TypePtr AssignmentExpression::
inferTypesImpl(AnalysisResultPtr ar, TypePtr type, bool coerce,
               ExpressionPtr variable,
               ExpressionPtr value /* = ExpressionPtr() */) {
  TypePtr ret = type;
  if (value) {
    if (coerce) {
      ret = value->inferAndCheck(ar, type, coerce);
    } else {
      ret = value->inferAndCheck(ar, NEW_TYPE(Some), coerce);
    }
  }

  BlockScopePtr scope = ar->getScope();
  if (variable->is(Expression::KindOfConstantExpression)) {
    // ...as in ClassConstant statement
    ConstantExpressionPtr exp =
      dynamic_pointer_cast<ConstantExpression>(variable);
    bool p;
    scope->getConstants()->check(exp->getName(), ret, true, ar, variable, p);
  } else if (variable->is(Expression::KindOfDynamicVariable)) {
    // simptodo: not too sure about this
    ar->getFileScope()->setAttribute(FileScope::ContainsLDynamicVariable);
  } else if (variable->is(Expression::KindOfSimpleVariable)) {
    SimpleVariablePtr var = dynamic_pointer_cast<SimpleVariable>(variable);
    if (var->getName() == "this" && ar->getClassScope()) {
      if (ar->isFirstPass()) {
        ar->getCodeError()->record(variable, CodeError::ReassignThis,
                                   variable);
      }
    }
    if (ar->getPhase() == AnalysisResult::LastInference && value) {
      if (!value->getExpectedType()) {
        value->setExpectedType(variable->getActualType());
      }
    }
  }
  // if the value may involve object, consider the variable as "referenced"
  // so that objects are not destructed prematurely.
  bool referenced = true;
  if (value && value->isScalar()) referenced = false;
  if (ret && ret->isNoObjectInvolved()) referenced = false;
  if (referenced && variable->is(Expression::KindOfSimpleVariable)) {
    SimpleVariablePtr var =
      dynamic_pointer_cast<SimpleVariable>(variable);
    const std::string &name = var->getName();
    VariableTablePtr variables = ar->getScope()->getVariables();
    variables->addReferenced(name);
  }

  TypePtr vt = variable->inferAndCheck(ar, ret, true);
  if (!coerce && type->is(Type::KindOfAny)) {
    ret = vt;
  }

  return ret;
}
void AssignmentExpression::analyzeProgram(AnalysisResultPtr ar) {
  m_variable->analyzeProgram(ar);
  m_value->analyzeProgram(ar);
  if (ar->getPhase() == AnalysisResult::AnalyzeAll) {
    if (m_ref && m_variable->is(Expression::KindOfSimpleVariable)) {
      SimpleVariablePtr var =
        dynamic_pointer_cast<SimpleVariable>(m_variable);
      const std::string &name = var->getName();
      VariableTablePtr variables = ar->getScope()->getVariables();
      variables->addReferenced(name);
    }
    if (m_variable->is(Expression::KindOfConstantExpression)) {
      ConstantExpressionPtr exp =
        dynamic_pointer_cast<ConstantExpression>(m_variable);
      if (!m_value->isScalar()) {
        ar->getScope()->getConstants()->setDynamic(ar, exp->getName());
      }
    }
  }
}