internal: intern `TypeBound`s

Doesn't save much memory (~2 mb), but interning things is generally a
good pattern to follow

2 files changed, 8 insertions, 7 deletions

diff --git a/crates/hir_def/src/item_tree/lower.rs b/crates/hir_def/src/item_tree/lower.rs
index 91cf75371..1a0e54413 100644
--- a/crates/hir_def/src/item_tree/lower.rs
+++ b/crates/hir_def/src/item_tree/lower.rs
@@ -384,7 +384,7 @@ impl<'a> Ctx<'a> {
 
         let ret_type = if func.async_token().is_some() {
             let future_impl = desugar_future_path(ret_type);
-            let ty_bound = TypeBound::Path(future_impl);
+            let ty_bound = Interned::new(TypeBound::Path(future_impl));
             TypeRef::ImplTrait(vec![ty_bound])
         } else {
             ret_type
@@ -738,11 +738,12 @@ impl<'a> Ctx<'a> {
         Interned::new(generics)
     }
 
-    fn lower_type_bounds(&mut self, node: &impl ast::TypeBoundsOwner) -> Vec<TypeBound> {
+    fn lower_type_bounds(&mut self, node: &impl ast::TypeBoundsOwner) -> Vec<Interned<TypeBound>> {
         match node.type_bound_list() {
-            Some(bound_list) => {
-                bound_list.bounds().map(|it| TypeBound::from_ast(&self.body_ctx, it)).collect()
-            }
+            Some(bound_list) => bound_list
+                .bounds()
+                .map(|it| Interned::new(TypeBound::from_ast(&self.body_ctx, it)))
+                .collect(),
             None => Vec::new(),
         }
     }
diff --git a/crates/hir_def/src/item_tree/pretty.rs b/crates/hir_def/src/item_tree/pretty.rs
index 4bc87a0e2..9394a5de6 100644
--- a/crates/hir_def/src/item_tree/pretty.rs
+++ b/crates/hir_def/src/item_tree/pretty.rs
@@ -513,13 +513,13 @@ impl<'a> Printer<'a> {
         }
     }
 
-    fn print_type_bounds(&mut self, bounds: &[TypeBound]) {
+    fn print_type_bounds(&mut self, bounds: &[Interned<TypeBound>]) {
         for (i, bound) in bounds.iter().enumerate() {
             if i != 0 {
                 w!(self, " + ");
             }
 
-            match bound {
+            match bound.as_ref() {
                 TypeBound::Path(path) => self.print_path(path),
                 TypeBound::Lifetime(lt) => w!(self, "{}", lt.name),
                 TypeBound::Error => w!(self, "{{unknown}}"),