Merge #2413

2413: Remove another helper r=matklad a=matklad



Co-authored-by: Aleksey Kladov <[email protected]>

6 files changed, 115 insertions, 48 deletions

diff --git a/crates/ra_hir/src/ty/autoderef.rs b/crates/ra_hir/src/ty/autoderef.rs
index 9e7593b8b..ae68234ac 100644
--- a/crates/ra_hir/src/ty/autoderef.rs
+++ b/crates/ra_hir/src/ty/autoderef.rs
@@ -10,7 +10,7 @@ use hir_expand::name;
 use log::{info, warn};
 use ra_db::CrateId;
 
-use crate::{db::HirDatabase, Trait};
+use crate::db::HirDatabase;
 
 use super::{
     traits::{InEnvironment, Solution},
@@ -49,12 +49,12 @@ fn deref_by_trait(
     ty: InEnvironment<&Canonical<Ty>>,
 ) -> Option<Canonical<Ty>> {
     let deref_trait = match db.lang_item(krate.into(), "deref".into())? {
-        LangItemTarget::TraitId(t) => Trait::from(t),
+        LangItemTarget::TraitId(it) => it,
         _ => return None,
     };
-    let target = deref_trait.associated_type_by_name(db, &name::TARGET_TYPE)?;
+    let target = db.trait_data(deref_trait).associated_type_by_name(&name::TARGET_TYPE)?;
 
-    let generic_params = db.generic_params(target.id.into());
+    let generic_params = db.generic_params(target.into());
     if generic_params.count_params_including_parent() != 1 {
         // the Target type + Deref trait should only have one generic parameter,
         // namely Deref's Self type
@@ -69,7 +69,7 @@ fn deref_by_trait(
 
     let projection = super::traits::ProjectionPredicate {
         ty: Ty::Bound(0),
-        projection_ty: super::ProjectionTy { associated_ty: target.id, parameters },
+        projection_ty: super::ProjectionTy { associated_ty: target, parameters },
     };
 
     let obligation = super::Obligation::Projection(projection);
diff --git a/crates/ra_hir/src/ty/infer.rs b/crates/ra_hir/src/ty/infer.rs
index fce45321d..b023ae690 100644
--- a/crates/ra_hir/src/ty/infer.rs
+++ b/crates/ra_hir/src/ty/infer.rs
@@ -43,7 +43,7 @@ use crate::{
     db::HirDatabase,
     expr::{BindingAnnotation, Body, ExprId, PatId},
     ty::infer::diagnostics::InferenceDiagnostic,
-    Adt, AssocItem, DefWithBody, FloatTy, Function, IntTy, Path, StructField, Trait, VariantDef,
+    Adt, AssocItem, DefWithBody, FloatTy, Function, IntTy, Path, StructField, VariantDef,
 };
 
 macro_rules! ty_app {
@@ -582,20 +582,20 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
 
     fn resolve_into_iter_item(&self) -> Option<TypeAlias> {
         let path = known::std_iter_into_iterator();
-        let trait_: Trait = self.resolver.resolve_known_trait(self.db, &path)?.into();
-        trait_.associated_type_by_name(self.db, &name::ITEM_TYPE)
+        let trait_ = self.resolver.resolve_known_trait(self.db, &path)?;
+        self.db.trait_data(trait_).associated_type_by_name(&name::ITEM_TYPE).map(TypeAlias::from)
     }
 
     fn resolve_ops_try_ok(&self) -> Option<TypeAlias> {
         let path = known::std_ops_try();
-        let trait_: Trait = self.resolver.resolve_known_trait(self.db, &path)?.into();
-        trait_.associated_type_by_name(self.db, &name::OK_TYPE)
+        let trait_ = self.resolver.resolve_known_trait(self.db, &path)?;
+        self.db.trait_data(trait_).associated_type_by_name(&name::OK_TYPE).map(TypeAlias::from)
     }
 
     fn resolve_future_future_output(&self) -> Option<TypeAlias> {
         let path = known::std_future_future();
-        let trait_: Trait = self.resolver.resolve_known_trait(self.db, &path)?.into();
-        trait_.associated_type_by_name(self.db, &name::OUTPUT_TYPE)
+        let trait_ = self.resolver.resolve_known_trait(self.db, &path)?;
+        self.db.trait_data(trait_).associated_type_by_name(&name::OUTPUT_TYPE).map(TypeAlias::from)
     }
 
