From c1362d8cc53176e0bf0db73fefc98ca9b9035457 Mon Sep 17 00:00:00 2001
From: Jeffrey Seyfried <jeffrey.seyfried@gmail.com>
Date: Mon, 15 Aug 2016 01:08:31 +0000
Subject: [PATCH] Clean up `build_reduced_graph.rs`.

---
 src/librustc_resolve/build_reduced_graph.rs | 44 +++++++++------------
 1 file changed, 18 insertions(+), 26 deletions(-)

diff --git a/src/librustc_resolve/build_reduced_graph.rs b/src/librustc_resolve/build_reduced_graph.rs
index 2dac64ad2bba..3b3058c6da7b 100644
--- a/src/librustc_resolve/build_reduced_graph.rs
+++ b/src/librustc_resolve/build_reduced_graph.rs
@@ -56,12 +56,7 @@ impl<'b> Resolver<'b> {
     pub fn build_reduced_graph(&mut self, krate: &Crate) {
         let no_implicit_prelude = attr::contains_name(&krate.attrs, "no_implicit_prelude");
         self.graph_root.no_implicit_prelude.set(no_implicit_prelude);
-
-        let mut visitor = BuildReducedGraphVisitor {
-            parent: self.graph_root,
-            resolver: self,
-        };
-        visit::walk_crate(&mut visitor, krate);
+        visit::walk_crate(&mut BuildReducedGraphVisitor { resolver: self }, krate);
     }
 
     /// Defines `name` in namespace `ns` of module `parent` to be `def` if it is not yet defined;
@@ -84,11 +79,10 @@ impl<'b> Resolver<'b> {
     }
 
     /// Constructs the reduced graph for one item.
-    fn build_reduced_graph_for_item(&mut self, item: &Item, parent_ref: &mut Module<'b>) {
-        let parent = *parent_ref;
+    fn build_reduced_graph_for_item(&mut self, item: &Item) {
+        let parent = self.current_module;
         let name = item.ident.name;
         let sp = item.span;
-        self.current_module = parent;
         let vis = self.resolve_visibility(&item.vis);
 
         match item.node {
@@ -213,7 +207,7 @@ impl<'b> Resolver<'b> {
                 });
                 self.define(parent, name, TypeNS, (module, sp, vis));
                 self.module_map.insert(item.id, module);
-                *parent_ref = module;
+                self.current_module = module; // Descend into the module.
             }
 
             ItemKind::ForeignMod(..) => {}
@@ -306,6 +300,9 @@ impl<'b> Resolver<'b> {
             }
             ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
         }
+
+        visit::walk_item(&mut BuildReducedGraphVisitor { resolver: self }, item);
+        self.current_module = parent;
     }
 
     // Constructs the reduced graph for one variant. Variants exist in the
@@ -330,9 +327,8 @@ impl<'b> Resolver<'b> {
     }
 
     /// Constructs the reduced graph for one foreign item.
-    fn build_reduced_graph_for_foreign_item(&mut self,
-                                            foreign_item: &ForeignItem,
-                                            parent: Module<'b>) {
+    fn build_reduced_graph_for_foreign_item(&mut self, foreign_item: &ForeignItem) {
+        let parent = self.current_module;
         let name = foreign_item.ident.name;
 
         let def = match foreign_item.node {
@@ -343,12 +339,12 @@ impl<'b> Resolver<'b> {
                 Def::Static(self.definitions.local_def_id(foreign_item.id), m)
             }
         };
-        self.current_module = parent;
         let vis = self.resolve_visibility(&foreign_item.vis);
         self.define(parent, name, ValueNS, (def, foreign_item.span, vis));
     }
 
-    fn build_reduced_graph_for_block(&mut self, block: &Block, parent: &mut Module<'b>) {
+    fn build_reduced_graph_for_block(&mut self, block: &Block) {
+        let parent = self.current_module;
         if self.block_needs_anonymous_module(block) {
             let block_id = block.id;
 
@@ -359,8 +355,11 @@ impl<'b> Resolver<'b> {
             let parent_link = BlockParentLink(parent, block_id);
             let new_module = self.new_module(parent_link, None, false);
             self.module_map.insert(block_id, new_module);
-            *parent = new_module;
+            self.current_module = new_module; // Descend into the block.
         }
+
+        visit::walk_block(&mut BuildReducedGraphVisitor { resolver: self }, block);
+        self.current_module = parent;
     }
 
     /// Builds the reduced graph for a single item in an external crate.
@@ -484,25 +483,18 @@ impl<'b> Resolver<'b> {
 
 struct BuildReducedGraphVisitor<'a, 'b: 'a> {
     resolver: &'a mut Resolver<'b>,
-    parent: Module<'b>,
 }
 
 impl<'a, 'b> Visitor for BuildReducedGraphVisitor<'a, 'b> {
     fn visit_item(&mut self, item: &Item) {
-        let old_parent = self.parent;
-        self.resolver.build_reduced_graph_for_item(item, &mut self.parent);
-        visit::walk_item(self, item);
-        self.parent = old_parent;
+        self.resolver.build_reduced_graph_for_item(item);
     }
 
     fn visit_foreign_item(&mut self, foreign_item: &ForeignItem) {
-        self.resolver.build_reduced_graph_for_foreign_item(foreign_item, &self.parent);
+        self.resolver.build_reduced_graph_for_foreign_item(foreign_item);
     }
 
     fn visit_block(&mut self, block: &Block) {
-        let old_parent = self.parent;
-        self.resolver.build_reduced_graph_for_block(block, &mut self.parent);
-        visit::walk_block(self, block);
-        self.parent = old_parent;
+        self.resolver.build_reduced_graph_for_block(block);
     }
 }