
+    table.resolve_completely(ty)
+}
+
 /// Solve a trait goal using Chalk.
 pub(crate) fn trait_solve_query(
     db: &dyn HirDatabase,