     fn resolve_boxed_box(&self) -> Option<AdtId> {
diff --git a/crates/ra_hir/src/ty/lower.rs b/crates/ra_hir/src/ty/lower.rs
index 2d23890a5..805a73ff5 100644
--- a/crates/ra_hir/src/ty/lower.rs
+++ b/crates/ra_hir/src/ty/lower.rs
@@ -28,6 +28,7 @@ use crate::{
     db::HirDatabase,
     ty::{
         primitive::{FloatTy, IntTy},
+        utils::{all_super_traits, associated_type_by_name_including_super_traits},
         Adt,
     },
     util::make_mut_slice,
@@ -169,14 +170,16 @@ impl Ty {
                 );
                 return if remaining_segments.len() == 1 {
                     let segment = &remaining_segments[0];
-                    match trait_ref
-                        .trait_
-                        .associated_type_by_name_including_super_traits(db, &segment.name)
-                    {
+                    let associated_ty = associated_type_by_name_including_super_traits(
+                        db,
+                        trait_ref.trait_.id,
+                        &segment.name,
+                    );
+                    match associated_ty {
                         Some(associated_ty) => {
                             // FIXME handle type parameters on the segment
                             Ty::Projection(ProjectionTy {
-                                associated_ty: associated_ty.id,
+                                associated_ty,
                                 parameters: trait_ref.substs,
                             })
                         }
@@ -260,18 +263,16 @@ impl Ty {
             GenericPredicate::Implemented(tr) if tr.self_ty() == &self_ty => Some(tr.trait_),
             _ => None,
         });
-        let traits = traits_from_env.flat_map(|t| t.all_super_traits(db));
+        let traits = traits_from_env.flat_map(|t| all_super_traits(db, t.id)).map(Trait::from);
         for t in traits {
-            if let Some(associated_ty) = t.associated_type_by_name(db, &segment.name) {
+            if let Some(associated_ty) = db.trait_data(t.id).associated_type_by_name(&segment.name)
+            {
                 let substs = Substs::build_for_def(db, t.id)
                     .push(self_ty.clone())
                     .fill_with_unknown()
                     .build();
                 // FIXME handle type parameters on the segment
-                return Ty::Projection(ProjectionTy {
-                    associated_ty: associated_ty.id,
-                    parameters: substs,
-                });
+                return Ty::Projection(ProjectionTy { associated_ty, parameters: substs });
             }
         }
         Ty::Unknown
@@ -509,10 +510,11 @@ fn assoc_type_bindings_from_type_bound<'a>(
         .flat_map(|args_and_bindings| args_and_bindings.bindings.iter())
         .map(move |(name, type_ref)| {
             let associated_ty =
-                match trait_ref.trait_.associated_type_by_name_including_super_traits(db, &name) {
-                    None => return GenericPredicate::Error,
-                    Some(t) => t.id,
-                };
+                associated_type_by_name_including_super_traits(db, trait_ref.trait_.id, &name);
+            let associated_ty = match associated_ty {
+                None => return GenericPredicate::Error,
+                Some(t) => t,
+            };
             let projection_ty =
                 ProjectionTy { associated_ty, parameters: trait_ref.substs.clone() };
             let ty = Ty::from_hir(db, resolver, type_ref);
diff --git a/crates/ra_hir/src/ty/method_resolution.rs b/crates/ra_hir/src/ty/method_resolution.rs
index 489fcd64b..9988570e8 100644
--- a/crates/ra_hir/src/ty/method_resolution.rs
+++ b/crates/ra_hir/src/ty/method_resolution.rs
@@ -16,7 +16,7 @@ use rustc_hash::FxHashMap;
 use crate::{
     db::HirDatabase,
     ty::primitive::{FloatBitness, Uncertain},
-    ty::{Ty, TypeCtor},
+    ty::{utils::all_super_traits, Ty, TypeCtor},
     AssocItem, Crate, Function, Mutability, Name, Trait,
 };
 
