Fix hints reported by analyzer.

pkg/compiler/lib/src/kernel/kernel_visitor.dart

 // Copyright (c) 2016, 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.md file.
 
 import 'package:kernel/ast.dart' as ir;
 import 'package:kernel/frontend/accessors.dart'
     show
         Accessor,
         IndexAccessor,
         NullAwarePropertyAccessor,
@@ skipping 1014 matching lines @@
     for (Link<Node> link = node.cases.nodes;
         link.isNotEmpty;
         link = link.tail) {
       SwitchCase caseNode = link.head;
       bool isLastCase = link.tail.isEmpty;
       if (!casesIterator.moveNext()) {
         internalError(caseNode, "case node mismatch");
       }
       ir.SwitchCase irCase = casesIterator.current;
       List<ir.Statement> statements = <ir.Statement>[];
-      bool hasVariableDeclaration = false;
       for (Statement statement in caseNode.statements.nodes) {
-        if (buildStatement(statement, statements)) {
-          hasVariableDeclaration = true;
-        }
+        buildStatement(statement, statements);
       }
       if (statements.isEmpty || fallsThrough(statements.last)) {
         if (isLastCase) {
           if (!caseNode.isDefaultCase) {
             statements.add(new ir.BreakStatement(
                 getBreakTarget(elements.getTargetDefinition(node))));
           }
         } else {
           statements.add(new ir.ExpressionStatement(new ir.Throw(
               new ir.ConstructorInvocation(
@@ skipping 1052 matching lines @@
           internalError(
               function, "Unknown async maker: ${function.asyncMarker}");
           break;
       }
     }
     ir.Statement body;
     if (function.isExternal) {
       // [body] must be `null`.
     } else if (function.isConstructor) {
       // TODO(johnniwinther): Clean this up pending kernel issue #28.
-      ConstructorElement constructor = function;
       if (bodyNode == null || bodyNode.asEmptyStatement() != null) {
         body = new ir.EmptyStatement();
       } else {
         body = buildStatementInBlock(bodyNode);
       }
     } else if (bodyNode != null) {
       Return returnStatement = bodyNode.asReturn();
       if ((function.isSetter || function.name == Names.INDEX_SET_NAME.text) &&
           returnStatement != null) {
         // Avoid encoding the implicit return of setters with arrow body:
@@ skipping 736 matching lines @@
       : this(null, true, node, initializers);
 
   accept(ir.Visitor v) => throw "unsupported";
 
   visitChildren(ir.Visitor v) => throw "unsupported";
 
   String toString() {
     return "IrFunction($kind, $isConstructor, $node, $initializers)";
   }
 }