2 files changed, 17 insertions, 36 deletions

diff --git a/crates/hir_ty/src/infer/expr.rs b/crates/hir_ty/src/infer/expr.rs
index db8aeead2..5eb07126e 100644
--- a/crates/hir_ty/src/infer/expr.rs
+++ b/crates/hir_ty/src/infer/expr.rs
@@ -539,17 +539,10 @@ impl<'a> InferenceContext<'a> {
             Expr::Box { expr } => {
                 let inner_ty = self.infer_expr_inner(*expr, &Expectation::none());
                 if let Some(box_) = self.resolve_boxed_box() {
-                    let mut sb =
-                        Substitution::build_for_generics(&generics(self.db.upcast(), box_.into()));
-                    sb = sb.push(inner_ty);
-                    match self.db.generic_defaults(box_.into()).get(1) {
-                        Some(alloc_ty) if !alloc_ty.value.is_unknown() && sb.remaining() > 0 => {
-                            sb = sb.push(alloc_ty.value.clone());
-                        }
-                        _ => (),
-                    }
-                    sb = sb.fill(repeat_with(|| self.table.new_type_var()));
-                    Ty::adt_ty(box_, sb.build())
+                    TyBuilder::adt(self.db, box_)
+                        .push(inner_ty)
+                        .fill_with_defaults(self.db, || self.table.new_type_var())
+                        .build()
                 } else {
                     self.err_ty()
                 }
@@ -639,31 +632,31 @@ impl<'a> InferenceContext<'a> {
                 let rhs_ty = rhs.map(|e| self.infer_expr(e, &rhs_expect));
                 match (range_type, lhs_ty, rhs_ty) {
                     (RangeOp::Exclusive, None, None) => match self.resolve_range_full() {
-                        Some(adt) => Ty::adt_ty(adt, Substitution::empty(&Interner)),
+                        Some(adt) => TyBuilder::adt(self.db, adt).build(),
                         None => self.err_ty(),
                     },
                     (RangeOp::Exclusive, None, Some(ty)) => match self.resolve_range_to() {
-                        Some(adt) => Ty::adt_ty(adt, Substitution::single(ty)),
+                        Some(adt) => TyBuilder::adt(self.db, adt).push(ty).build(),
                         None => self.err_ty(),
                     },
                     (RangeOp::Inclusive, None, Some(ty)) => {
                         match self.resolve_range_to_inclusive() {
-                            Some(adt) => Ty::adt_ty(adt, Substitution::single(ty)),
+                            Some(adt) => TyBuilder::adt(self.db, adt).push(ty).build(),
                             None => self.err_ty(),
                         }
                     }
                     (RangeOp::Exclusive, Some(_), Some(ty)) => match self.resolve_range() {
-                        Some(adt) => Ty::adt_ty(adt, Substitution::single(ty)),
+                        Some(adt) => TyBuilder::adt(self.db, adt).push(ty).build(),
                         None => self.err_ty(),
                     },
                     (RangeOp::Inclusive, Some(_), Some(ty)) => {
                         match self.resolve_range_inclusive() {
-                            Some(adt) => Ty::adt_ty(adt, Substitution::single(ty)),
+                            Some(adt) => TyBuilder::adt(self.db, adt).push(ty).build(),
                             None => self.err_ty(),
                         }
                     }
                     (RangeOp::Exclusive, Some(ty), None) => match self.resolve_range_from() {
-                        Some(adt) => Ty::adt_ty(adt, Substitution::single(ty)),
+                        Some(adt) => TyBuilder::adt(self.db, adt).push(ty).build(),
                         None => self.err_ty(),
                     },
                     (RangeOp::Inclusive, _, None) => self.err_ty(),
diff --git a/crates/hir_ty/src/infer/pat.rs b/crates/hir_ty/src/infer/pat.rs
index 10df8d8cb..5b70d5e5a 100644
--- a/crates/hir_ty/src/infer/pat.rs
+++ b/crates/hir_ty/src/infer/pat.rs
@@ -13,9 +13,8 @@ use hir_expand::name::Name;
 
 use super::{BindingMode, Expectation, InferenceContext};
 use crate::{
-    lower::lower_to_chalk_mutability,
-    utils::{generics, variant_data},
-    Interner, Substitution, Ty, TyKind,
+    lower::lower_to_chalk_mutability, utils::variant_data, Interner, Substitution, Ty, TyBuilder,
+    TyKind,
 };
 
 impl<'a> InferenceContext<'a> {
@@ -246,23 +245,12 @@ impl<'a> InferenceContext<'a> {
                     };
 
                     let inner_ty = self.infer_pat(*inner, &inner_ty, default_bm);
-                    let mut sb = Substitution::build_for_generics(&generics(
-                        self.db.upcast(),
-                        box_adt.into(),
-                    ));
-                    sb = sb.push(inner_ty);
-                    if sb.remaining() == 1 {
-                        sb = sb.push(match alloc_ty {
-                            Some(alloc_ty) if !alloc_ty.is_unknown() => alloc_ty,
-                            _ => match self.db.generic_defaults(box_adt.into()).get(1) {
-                                Some(alloc_ty) if !alloc_ty.value.is_unknown() => {
-                                    alloc_ty.value.clone()
-                                }
-                                _ => self.table.new_type_var(),
-                            },
-                        });
+                    let mut b = TyBuilder::adt(self.db, box_adt).push(inner_ty);
+
+                    if let Some(alloc_ty) = alloc_ty {
+                        b = b.push(alloc_ty);
                     }
-                    Ty::adt_ty(box_adt, sb.build())
+                    b.fill_with_defaults(self.db, || self.table.new_type_var()).build()
                 }
                 None => self.err_ty(),
             },