Unify walk_capture_by

Author: maxcabrajac

compiler/rustc_ast/src/visitors.rs

@@ -297,12 +297,14 @@ macro_rules! make_ast_visitor {
             make_visit!{MutTy, visit_mt, walk_mt}
             make_visit!{WhereClause, visit_where_clause, walk_where_clause}
             make_visit!{EnumDef, visit_enum_def, walk_enum_def}
+            make_visit!{CaptureBy, visit_capture_by, walk_capture_by}
             make_visit!{P!(Local), visit_local, walk_local}
             make_visit!{P!(Pat), visit_pat, walk_pat}
             make_visit!{P!(Expr), visit_expr, walk_expr}
             make_visit!{P!(Ty), visit_ty, walk_ty}
             make_visit!{P!(Block), visit_block, walk_block}
             make_visit!{P!(FnDecl), visit_fn_decl, walk_fn_decl}
+
             // flat_maps
             make_visit!{Arm, visit_arm, walk_arm, flat_map_arm, walk_flat_map_arm}
             make_visit!{ExprField, visit_expr_field, walk_expr_field, flat_map_expr_field, walk_flat_map_expr_field}
@@ -344,15 +346,6 @@ macro_rules! make_ast_visitor {
                 walk_ident(self, ident)
             }
 
-            // FIXME: remove _ on capture_by if mut
-            fn visit_capture_by(&mut self, _capture_by: ref_t!(CaptureBy)) -> result!() {
-                if_mut_expr!(
-                    walk_capture_by(self, _capture_by)
-                ,
-                    Self::Result::output()
-                )
-            }
-
             // FIXME: remove _ on header if mut
             fn visit_fn_header(&mut self, _header: ref_t!(FnHeader)) -> result!() {
                 if_mut_expr!(
@@ -590,6 +583,19 @@ macro_rules! make_ast_visitor {
             return_result!(V)
         }
 
+        pub fn walk_capture_by<$($lt,)? V: $trait$(<$lt>)?>(
+            vis: &mut V,
+            capture_by: ref_t!(CaptureBy)
+        ) -> result!(V) {
+            match capture_by {
+                CaptureBy::Ref => {}
+                CaptureBy::Value { move_kw } => {
+                    try_v!(visit_span!(vis, move_kw))
+                }
+            }
+            return_result!(V)
+        }
+
         make_walk_flat_map!{Arm, walk_flat_map_arm, visit_arm}
         make_walk_flat_map!{ExprField, walk_flat_map_expr_field, visit_expr_field}
         make_walk_flat_map!{FieldDef, walk_flat_map_field_def, visit_field_def}
@@ -2939,15 +2945,6 @@ pub mod mut_visit {
         vis.visit_span(span);
     }
 
-    fn walk_capture_by<T: MutVisitor>(vis: &mut T, capture_by: &mut CaptureBy) {
-        match capture_by {
-            CaptureBy::Ref => {}
-            CaptureBy::Value { move_kw } => {
-                vis.visit_span(move_kw);
-            }
-        }
-    }
-
     pub fn walk_enum_def<T: MutVisitor>(vis: &mut T, EnumDef { variants }: &mut EnumDef) {
         variants.flat_map_in_place(|variant| vis.flat_map_variant(variant));
     }