1 files changed, 16 insertions, 23 deletions

diff --git a/crates/hir_ty/src/infer/path.rs b/crates/hir_ty/src/infer/path.rs
index cefa38509..495282eba 100644
--- a/crates/hir_ty/src/infer/path.rs
+++ b/crates/hir_ty/src/infer/path.rs
@@ -11,7 +11,8 @@ use hir_def::{
 use hir_expand::name::Name;
 
 use crate::{
-    method_resolution, to_chalk_trait_id, Interner, Substitution, Ty, TyKind, ValueTyDefId,
+    method_resolution, Interner, Substitution, TraitRefExt, Ty, TyBuilder, TyExt, TyKind,
+    ValueTyDefId,
 };
 
 use super::{ExprOrPatId, InferenceContext, TraitRef};
@@ -82,10 +83,10 @@ impl<'a> InferenceContext<'a> {
             }
             ValueNs::ImplSelf(impl_id) => {
                 let generics = crate::utils::generics(self.db.upcast(), impl_id.into());
-                let substs = Substitution::type_params_for_generics(self.db, &generics);
-                let ty = self.db.impl_self_ty(impl_id).subst(&substs);
+                let substs = generics.type_params_subst(self.db);
+                let ty = self.db.impl_self_ty(impl_id).substitute(&Interner, &substs);
                 if let Some((AdtId::StructId(struct_id), substs)) = ty.as_adt() {
-                    let ty = self.db.value_ty(struct_id.into()).subst(&substs);
+                    let ty = self.db.value_ty(struct_id.into()).substitute(&Interner, &substs);
                     return Some(ty);
                 } else {
                     // FIXME: diagnostic, invalid Self reference
@@ -95,16 +96,13 @@ impl<'a> InferenceContext<'a> {
             ValueNs::GenericParam(it) => return Some(self.db.const_param_ty(it)),
         };
 
-        let ty = self.db.value_ty(typable);
-        // self_subst is just for the parent
-        let parent_substs = self_subst.unwrap_or_else(Substitution::empty);
+        let parent_substs = self_subst.unwrap_or_else(|| Substitution::empty(&Interner));
         let ctx = crate::lower::TyLoweringContext::new(self.db, &self.resolver);
         let substs = ctx.substs_from_path(path, typable, true);
-        let full_substs = Substitution::builder(substs.len())
+        let ty = TyBuilder::value_ty(self.db, typable)
             .use_parent_substs(&parent_substs)
-            .fill(substs.0[parent_substs.len()..].iter().cloned())
+            .fill(substs.as_slice(&Interner)[parent_substs.len(&Interner)..].iter().cloned())
             .build();
-        let ty = ty.subst(&full_substs);
         Some(ty)
     }
 
@@ -147,7 +145,7 @@ impl<'a> InferenceContext<'a> {
                     remaining_segments_for_ty,
                     true,
                 );
-                if let TyKind::Unknown = ty.interned(&Interner) {
+                if let TyKind::Error = ty.kind(&Interner) {
                     return None;
                 }
 
@@ -212,7 +210,7 @@ impl<'a> InferenceContext<'a> {
         name: &Name,
         id: ExprOrPatId,
     ) -> Option<(ValueNs, Option<Substitution>)> {
-        if let TyKind::Unknown = ty.interned(&Interner) {
+        if let TyKind::Error = ty.kind(&Interner) {
             return None;
         }
 
@@ -245,27 +243,22 @@ impl<'a> InferenceContext<'a> {
                 };
                 let substs = match container {
                     AssocContainerId::ImplId(impl_id) => {
-                        let impl_substs = Substitution::build_for_def(self.db, impl_id)
+                        let impl_substs = TyBuilder::subst_for_def(self.db, impl_id)
                             .fill(iter::repeat_with(|| self.table.new_type_var()))
                             .build();
-                        let impl_self_ty = self.db.impl_self_ty(impl_id).subst(&impl_substs);
+                        let impl_self_ty =
+                            self.db.impl_self_ty(impl_id).substitute(&Interner, &impl_substs);
                         self.unify(&impl_self_ty, &ty);
                         Some(impl_substs)
                     }
                     AssocContainerId::TraitId(trait_) => {
                         // we're picking this method
-                        let trait_substs = Substitution::build_for_def(self.db, trait_)
+                        let trait_ref = TyBuilder::trait_ref(self.db, trait_)
                             .push(ty.clone())
                             .fill(std::iter::repeat_with(|| self.table.new_type_var()))
                             .build();
-                        self.obligations.push(
-                            TraitRef {
-                                trait_id: to_chalk_trait_id(trait_),
-                                substitution: trait_substs.clone(),
-                            }
-                            .cast(&Interner),
-                        );
-                        Some(trait_substs)
+                        self.push_obligation(trait_ref.clone().cast(&Interner));
+                        Some(trait_ref.substitution)
                     }
                     AssocContainerId::ModuleId(_) => None,
                 };