Adding visitors to regurgitate expression types or reset them.

test/cctest/expression-type-collector.h

+// 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.
+
+#ifndef V8_EXPRESSION_TYPE_COLLECTOR_H_
+#define V8_EXPRESSION_TYPE_COLLECTOR_H_
+
+#include "src/ast-expression-visitor.h"
+
+namespace v8 {
+namespace internal {
+
+// A Visitor over a CompilationInfo's AST that collects
+// a human readable string summarizing structure and types.
+// Used for testing of the typing information attached to the
+// expression nodes of an AST.
+
+class ExpressionTypeCollector : public AstExpressionVisitor {
+ public:
+  static std::string Run(CompilationInfo* info);
+
+ protected:
+  void VisitExpression(Expression* expression);
+
+ private:
+  explicit ExpressionTypeCollector(CompilationInfo* info);
+
+  std::string types_;
+};
+}
+}  // namespace v8::internal
+
+#endif  // V8_EXPRESSION_TYPE_COLLECTOR_H_