7 files changed, 76 insertions, 75 deletions

diff --git a/crates/ra_hir_ty/src/db.rs b/crates/ra_hir_ty/src/db.rs
index aa2659c4b..9ce154593 100644
--- a/crates/ra_hir_ty/src/db.rs
+++ b/crates/ra_hir_ty/src/db.rs
@@ -11,7 +11,7 @@ use ra_db::{salsa, CrateId};
 use crate::{
     method_resolution::CrateImplBlocks,
     traits::{AssocTyValue, Impl},
-    CallableDef, FnSig, GenericPredicate, InferenceResult, Substs, Ty, TyDefId, TypeCtor,
+    CallableDef, FnSig, GenericPredicate, ImplTy, InferenceResult, Substs, Ty, TyDefId, TypeCtor,
     ValueTyDefId,
 };
 
@@ -27,6 +27,9 @@ pub trait HirDatabase: DefDatabase {
     #[salsa::invoke(crate::lower::value_ty_query)]
     fn value_ty(&self, def: ValueTyDefId) -> Ty;
 
+    #[salsa::invoke(crate::lower::impl_ty_query)]
+    fn impl_ty(&self, def: ImplId) -> ImplTy;
+
     #[salsa::invoke(crate::lower::field_types_query)]
     fn field_types(&self, var: VariantId) -> Arc<ArenaMap<LocalStructFieldId, Ty>>;
 
diff --git a/crates/ra_hir_ty/src/infer/coerce.rs b/crates/ra_hir_ty/src/infer/coerce.rs
index d66a21932..719a0f395 100644
--- a/crates/ra_hir_ty/src/infer/coerce.rs
+++ b/crates/ra_hir_ty/src/infer/coerce.rs
@@ -4,16 +4,11 @@
 //!
 //! See: https://doc.rust-lang.org/nomicon/coercions.html
 
-use hir_def::{
-    lang_item::LangItemTarget,
-    resolver::{HasResolver, Resolver},
-    type_ref::Mutability,
-    AdtId,
-};
+use hir_def::{lang_item::LangItemTarget, resolver::Resolver, type_ref::Mutability, AdtId};
 use rustc_hash::FxHashMap;
 use test_utils::tested_by;
 
-use crate::{autoderef, db::HirDatabase, Substs, TraitRef, Ty, TypeCtor, TypeWalk};
+use crate::{autoderef, db::HirDatabase, ImplTy, Substs, Ty, TypeCtor, TypeWalk};
 
 use super::{InEnvironment, InferTy, InferenceContext, TypeVarValue};
 
@@ -59,17 +54,12 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
         impls
             .iter()
             .filter_map(|&impl_id| {
-                let impl_data = db.impl_data(impl_id);
-                let resolver = impl_id.resolver(db);
-                let target_ty = Ty::from_hir(db, &resolver, &impl_data.target_type);
+                let trait_ref = match db.impl_ty(impl_id) {
+                    ImplTy::TraitRef(it) => it,
+                    ImplTy::Inherent(_) => return None,
+                };
 
                 // `CoerseUnsized` has one generic parameter for the target type.
-                let trait_ref = TraitRef::from_hir(
-                    db,
-                    &resolver,
-                    impl_data.target_trait.as_ref()?,
-                    Some(target_ty),
-                )?;
                 let cur_from_ty = trait_ref.substs.0.get(0)?;
                 let cur_to_ty = trait_ref.substs.0.get(1)?;
 
diff --git a/crates/ra_hir_ty/src/infer/path.rs b/crates/ra_hir_ty/src/infer/path.rs
index e6676e1aa..14be66836 100644
--- a/crates/ra_hir_ty/src/infer/path.rs
+++ b/crates/ra_hir_ty/src/infer/path.rs
@@ -2,7 +2,7 @@
 
