Fix AstExpressionVisitor to correctly handle switch + for.

src/ast-expression-visitor.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/ast-expression-visitor.h"
 
 #include "src/ast.h"
 #include "src/codegen.h"
@@ skipping 93 matching lines @@
 }
 
 
 void AstExpressionVisitor::VisitSwitchStatement(SwitchStatement* stmt) {
   RECURSE(Visit(stmt->tag()));
 
   ZoneList<CaseClause*>* clauses = stmt->cases();
 
   for (int i = 0; i < clauses->length(); ++i) {
     CaseClause* clause = clauses->at(i);
-    Expression* label = clause->label();
-    RECURSE(Visit(label));
+    if (!clause->is_default()) {
+      Expression* label = clause->label();
+      RECURSE(Visit(label));
+    }
     ZoneList<Statement*>* stmts = clause->statements();
     RECURSE(VisitStatements(stmts));
   }
 }
 
 
 void AstExpressionVisitor::VisitCaseClause(CaseClause* clause) {
   UNREACHABLE();
 }
 
 
 void AstExpressionVisitor::VisitDoWhileStatement(DoWhileStatement* stmt) {
   RECURSE(Visit(stmt->body()));
   RECURSE(Visit(stmt->cond()));
 }
 
 
 void AstExpressionVisitor::VisitWhileStatement(WhileStatement* stmt) {
   RECURSE(Visit(stmt->cond()));
   RECURSE(Visit(stmt->body()));
 }
 
 
 void AstExpressionVisitor::VisitForStatement(ForStatement* stmt) {
-  RECURSE(Visit(stmt->init()));
-  RECURSE(Visit(stmt->cond()));
-  RECURSE(Visit(stmt->next()));
+  if (stmt->init() != NULL) {
+    RECURSE(Visit(stmt->init()));
+  }
+  if (stmt->cond() != NULL) {
+    RECURSE(Visit(stmt->cond()));
+  }
+  if (stmt->next() != NULL) {
+    RECURSE(Visit(stmt->next()));
+  }
   RECURSE(Visit(stmt->body()));
 }
 
 
 void AstExpressionVisitor::VisitForInStatement(ForInStatement* stmt) {
   RECURSE(Visit(stmt->enumerable()));
   RECURSE(Visit(stmt->body()));
 }
 
 
@@ skipping 175 matching lines @@
 
 void AstExpressionVisitor::VisitSuperPropertyReference(
     SuperPropertyReference* expr) {}
 
 
 void AstExpressionVisitor::VisitSuperCallReference(SuperCallReference* expr) {}
 }
 
 
 }  // namespace v8::internal