Compared with null after type conversion using 'as' keyword

[SviatoslavRazmyslov]

V3019 Possibly an incorrect variable is compared to null after type conversion using 'as' keyword. Check variables 'value', 'valueExpression'. ExpressionMatcher.cs 62

public bool Matches(object value)
{
  var valueExpression = value as Expression;
  if (value == null) //<==
  {
    return false;
  }

  return ExpressionComparer.Default.Equals(this.expression, valueExpression);
}

It is most likely the object of the derived class that the programmer intended to check for null before using it. This is the fixed version of the code:

public bool Matches(object value)
{
  var valueExpression = value as Expression;
  if (valueExpression == null)
  {
    return false;
  }

  return ExpressionComparer.Default.Equals(this.expression, valueExpression);
}

This place is found by a static analyzer PVS-Studio.