Make constructors explicit.

src/ast.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 524 matching lines @@
 
 class ModuleLiteral: public Module {
  public:
   DECLARE_NODE_TYPE(ModuleLiteral)
 
   Block* body() const { return body_; }
 
  protected:
   template<class> friend class AstNodeFactory;
 
-  ModuleLiteral(Block* body)
+  explicit ModuleLiteral(Block* body)
       : body_(body) {
   }
 
  private:
   Block* body_;
 };
 
 
 class ModuleVariable: public Module {
  public:
   DECLARE_NODE_TYPE(ModuleVariable)
 
   Variable* var() const { return var_; }
 
  protected:
   template<class> friend class AstNodeFactory;
 
-  ModuleVariable(Variable* var)
+  explicit ModuleVariable(Variable* var)
       : var_(var) {
   }
 
  private:
   Variable* var_;
 };
 
 
 class ModulePath: public Module {
  public:
@@ skipping 18 matching lines @@
 
 class ModuleUrl: public Module {
  public:
   DECLARE_NODE_TYPE(ModuleUrl)
 
   Handle<String> url() const { return url_; }
 
  protected:
   template<class> friend class AstNodeFactory;
 
-  ModuleUrl(Handle<String> url) : url_(url) {
+  explicit ModuleUrl(Handle<String> url) : url_(url) {
   }
 
  private:
   Handle<String> url_;
 };
 
 
 class IterationStatement: public BreakableStatement {
  public:
   // Type testing & conversion.
@@ skipping 2199 matching lines @@
  private:
   Isolate* isolate_;
   Zone* zone_;
   Visitor visitor_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_