internal override SqlNode Visit(SqlNode node)
{
if (node == null)
{
return(null);
}
sourceExpression = node as SqlExpression;
if (sourceExpression != null)
{
Type type = sourceExpression.ClrType;
UnwrapStack unwrap = this.UnwrapSequences;
while (unwrap != null)
{
if (unwrap.Unwrap)
{
type = TypeSystem.GetElementType(type);
}
unwrap = unwrap.Last;
}
sourceType = type;
}
if (sourceType != null && TypeSystem.GetNonNullableType(sourceType).IsValueType)
{
return(node); // Value types can't also have a dynamic type.
}
if (sourceType != null && TypeSystem.HasIEnumerable(sourceType))
{
return(node); // Sequences can't be polymorphic.
}
switch (node.NodeType)
{
case SqlNodeType.ScalarSubSelect:
case SqlNodeType.Multiset:
case SqlNodeType.Element:
case SqlNodeType.SearchedCase:
case SqlNodeType.ClientCase:
case SqlNodeType.SimpleCase:
case SqlNodeType.Member:
case SqlNodeType.DiscriminatedType:
case SqlNodeType.New:
case SqlNodeType.FunctionCall:
case SqlNodeType.MethodCall:
case SqlNodeType.Convert: // Object identity does not survive convert. It does survive Cast.
// Dig no further.
return(node);
case SqlNodeType.TypeCase:
sourceType = ((SqlTypeCase)node).RowType.Type;
return(node);
case SqlNodeType.Link:
sourceType = ((SqlLink)node).RowType.Type;
return(node);
case SqlNodeType.Table:
sourceType = ((SqlTable)node).RowType.Type;
return(node);
case SqlNodeType.Value:
SqlValue val = (SqlValue)node;
if (val.Value != null)
{
// In some cases the ClrType of a Value node may
// differ from the actual runtime type of the value.
// Therefore, we ensure here that the correct type is set.
sourceType = val.Value.GetType();
}
return(node);
}
return(base.Visit(node));
}