 use hir_def::{
     path::{Path, PathKind, PathSegment},
-    resolver::{HasResolver, ResolveValueResult, Resolver, TypeNs, ValueNs},
+    resolver::{ResolveValueResult, Resolver, TypeNs, ValueNs},
     AssocItemId, ContainerId, Lookup,
 };
 use hir_expand::name::Name;
@@ -244,17 +244,15 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                 ContainerId::ImplId(it) => it,
                 _ => return None,
             };
-            let resolver = impl_id.resolver(self.db);
-            let impl_data = self.db.impl_data(impl_id);
-            let impl_block = Ty::from_hir(self.db, &resolver, &impl_data.target_type);
-            let impl_block_substs = impl_block.substs()?;
+            let self_ty = self.db.impl_ty(impl_id).self_type().clone();
+            let self_ty_substs = self_ty.substs()?;
             let actual_substs = actual_def_ty.substs()?;
 
             let mut new_substs = vec![Ty::Unknown; gen.count_parent_params()];
 
             // The following code *link up* the function actual parma type
             // and impl_block type param index
-            impl_block_substs.iter().zip(actual_substs.iter()).for_each(|(param, pty)| {
+            self_ty_substs.iter().zip(actual_substs.iter()).for_each(|(param, pty)| {
                 if let Ty::Param { idx, .. } = param {
                     if let Some(s) = new_substs.get_mut(*idx as usize) {
                         *s = pty.clone();
diff --git a/crates/ra_hir_ty/src/lib.rs b/crates/ra_hir_ty/src/lib.rs
index f25846326..c9ee34008 100644
--- a/crates/ra_hir_ty/src/lib.rs
+++ b/crates/ra_hir_ty/src/lib.rs
@@ -486,6 +486,21 @@ impl TypeWalk for TraitRef {
     }
 }
 
+#[derive(Clone, PartialEq, Eq, Debug)]
+pub enum ImplTy {
+    Inherent(Ty),
+    TraitRef(TraitRef),
+}
+
+impl ImplTy {
+    pub(crate) fn self_type(&self) -> &Ty {
+        match self {
+            ImplTy::Inherent(it) => it,
+            ImplTy::TraitRef(tr) => &tr.substs[0],
+        }
+    }
+}
+
 /// Like `generics::WherePredicate`, but with resolved types: A condition on the
 /// parameters of a generic item.
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
diff --git a/crates/ra_hir_ty/src/lower.rs b/crates/ra_hir_ty/src/lower.rs
index 53d955a12..f8331d257 100644
--- a/crates/ra_hir_ty/src/lower.rs
+++ b/crates/ra_hir_ty/src/lower.rs
@@ -14,21 +14,21 @@ use hir_def::{
     path::{GenericArg, Path, PathKind, PathSegment},
     resolver::{HasResolver, Resolver, TypeNs},
     type_ref::{TypeBound, TypeRef},
-    AdtId, AstItemDef, ConstId, EnumId, EnumVariantId, FunctionId, GenericDefId, HasModule,
+    AdtId, AstItemDef, ConstId, EnumId, EnumVariantId, FunctionId, GenericDefId, HasModule, ImplId,
     LocalStructFieldId, Lookup, StaticId, StructId, TraitId, TypeAliasId, UnionId, VariantId,
 };
 use ra_arena::map::ArenaMap;
 use ra_db::CrateId;
 
-use super::{
-    FnSig, GenericPredicate, ProjectionPredicate, ProjectionTy, Substs, TraitEnvironment, TraitRef,
-    Ty, TypeCtor, TypeWalk,
-};
 use crate::{
     db::HirDatabase,
     primitive::{FloatTy, IntTy},
-    utils::make_mut_slice,
-    utils::{all_super_traits, associated_type_by_name_including_super_traits, variant_data},
+    utils::{
+        all_super_traits, associated_type_by_name_including_super_traits, make_mut_slice,
+        variant_data,
+    },
+    FnSig, GenericPredicate, ImplTy, ProjectionPredicate, ProjectionTy, Substs, TraitEnvironment,
+    TraitRef, Ty, TypeCtor, TypeWalk,
 };
 
 impl Ty {
@@ -179,11 +179,7 @@ impl Ty {
                 let name = resolved_segment.name.clone();
                 Ty::Param { idx, name }
             }
-            TypeNs::SelfType(impl_id) => {
-                let impl_data = db.impl_data(impl_id);
-                let resolver = impl_id.resolver(db);
-                Ty::from_hir(db, &resolver, &impl_data.target_type)
-            }
+            TypeNs::SelfType(impl_id) => db.impl_ty(impl_id).self_type().clone(),
             TypeNs::AdtSelfType(adt) => db.ty(adt.into()),
 
