Use named fields for `ast::ItemKind::Impl`

4 files changed, 44 insertions, 25 deletions

diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 331eb109ec0..a5a4eb1583b 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -2614,15 +2614,18 @@ pub enum ItemKind {
     /// An implementation.
     ///
     /// E.g., `impl<A> Foo<A> { .. }` or `impl<A> Trait for Foo<A> { .. }`.
-    Impl(
-        Unsafety,
-        ImplPolarity,
-        Defaultness,
-        Generics,
-        Option<TraitRef>, // (optional) trait this impl implements
-        P<Ty>,            // self
-        Vec<AssocItem>,
-    ),
+    Impl {
+        unsafety: Unsafety,
+        polarity: ImplPolarity,
+        defaultness: Defaultness,
+        generics: Generics,
+
+        /// The trait being implemented, if any.
+        of_trait: Option<TraitRef>,
+
+        self_ty: P<Ty>,
+        items: Vec<AssocItem>,
+    },
     /// A macro invocation.
     ///
     /// E.g., `foo!(..)`.
@@ -2649,7 +2652,7 @@ impl ItemKind {
             ItemKind::Union(..) => "union",
             ItemKind::Trait(..) => "trait",
             ItemKind::TraitAlias(..) => "trait alias",
-            ItemKind::Mac(..) | ItemKind::MacroDef(..) | ItemKind::Impl(..) => "item",
+            ItemKind::Mac(..) | ItemKind::MacroDef(..) | ItemKind::Impl { .. } => "item",
         }
     }
 }
diff --git a/src/libsyntax/mut_visit.rs b/src/libsyntax/mut_visit.rs
index 58d4e46111b..750d054e8a0 100644
--- a/src/libsyntax/mut_visit.rs
+++ b/src/libsyntax/mut_visit.rs
@@ -918,10 +918,18 @@ pub fn noop_visit_item_kind<T: MutVisitor>(kind: &mut ItemKind, vis: &mut T) {
             vis.visit_variant_data(variant_data);
             vis.visit_generics(generics);
         }
-        ItemKind::Impl(_unsafety, _polarity, _defaultness, generics, trait_ref, ty, items) => {
+        ItemKind::Impl {
+            unsafety: _,
+            polarity: _,
+            defaultness: _,
+            generics,
+            of_trait,
+            self_ty,
+            items,
+        } => {
             vis.visit_generics(generics);
-            visit_opt(trait_ref, |trait_ref| vis.visit_trait_ref(trait_ref));
-            vis.visit_ty(ty);
+            visit_opt(of_trait, |trait_ref| vis.visit_trait_ref(trait_ref));
+            vis.visit_ty(self_ty);
             items.flat_map_in_place(|item| vis.flat_map_impl_item(item));
         }
         ItemKind::Trait(_is_auto, _unsafety, generics, bounds, items) => {
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index 11c8cb8ef75..bc67980c454 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -1226,15 +1226,15 @@ impl<'a> State<'a> {
                 self.head(visibility_qualified(&item.vis, "union"));
                 self.print_struct(struct_def, generics, item.ident, item.span, true);
             }
-            ast::ItemKind::Impl(
+            ast::ItemKind::Impl {
                 unsafety,
                 polarity,
                 defaultness,
                 ref generics,
-                ref opt_trait,
-                ref ty,
-                ref impl_items,
-            ) => {
+                ref of_trait,
+                ref self_ty,
+                ref items,
+            } => {
                 self.head("");
                 self.print_visibility(&item.vis);
                 self.print_defaultness(defaultness);
@@ -1250,19 +1250,19 @@ impl<'a> State<'a> {
                     self.s.word("!");
                 }
 
-                if let Some(ref t) = *opt_trait {
+                if let Some(ref t) = *of_trait {
                     self.print_trait_ref(t);
                     self.s.space();
                     self.word_space("for");
                 }
 
-                self.print_type(ty);
+                self.print_type(self_ty);
                 self.print_where_clause(&generics.where_clause);
 
                 self.s.space();
                 self.bopen();
                 self.print_inner_attributes(&item.attrs);
-                for impl_item in impl_items {
+                for impl_item in items {
                     self.print_assoc_item(impl_item);
                 }
                 self.bclose(item.span);
diff --git a/src/libsyntax/visit.rs b/src/libsyntax/visit.rs
index 3c2ebacbc4e..d03a9dfc167 100644
--- a/src/libsyntax/visit.rs
+++ b/src/libsyntax/visit.rs
@@ -308,11 +308,19 @@ pub fn walk_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a Item) {
             visitor.visit_generics(generics);
             visitor.visit_enum_def(enum_definition, generics, item.id, item.span)
         }
-        ItemKind::Impl(_, _, _, ref generics, ref opt_trait_reference, ref typ, ref impl_items) => {
+        ItemKind::Impl {
+            unsafety: _,
+            polarity: _,
+            defaultness: _,
+            ref generics,
+            ref of_trait,
+            ref self_ty,
+            ref items,
+        } => {
             visitor.visit_generics(generics);
-            walk_list!(visitor, visit_trait_ref, opt_trait_reference);
-            visitor.visit_ty(typ);
-            walk_list!(visitor, visit_impl_item, impl_items);
+            walk_list!(visitor, visit_trait_ref, of_trait);
+            visitor.visit_ty(self_ty);
+            walk_list!(visitor, visit_impl_item, items);
         }
         ItemKind::Struct(ref struct_definition, ref generics)
         | ItemKind::Union(ref struct_definition, ref generics) => {