diff --git a/pkg/compiler/lib/src/js_backend/codegen/codegen.dart b/pkg/compiler/lib/src/js_backend/codegen/codegen.dart
index aabb7a3f1b3..b852418c70e 100644
--- a/pkg/compiler/lib/src/js_backend/codegen/codegen.dart
+++ b/pkg/compiler/lib/src/js_backend/codegen/codegen.dart
@@ -156,8 +156,11 @@ class CodeGenerator extends tree_ir.StatementVisitor
     return name;
   }
 
-  List<js.Expression> visitArguments(List<tree_ir.Expression> arguments) {
-    return arguments.map(visitExpression).toList();
+  List<js.Expression> visitExpressionList(
+      List<tree_ir.Expression> expressions) {
+    return new List<js.Expression>.generate(expressions.length,
+        (int index) => visitExpression(expressions[index]),
+        growable: false);
   }
 
   giveup(tree_ir.Node node,
@@ -242,7 +245,7 @@ class CodeGenerator extends tree_ir.StatementVisitor
     registry.registerInstantiatedType(node.type);
     Selector selector = node.selector;
     FunctionElement target = node.target;
-    List<js.Expression> arguments = visitArguments(node.arguments);
+    List<js.Expression> arguments = visitExpressionList(node.arguments);
     return buildStaticInvoke(selector, target, arguments);
   }
 
@@ -269,7 +272,7 @@ class CodeGenerator extends tree_ir.StatementVisitor
     registerMethodInvoke(node);
     return js.propertyCall(visitExpression(node.receiver),
                            glue.invocationName(node.selector),
-                           visitArguments(node.arguments));
+                           visitExpressionList(node.arguments));
   }
 
   @override
@@ -277,7 +280,7 @@ class CodeGenerator extends tree_ir.StatementVisitor
     Selector selector = node.selector;
     assert(selector.isGetter || selector.isSetter || selector.isCall);
     FunctionElement target = node.target;
-    List<js.Expression> arguments = visitArguments(node.arguments);
+    List<js.Expression> arguments = visitExpressionList(node.arguments);
     return buildStaticInvoke(selector, target, arguments,
         sourceInformation: node.sourceInformation);
   }
@@ -291,19 +294,19 @@ class CodeGenerator extends tree_ir.StatementVisitor
       return js.js('#.#(#)',
           [visitExpression(node.receiver),
            glue.instanceMethodName(node.target),
-           visitArguments(node.arguments)]);
+           visitExpressionList(node.arguments)]);
     }
     return js.js('#.#.call(#, #)',
         [glue.prototypeAccess(node.target.enclosingClass),
          glue.invocationName(node.selector),
          visitExpression(node.receiver),
-         visitArguments(node.arguments)]);
+         visitExpressionList(node.arguments)]);
   }
 
   @override
   js.Expression visitLiteralList(tree_ir.LiteralList node) {
     registry.registerInstantiatedClass(glue.listClass);
-    List<js.Expression> entries = node.values.map(visitExpression).toList();
+    List<js.Expression> entries = visitExpressionList(node.values);
     return new js.ArrayInitializer(entries);
   }
 
@@ -351,8 +354,7 @@ class CodeGenerator extends tree_ir.StatementVisitor
   @override
   js.Expression visitTypeOperator(tree_ir.TypeOperator node) {
     js.Expression value = visitExpression(node.value);
-    List<js.Expression> typeArguments =
-        node.typeArguments.map(visitExpression).toList();
+    List<js.Expression> typeArguments = visitExpressionList(node.typeArguments);
     if (!node.isTypeTest) {
       giveup(node, 'type casts not implemented.');
     }
@@ -557,7 +559,7 @@ class CodeGenerator extends tree_ir.StatementVisitor
 
   @override
   js.Expression visitCreateBox(tree_ir.CreateBox node) {
-    return new js.ObjectInitializer([]);
+    return new js.ObjectInitializer(const <js.Property>[]);
   }
 
   @override
@@ -570,7 +572,7 @@ class CodeGenerator extends tree_ir.StatementVisitor
     registry.registerInstantiatedClass(cls);
     js.Expression instance = new js.New(
         glue.constructorAccess(cls),
-        node.arguments.map(visitExpression).toList());
+        visitExpressionList(node.arguments));
 
     List<tree_ir.Expression> typeInformation = node.typeInformation;
     assert(typeInformation.isEmpty ||
@@ -578,7 +580,7 @@ class CodeGenerator extends tree_ir.StatementVisitor
     if (typeInformation.isNotEmpty) {
       FunctionElement helper = glue.getAddRuntimeTypeInformation();
       js.Expression typeArguments = new js.ArrayInitializer(
-          typeInformation.map(visitExpression).toList());
+          visitExpressionList(typeInformation));
       return buildStaticHelperInvocation(helper,
           <js.Expression>[instance, typeArguments]);
     } else {
@@ -593,9 +595,9 @@ class CodeGenerator extends tree_ir.StatementVisitor
     js.Expression internalName = js.string(glue.invocationName(node.selector));
     js.Expression kind = js.number(node.selector.invocationMirrorKind);
     js.Expression arguments = new js.ArrayInitializer(
-        node.arguments.map(visitExpression).toList());
+        visitExpressionList(node.arguments));
     js.Expression argumentNames = new js.ArrayInitializer(
-        node.selector.namedArguments.map(js.string).toList());
+        node.selector.namedArguments.map(js.string).toList(growable: false));
     return buildStaticHelperInvocation(glue.createInvocationMirrorMethod,
         [name, internalName, kind, arguments, argumentNames]);
   }
@@ -628,7 +630,8 @@ class CodeGenerator extends tree_ir.StatementVisitor
       // Read a lazily initialized field.
       registry.registerStaticUse(node.element.declaration);
       js.Expression getter = glue.isolateLazyInitializerAccess(node.element);
-      return new js.Call(getter, [], sourceInformation: node.sourceInformation);
+      return new js.Call(getter, <js.Expression>[],
+          sourceInformation: node.sourceInformation);
     }
     // Read an eagerly initialized field.
     registry.registerStaticUse(node.element.declaration);
@@ -678,8 +681,7 @@ class CodeGenerator extends tree_ir.StatementVisitor
 
   @override
   js.Expression visitTypeExpression(tree_ir.TypeExpression node) {
-    List<js.Expression> arguments =
-        node.arguments.map(visitExpression).toList(growable: false);
+    List<js.Expression> arguments = visitExpressionList(node.arguments);
     return glue.generateTypeRepresentation(node.dartType, arguments);
   }