             TypeNs::AdtId(it) => Ty::from_hir_path_inner(db, resolver, resolved_segment, it.into()),
@@ -751,3 +747,18 @@ pub(crate) fn value_ty_query(db: &impl HirDatabase, def: ValueTyDefId) -> Ty {
         ValueTyDefId::StaticId(it) => type_for_static(db, it),
     }
 }
+
+pub(crate) fn impl_ty_query(db: &impl HirDatabase, impl_id: ImplId) -> ImplTy {
+    let impl_data = db.impl_data(impl_id);
+    let resolver = impl_id.resolver(db);
+    let self_ty = Ty::from_hir(db, &resolver, &impl_data.target_type);
+    match impl_data.target_trait.as_ref() {
+        Some(trait_ref) => {
+            match TraitRef::from_hir(db, &resolver, trait_ref, Some(self_ty.clone())) {
+                Some(it) => ImplTy::TraitRef(it),
+                None => ImplTy::Inherent(self_ty),
+            }
+        }
+        None => ImplTy::Inherent(self_ty),
+    }
+}
diff --git a/crates/ra_hir_ty/src/method_resolution.rs b/crates/ra_hir_ty/src/method_resolution.rs
index 53c541eb8..ee1936b0e 100644
--- a/crates/ra_hir_ty/src/method_resolution.rs
+++ b/crates/ra_hir_ty/src/method_resolution.rs
@@ -6,8 +6,8 @@ use std::sync::Arc;
 
 use arrayvec::ArrayVec;
 use hir_def::{
-    lang_item::LangItemTarget, resolver::HasResolver, resolver::Resolver, type_ref::Mutability,
-    AssocItemId, AstItemDef, FunctionId, HasModule, ImplId, TraitId,
+    lang_item::LangItemTarget, resolver::Resolver, type_ref::Mutability, AssocItemId, AstItemDef,
+    FunctionId, HasModule, ImplId, TraitId,
 };
 use hir_expand::name::Name;
 use ra_db::CrateId;
@@ -15,14 +15,13 @@ use ra_prof::profile;
 use rustc_hash::FxHashMap;
 
 use crate::{
+    autoderef,
     db::HirDatabase,
     primitive::{FloatBitness, Uncertain},
     utils::all_super_traits,
-    Ty, TypeCtor,
+    Canonical, ImplTy, InEnvironment, TraitEnvironment, TraitRef, Ty, TypeCtor,
 };
 
-use super::{autoderef, Canonical, InEnvironment, TraitEnvironment, TraitRef};
-
 /// This is used as a key for indexing impls.
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub enum TyFingerprint {
@@ -59,22 +58,13 @@ impl CrateImplBlocks {
         let crate_def_map = db.crate_def_map(krate);
         for (_module_id, module_data) in crate_def_map.modules.iter() {
             for &impl_id in module_data.impls.iter() {
-                let impl_data = db.impl_data(impl_id);
-                let resolver = impl_id.resolver(db);
-
-                let target_ty = Ty::from_hir(db, &resolver, &impl_data.target_type);
-
-                match &impl_data.target_trait {
-                    Some(trait_ref) => {
-                        if let Some(tr) =
-                            TraitRef::from_hir(db, &resolver, &trait_ref, Some(target_ty))
-                        {
-                            res.impls_by_trait.entry(tr.trait_).or_default().push(impl_id);
-                        }
+                match db.impl_ty(impl_id) {
+                    ImplTy::TraitRef(tr) => {
+                        res.impls_by_trait.entry(tr.trait_).or_default().push(impl_id);
                     }
-                    None => {
-                        if let Some(target_ty_fp) = TyFingerprint::for_impl(&target_ty) {
-                            res.impls.entry(target_ty_fp).or_default().push(impl_id);
+                    ImplTy::Inherent(self_ty) => {
+                        if let Some(self_ty_fp) = TyFingerprint::for_impl(&self_ty) {
+                            res.impls.entry(self_ty_fp).or_default().push(impl_id);
                         }
                     }
                 }
diff --git a/crates/ra_hir_ty/src/traits/chalk.rs b/crates/ra_hir_ty/src/traits/chalk.rs
index 810e8c21a..35de37e6b 100644
--- a/crates/ra_hir_ty/src/traits/chalk.rs
+++ b/crates/ra_hir_ty/src/traits/chalk.rs
@@ -11,8 +11,8 @@ use chalk_rust_ir::{AssociatedTyDatum, AssociatedTyValue, ImplDatum, StructDatum
 use ra_db::CrateId;
 
