Merged in implementation of CSHARP-458 with one additional check to make sure cast doesn't fail.

Author: rstam

Driver/Linq/Expressions/ExpressionNormalizer.cs

@@ -82,15 +82,16 @@ protected override Expression VisitBinary(BinaryExpression node)
  }
  }
 
- //VB creates coalescing operations when dealing with nullable value comparisons, so we try and make this look like C#\
+ // VB creates coalescing operations when dealing with nullable value comparisons, so we try and make this look like C#
  if (node.NodeType == ExpressionType.Coalesce)
  {
  var right = node.Right as ConstantExpression;
- if (node.Left.NodeType == ExpressionType.Equal
- && node.Left.Type.IsGenericType 
- && node.Left.Type.GetGenericTypeDefinition() == typeof(Nullable<>) 
- && right != null 
- && (bool)right.Value == false)
+ if (node.Left.NodeType == ExpressionType.Equal &&
+ node.Left.Type.IsGenericType &&
+ node.Left.Type.GetGenericTypeDefinition() == typeof(Nullable<>) &&
+ right != null &&
+ right.Type == typeof(bool) &&
+ (bool)right.Value == false)
  {
  node = (BinaryExpression)node.Left;
  return Expression.MakeBinary(