@@ -249,7 +249,8 @@ fn iterate_trait_method_candidates<T>(
     let traits_from_env = env
         .trait_predicates_for_self_ty(&ty.value)
         .map(|tr| tr.trait_)
-        .flat_map(|t| t.all_super_traits(db));
+        .flat_map(|t| all_super_traits(db, t.id))
+        .map(Trait::from);
     let traits = inherent_trait
         .chain(traits_from_env)
         .chain(resolver.traits_in_scope(db).into_iter().map(Trait::from));
@@ -260,8 +261,8 @@ fn iterate_trait_method_candidates<T>(
         // trait, but if we find out it doesn't, we'll skip the rest of the
         // iteration
         let mut known_implemented = false;
-        for &item in data.items.iter() {
-            if !is_valid_candidate(db, name, mode, item.into()) {
+        for (_name, item) in data.items.iter() {
+            if !is_valid_candidate(db, name, mode, (*item).into()) {
                 continue;
             }
             if !known_implemented {
@@ -271,7 +272,7 @@ fn iterate_trait_method_candidates<T>(
                 }
             }
             known_implemented = true;
-            if let Some(result) = callback(&ty.value, item.into()) {
+            if let Some(result) = callback(&ty.value, (*item).into()) {
                 return Some(result);
             }
         }
diff --git a/crates/ra_hir/src/ty/traits/chalk.rs b/crates/ra_hir/src/ty/traits/chalk.rs
index 06388a3ce..78f4b3e27 100644
--- a/crates/ra_hir/src/ty/traits/chalk.rs
+++ b/crates/ra_hir/src/ty/traits/chalk.rs
@@ -9,7 +9,7 @@ use chalk_ir::{
 };
 use chalk_rust_ir::{AssociatedTyDatum, AssociatedTyValue, ImplDatum, StructDatum, TraitDatum};
 
-use hir_def::{lang_item::LangItemTarget, ContainerId, GenericDefId, Lookup, TypeAliasId};
+use hir_def::{lang_item::LangItemTarget, ContainerId, GenericDefId, Lookup, TraitId, TypeAliasId};
 use hir_expand::name;
 
 use ra_db::salsa::{InternId, InternKey};
@@ -459,7 +459,7 @@ where
                 [super::FnTrait::FnOnce, super::FnTrait::FnMut, super::FnTrait::Fn].iter()
             {
                 if let Some(actual_trait) = get_fn_trait(self.db, self.krate, fn_trait) {
-                    if trait_ == actual_trait {
+                    if trait_.id == actual_trait {
                         let impl_ = super::ClosureFnTraitImplData { def, expr, fn_trait };
                         result.push(Impl::ClosureFnTraitImpl(impl_).to_chalk(self.db));
                     }
@@ -661,6 +661,7 @@ fn impl_block_datum(
     };
 
     let impl_datum_bound = chalk_rust_ir::ImplDatumBound { trait_ref, where_clauses };
+    let trait_data = db.trait_data(trait_.id);
     let associated_ty_value_ids = impl_block
         .items(db)
         .into_iter()
@@ -670,7 +671,7 @@ fn impl_block_datum(
         })
         .filter(|type_alias| {
             // don't include associated types that don't exist in the trait
-            trait_.associated_type_by_name(db, &type_alias.name(db)).is_some()
+            trait_data.associated_type_by_name(&type_alias.name(db)).is_some()
         })
         .map(|type_alias| AssocTyValue::TypeAlias(type_alias).to_chalk(db))
         .collect();
@@ -713,7 +714,7 @@ fn closure_fn_trait_impl_datum(
     // and don't want to return a valid value only to find out later that FnOnce
     // is broken
     let fn_once_trait = get_fn_trait(db, krate, super::FnTrait::FnOnce)?;
-    fn_once_trait.associated_type_by_name(db, &name::OUTPUT_TYPE)?;
+    let _output = db.trait_data(fn_once_trait).associated_type_by_name(&name::OUTPUT_TYPE)?;
 
     let num_args: u16 = match &db.body(data.def.into())[data.expr] {
         crate::expr::Expr::Lambda { args, .. } => args.len() as u16,
@@ -735,8 +736,8 @@ fn closure_fn_trait_impl_datum(
     let self_ty = Ty::apply_one(TypeCtor::Closure { def: data.def, expr: data.expr }, sig_ty);
 
     let trait_ref = TraitRef {
-        trait_,
-        substs: Substs::build_for_def(db, trait_.id).push(self_ty).push(arg_ty).build(),
+        trait_: trait_.into(),
+        substs: Substs::build_for_def(db, trait_).push(self_ty).push(arg_ty).build(),
     };
 
     let output_ty_id = AssocTyValue::ClosureFnTraitImplOutput(data.clone()).to_chalk(db);
@@ -783,10 +784,10 @@ fn type_alias_associated_ty_value(
         .target_trait_ref(db)
         .expect("assoc ty value should not exist") // we don't return any assoc ty values if the impl'd trait can't be resolved
         .trait_;
-    let assoc_ty = trait_
-        .associated_type_by_name(db, &type_alias.name(db))
-        .expect("assoc ty value should not exist") // validated when building the impl data as well
-        .id;
+    let assoc_ty = db
+        .trait_data(trait_.id)
+        .associated_type_by_name(&type_alias.name(db))
+        .expect("assoc ty value should not exist"); // validated when building the impl data as well
     let generic_params = db.generic_params(impl_block.id.into());
     let bound_vars = Substs::bound_vars(&generic_params);
     let ty = db.type_for_def(type_alias.into(), crate::ty::Namespace::Types).subst(&bound_vars);
@@ -819,10 +820,10 @@ fn closure_fn_trait_output_assoc_ty_value(
     let fn_once_trait =
         get_fn_trait(db, krate, super::FnTrait::FnOnce).expect("assoc ty value should not exist");
 