 use hir_def::{
-    expr::Expr, lang_item::LangItemTarget, resolver::HasResolver, AssocItemId, AstItemDef,
-    ContainerId, GenericDefId, ImplId, Lookup, TraitId, TypeAliasId,
+    expr::Expr, lang_item::LangItemTarget, AssocItemId, AstItemDef, ContainerId, GenericDefId,
+    ImplId, Lookup, TraitId, TypeAliasId,
 };
 use hir_expand::name;
 
@@ -20,9 +20,8 @@ use ra_db::salsa::{InternId, InternKey};
 
 use super::{AssocTyValue, Canonical, ChalkContext, Impl, Obligation};
 use crate::{
-    db::HirDatabase,
-    display::HirDisplay,
-    {ApplicationTy, GenericPredicate, ProjectionTy, Substs, TraitRef, Ty, TypeCtor, TypeWalk},
+    db::HirDatabase, display::HirDisplay, ApplicationTy, GenericPredicate, ImplTy, ProjectionTy,
+    Substs, TraitRef, Ty, TypeCtor, TypeWalk,
 };
 
 /// This represents a trait whose name we could not resolve.
@@ -631,13 +630,11 @@ fn impl_block_datum(
     chalk_id: chalk_ir::ImplId,
     impl_id: ImplId,
 ) -> Option<Arc<ImplDatum<ChalkIr>>> {
+    let trait_ref = match db.impl_ty(impl_id) {
+        ImplTy::TraitRef(it) => it,
+        ImplTy::Inherent(_) => return None,
+    };
     let impl_data = db.impl_data(impl_id);
-    let resolver = impl_id.resolver(db);
-    let target_ty = Ty::from_hir(db, &resolver, &impl_data.target_type);
-
-    // `CoerseUnsized` has one generic parameter for the target type.
-    let trait_ref =
-        TraitRef::from_hir(db, &resolver, impl_data.target_trait.as_ref()?, Some(target_ty))?;
 
     let generic_params = db.generic_params(impl_id.into());
     let bound_vars = Substs::bound_vars(&generic_params);
@@ -790,17 +787,14 @@ fn type_alias_associated_ty_value(
         _ => panic!("assoc ty value should be in impl"),
     };
 
-    let impl_data = db.impl_data(impl_id);
-    let resolver = impl_id.resolver(db);
-    let target_ty = Ty::from_hir(db, &resolver, &impl_data.target_type);
-    let target_trait = impl_data
-        .target_trait
-        .as_ref()
-        .and_then(|trait_ref| TraitRef::from_hir(db, &resolver, &trait_ref, Some(target_ty)))
-        .expect("assoc ty value should not exist"); // we don't return any assoc ty values if the impl'd trait can't be resolved
+    let trait_ref = match db.impl_ty(impl_id) {
+        ImplTy::TraitRef(it) => it,
+        // we don't return any assoc ty values if the impl'd trait can't be resolved
+        ImplTy::Inherent(_) => panic!("assoc ty value should not exist"),
+    };
 
     let assoc_ty = db
-        .trait_data(target_trait.trait_)
+        .trait_data(trait_ref.trait_)
         .associated_type_by_name(&type_alias_data.name)
         .expect("assoc ty value should not exist"); // validated when building the impl data as well
     let generic_params = db.generic_params(impl_id.into());