From 24e876b52ed76710593895bc37bb8ed303075193 Mon Sep 17 00:00:00 2001
From: Jonas Schievink <jonasschievink@gmail.com>
Date: Mon, 5 Apr 2021 02:03:37 +0200
Subject: Intern more `TypeRef`s in generics

Saves ~3 MB
---
 crates/hir_def/src/generics.rs   | 16 +++++++++-------
 crates/hir_def/src/path.rs       |  2 +-
 crates/hir_def/src/path/lower.rs |  2 +-
 crates/hir_ty/src/utils.rs       |  9 ++++-----
 4 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/crates/hir_def/src/generics.rs b/crates/hir_def/src/generics.rs
index 7c6cbff11..e02ac2c2f 100644
--- a/crates/hir_def/src/generics.rs
+++ b/crates/hir_def/src/generics.rs
@@ -18,6 +18,7 @@ use crate::{
     child_by_source::ChildBySource,
     db::DefDatabase,
     dyn_map::DynMap,
+    intern::Interned,
     keys,
     src::{HasChildSource, HasSource},
     type_ref::{LifetimeRef, TypeBound, TypeRef},
@@ -29,7 +30,7 @@ use crate::{
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub struct TypeParamData {
     pub name: Option<Name>,
-    pub default: Option<TypeRef>,
+    pub default: Option<Interned<TypeRef>>,
     pub provenance: TypeParamProvenance,
 }
 
@@ -43,7 +44,7 @@ pub struct LifetimeParamData {
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub struct ConstParamData {
     pub name: Name,
-    pub ty: TypeRef,
+    pub ty: Interned<TypeRef>,
 }
 
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
@@ -75,7 +76,7 @@ pub enum WherePredicate {
 
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub enum WherePredicateTypeTarget {
-    TypeRef(TypeRef),
+    TypeRef(Interned<TypeRef>),
     /// For desugared where predicates that can directly refer to a type param.
     TypeParam(LocalTypeParamId),
 }
@@ -256,7 +257,8 @@ impl GenericParams {
         for type_param in params.type_params() {
             let name = type_param.name().map_or_else(Name::missing, |it| it.as_name());
             // FIXME: Use `Path::from_src`
-            let default = type_param.default_type().map(|it| TypeRef::from_ast(lower_ctx, it));
+            let default =
+                type_param.default_type().map(|it| Interned::new(TypeRef::from_ast(lower_ctx, it)));
             let param = TypeParamData {
                 name: Some(name.clone()),
                 default,
@@ -280,7 +282,7 @@ impl GenericParams {
         for const_param in params.const_params() {
             let name = const_param.name().map_or_else(Name::missing, |it| it.as_name());
             let ty = const_param.ty().map_or(TypeRef::Error, |it| TypeRef::from_ast(lower_ctx, it));
-            let param = ConstParamData { name, ty };
+            let param = ConstParamData { name, ty: Interned::new(ty) };
             let param_id = self.consts.alloc(param);
             sm.const_params.insert(param_id, const_param.clone());
         }
@@ -334,11 +336,11 @@ impl GenericParams {
             (Either::Left(type_ref), bound) => match hrtb_lifetimes {
                 Some(hrtb_lifetimes) => WherePredicate::ForLifetime {
                     lifetimes: hrtb_lifetimes.clone(),
-                    target: WherePredicateTypeTarget::TypeRef(type_ref),
+                    target: WherePredicateTypeTarget::TypeRef(Interned::new(type_ref)),
                     bound,
                 },
                 None => WherePredicate::TypeBound {
-                    target: WherePredicateTypeTarget::TypeRef(type_ref),
+                    target: WherePredicateTypeTarget::TypeRef(Interned::new(type_ref)),
                     bound,
                 },
             },
diff --git a/crates/hir_def/src/path.rs b/crates/hir_def/src/path.rs
index a3e83e2cf..f9c8328f0 100644
--- a/crates/hir_def/src/path.rs
+++ b/crates/hir_def/src/path.rs
@@ -122,7 +122,7 @@ impl ModPath {
 pub struct Path {
     /// Type based path like `<T>::foo`.
     /// Note that paths like `<Type as Trait>::foo` are desugard to `Trait::<Self=Type>::foo`.
-    type_anchor: Option<Box<TypeRef>>,
+    type_anchor: Option<Interned<TypeRef>>,
     mod_path: Interned<ModPath>,
     /// Invariant: the same len as `self.mod_path.segments`
     generic_args: Vec<Option<Arc<GenericArgs>>>,
diff --git a/crates/hir_def/src/path/lower.rs b/crates/hir_def/src/path/lower.rs
index 28f6244da..7b29d9d4f 100644
--- a/crates/hir_def/src/path/lower.rs
+++ b/crates/hir_def/src/path/lower.rs
@@ -69,7 +69,7 @@ pub(super) fn lower_path(mut path: ast::Path, hygiene: &Hygiene) -> Option<Path>
                 match trait_ref {
                     // <T>::foo
                     None => {
-                        type_anchor = Some(Box::new(self_type));
+                        type_anchor = Some(Interned::new(self_type));
                         kind = PathKind::Plain;
                     }
                     // <T as Trait<A>>::Foo desugars to Trait<Self=T, A>::Foo
diff --git a/crates/hir_ty/src/utils.rs b/crates/hir_ty/src/utils.rs
index b23e91b1b..c85c328af 100644
--- a/crates/hir_ty/src/utils.rs
+++ b/crates/hir_ty/src/utils.rs
@@ -32,11 +32,10 @@ fn direct_super_traits(db: &dyn DefDatabase, trait_: TraitId) -> Vec<TraitId> {
         .filter_map(|pred| match pred {
             WherePredicate::ForLifetime { target, bound, .. }
             | WherePredicate::TypeBound { target, bound } => match target {
-                WherePredicateTypeTarget::TypeRef(TypeRef::Path(p))
-                    if p == &Path::from(name![Self]) =>
-                {
-                    bound.as_path()
-                }
+                WherePredicateTypeTarget::TypeRef(type_ref) => match &**type_ref {
+                    TypeRef::Path(p) if p == &Path::from(name![Self]) => bound.as_path(),
+                    _ => None,
+                },
                 WherePredicateTypeTarget::TypeParam(local_id) if Some(*local_id) == trait_self => {
                     bound.as_path()
                 }
-- 
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