-    let output_ty_id = fn_once_trait
-        .associated_type_by_name(db, &name::OUTPUT_TYPE)
-        .expect("assoc ty value should not exist")
-        .id;
+    let output_ty_id = db
+        .trait_data(fn_once_trait)
+        .associated_type_by_name(&name::OUTPUT_TYPE)
+        .expect("assoc ty value should not exist");
 
     let value_bound = chalk_rust_ir::AssociatedTyValueBound { ty: output_ty.to_chalk(db) };
 
@@ -834,10 +835,10 @@ fn closure_fn_trait_output_assoc_ty_value(
     Arc::new(value)
 }
 
-fn get_fn_trait(db: &impl HirDatabase, krate: Crate, fn_trait: super::FnTrait) -> Option<Trait> {
+fn get_fn_trait(db: &impl HirDatabase, krate: Crate, fn_trait: super::FnTrait) -> Option<TraitId> {
     let target = db.lang_item(krate.crate_id, fn_trait.lang_item_name().into())?;
     match target {
-        LangItemTarget::TraitId(t) => Some(t.into()),
+        LangItemTarget::TraitId(t) => Some(t),
         _ => None,
     }
 }
diff --git a/crates/ra_hir/src/ty/utils.rs b/crates/ra_hir/src/ty/utils.rs
new file mode 100644
index 000000000..52994b9e3
--- /dev/null
+++ b/crates/ra_hir/src/ty/utils.rs
@@ -0,0 +1,63 @@
+//! Helper functions for working with def, which don't need to be a separate
+//! query, but can't be computed directly from `*Data` (ie, which need a `db`).
+
+use hir_def::{
+    db::DefDatabase,
+    resolver::{HasResolver, TypeNs},
+    type_ref::TypeRef,
+    TraitId, TypeAliasId,
+};
+use hir_expand::name::{self, Name};
+
+// FIXME: this is wrong, b/c it can't express `trait T: PartialEq<()>`.
+// We should return a `TraitREf` here.
+fn direct_super_traits(db: &impl DefDatabase, trait_: TraitId) -> Vec<TraitId> {
+    let resolver = trait_.resolver(db);
+    // returning the iterator directly doesn't easily work because of
+    // lifetime problems, but since there usually shouldn't be more than a
+    // few direct traits this should be fine (we could even use some kind of
+    // SmallVec if performance is a concern)
+    db.generic_params(trait_.into())
+        .where_predicates
+        .iter()
+        .filter_map(|pred| match &pred.type_ref {
+            TypeRef::Path(p) if p.as_ident() == Some(&name::SELF_TYPE) => pred.bound.as_path(),
+            _ => None,
+        })
+        .filter_map(|path| match resolver.resolve_path_in_type_ns_fully(db, path) {
+            Some(TypeNs::TraitId(t)) => Some(t),
+            _ => None,
+        })
+        .collect()
+}
+
+/// Returns an iterator over the whole super trait hierarchy (including the
+/// trait itself).
+pub(crate) fn all_super_traits(db: &impl DefDatabase, trait_: TraitId) -> Vec<TraitId> {
+    // we need to take care a bit here to avoid infinite loops in case of cycles
+    // (i.e. if we have `trait A: B; trait B: A;`)
+    let mut result = vec![trait_];
+    let mut i = 0;
+    while i < result.len() {
+        let t = result[i];
+        // yeah this is quadratic, but trait hierarchies should be flat
+        // enough that this doesn't matter
+        for tt in direct_super_traits(db, t) {
+            if !result.contains(&tt) {
+                result.push(tt);
+            }
+        }
+        i += 1;
+    }
+    result
+}
+
+pub(crate) fn associated_type_by_name_including_super_traits(
+    db: &impl DefDatabase,
+    trait_: TraitId,
+    name: &Name,
+) -> Option<TypeAliasId> {
+    all_super_traits(db, trait_)
+        .into_iter()
+        .find_map(|t| db.trait_data(t).associated_type_by_name(name))
+}