Shrink ast::Impl.

Author: nnethercote

compiler/rustc_ast/src/ast.rs

@@ -2801,7 +2801,7 @@ pub struct Impl {
     /// The trait being implemented, if any.
     pub of_trait: Option<TraitRef>,
     pub self_ty: P<Ty>,
-    pub items: Vec<P<AssocItem>>,
+    pub items: Box<[P<AssocItem>]>,
 }
 
 #[derive(Clone, Encodable, Decodable, Debug)]
@@ -3048,7 +3048,7 @@ mod size_asserts {
     static_assert_size!(GenericArg, 24);
     static_assert_size!(GenericBound, 88);
     static_assert_size!(Generics, 72);
-    static_assert_size!(Impl, 200);
+    static_assert_size!(Impl, 192);
     static_assert_size!(Item, 184);
     static_assert_size!(ItemKind, 112);
     static_assert_size!(Lit, 48);

compiler/rustc_ast/src/visit.rs

@@ -340,7 +340,7 @@ pub fn walk_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a Item) {
             visitor.visit_generics(generics);
             walk_list!(visitor, visit_trait_ref, of_trait);
             visitor.visit_ty(self_ty);
-            walk_list!(visitor, visit_assoc_item, items, AssocCtxt::Impl);
+            walk_list!(visitor, visit_assoc_item, items.iter(), AssocCtxt::Impl);
         }
         ItemKind::Struct(ref struct_definition, ref generics)
         | ItemKind::Union(ref struct_definition, ref generics) => {

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -1052,7 +1052,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                     this.visit_trait_ref(t);
                     this.visit_ty(self_ty);
 
-                    walk_list!(this, visit_assoc_item, items, AssocCtxt::Impl);
+                    walk_list!(this, visit_assoc_item, items.iter(), AssocCtxt::Impl);
                 });
                 return; // Avoid visiting again.
             }

compiler/rustc_ast_pretty/src/pprust/state/item.rs

@@ -294,7 +294,7 @@ impl<'a> State<'a> {
                 self.space();
                 self.bopen();
                 self.print_inner_attributes(&item.attrs);
-                for impl_item in items {
+                for impl_item in items.iter() {
                     self.print_assoc_item(impl_item);
                 }
                 let empty = item.attrs.is_empty() && items.is_empty();

compiler/rustc_builtin_macros/src/deriving/mod.rs

@@ -187,7 +187,7 @@ fn inject_impl_of_structural_trait(
             generics,
             of_trait: Some(trait_ref),
             self_ty: self_type,
-            items: Vec::new(),
+            items: Box::new([]),
         })),
     );
 

compiler/rustc_parse/src/parser/item.rs

@@ -637,7 +637,7 @@ impl<'a> Parser<'a> {
                     generics,
                     of_trait: Some(trait_ref),
                     self_ty: ty_second,
-                    items: impl_items,
+                    items: impl_items.into_boxed_slice(),
                 }))
             }
             None => {
@@ -650,7 +650,7 @@ impl<'a> Parser<'a> {
                     generics,
                     of_trait: None,
                     self_ty: ty_first,
-                    items: impl_items,
+                    items: impl_items.into_boxed_slice(),
                 }))
             }
         };