A visitor that builds a map from node to "Usage".

lib/compiler/implementation/tree/unparser.dart

Index: lib/compiler/implementation/tree/unparser.dart
diff --git a/lib/compiler/implementation/tree/unparser.dart b/lib/compiler/implementation/tree/unparser.dart
index 2140a2a2d807e859d6e0e3d87c710534e1402fe2..8fea4240a58db9f3feeb7a466241be87bf610e4b 100644
--- a/lib/compiler/implementation/tree/unparser.dart
+++ b/lib/compiler/implementation/tree/unparser.dart
@@ -27,7 +27,14 @@ class Unparser implements Visitor {
   }
 
   visit(Node node) {
-    if (node !== null) node.accept(this);
+    if (node === null) return;
+    String renamed = renamer.rename(node);
+    if (renamed !== null) {
+      sb.add(renamed);
+    } else {
+      // Fallback.
+      node.accept(this);
+    }
   }
 
   visitBlock(Block node) {
@@ -106,20 +113,12 @@ class Unparser implements Visitor {
     // names are modelled with Send and it emits operator[] as only
     // operator, without [] which are expected to be emitted with
     // arguments.
-    emitName(Identifier name) {
-      final newName = renamer.renameIdentifier(name);
-      if (newName === null) {
-        visit(name);
-      } else {
-        sb.add(newName);
-      }
-    }
     if (node.name is Send) {
       Send send = node.name;
       assert(send is !SendSet);
       if (!send.isOperator) {
         // Looks like a factory method.
-        emitName(send.receiver);
+        visit(send.receiver);
         sb.add('.');
       } else {
         visit(send.receiver);
@@ -127,7 +126,7 @@ class Unparser implements Visitor {
       }
       visit(send.selector);
     } else {
-      if (node.name !== null) emitName(node.name);
+      if (node.name !== null) visit(node.name);
     }
     visit(node.parameters);
     visit(node.initializers);
@@ -237,7 +236,10 @@ class Unparser implements Visitor {
     if (node.isPrefix) {
       visit(node.selector);
     }
-    if (node.receiver !== null) {
+    // TODO(smok): Remove ugly hack for library preferences.
+    // Check that renamer does not want to omit receiver at all,
+    // in that case we don't need spaces or dot.
+    if (node.receiver !== null && renamer.rename(node.receiver) != '') {
       visit(node.receiver);
       CascadeReceiver asCascadeReceiver = node.receiver.asCascadeReceiver();
       if (asCascadeReceiver !== null) {
@@ -262,14 +264,8 @@ class Unparser implements Visitor {
   }
 
   visitSend(Send node) {
-    String newMethodName = renamer.renameSendMethod(node);
-    if (newMethodName !== null) {
-      sb.add(newMethodName);
-      visit(node.argumentsNode);
-    } else {
-      unparseSendPart(node);
-      visit(node.argumentsNode);
-    }
+    unparseSendPart(node);
+    visit(node.argumentsNode);
   }
 
   /**
@@ -318,14 +314,8 @@ class Unparser implements Visitor {
   }
 
   visitTypeAnnotation(TypeAnnotation node) {
-    String newName = renamer.renameTypeName(node);
-    if (newName !== null) {
-      sb.add(newName);
-      visit(node.typeArguments);
-    } else {
-      // Fallback to default unparse without renaming.
-      node.visitChildren(this);
-    }
+    visit(node.typeName);
+    visit(node.typeArguments);
   }
 
   visitTypeVariable(TypeVariable node) {