Add *IndexSetIfNull methods to SemanticSendVisitor.

pkg/compiler/lib/src/info/send_info.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /// Computes measurements about sends in a function.
 library compiler.src.info.send_info;
 
 import 'package:dart2js_info/src/measurements.dart';
 import 'package:dart2js_info/src/util.dart' show
     recursiveDiagnosticString;
@@ skipping 2207 matching lines @@
       SendSet node, ConstantExpression constant, Node rhs, T arg) {
     handleNSMError(node);
   }
 
   void visitDynamicTypeLiteralSetIfNull(
       SendSet node, ConstantExpression constant, Node rhs, T arg) {
     handleStatic(node);
     handleNSMError(node);
   }
 
+  @override
+  errorInvalidIndexSetIfNull(SendSet node, ErroneousElement error, Node index,
+      Node rhs, T arg) {
+    handleNoSend(node);
+  }
+
+  @override
+  visitIndexSetIfNull(SendSet node, Node receiver, Node index, Node rhs,
+      T arg) {
+    handleIndex(node); // t1 = receiver[index]
+    handleIndex(node); // receiver[index] = t2
+  }
+
+  @override
+  visitSuperIndexSetIfNull(SendSet node, MethodElement getter,
+      MethodElement setter, Node index, Node rhs, T arg) {
+    handleSuper(node); // t1 = super[index]
+    handleSuper(node); // super[index] = t2
+  }
+
+  @override
+  visitUnresolvedSuperGetterIndexSetIfNull(Send node, Element element,
+      MethodElement setter, Node index, Node rhs, T arg) {
+    handleNSMSuper(node, element.enclosingClass);
+    handleNSMSuper(node, element.enclosingClass);
+  }
+
+  @override
+  visitUnresolvedSuperIndexSetIfNull(Send node, Element element, Node index,
+      Node rhs, T arg) {
+    handleNSMSuper(node, element.enclosingClass);
+    handleNSMSuper(node, element.enclosingClass);
+  }
+
+  @override
+  visitUnresolvedSuperSetterIndexSetIfNull(Send node, MethodElement getter,
+      Element element, Node index, Node rhs, T arg) {
+    handleSuper(node); // t1 = super[index]
+    handleNSMSuper(node, element.enclosingClass);
+  }
+
   void visitIfNull(Send node, Node left, Node right, T arg) {
     handleNoSend(node);
   }
 
   void visitIs(Send node, Node expression, DartType type, T arg) {
     handleNoSend(node);
   }
 
   void visitIsNot(Send node, Node expression, DartType type, T arg) {
     handleNoSend(node);
@@ skipping 142 matching lines @@
   @override
   R visitClosureFieldElement(ClosureFieldElement e, A arg) {
     return visitVariableElement(e, arg);
   }
 }
 
 // TODO(sigmund): get rid of debug messages.
 _debug(String message) {
   print('debug: $message');
 }