Commented by: Tobias (tkloss)

I can confirm the bug:
var result = (from x in Context.Table select x).ToList();
works correct, but
var result = Context.Table.SqlQuery("SELECT * FROM TABLE").ToList();
fails with error: "Invalid attempt of read when the reader is closed."
This worked before with EF5.

Commented by: Tobias (tkloss)

This bug still exists in 4.1.0.0.

I played a bit with the sources. When using SqlQuery, the instance of FbCommand gets disposed before the containing FbDataReader is being accessed. That does not happen with a "normal" Linq-to-SQL query. After modifying the dispose method to not doing anything (just return), the query works correctly. Sure, this is not an acceptable solution, but it could help the experts to identify the underlying problem. I suppose it has something to do with the new async functionality of EF6.

Commented by: Tobias (tkloss)

Bug still exists in 4.5.0.0

The reason could be at this point in ObjectContext.cs of Entity Framework 6, method ExecuteStoreQueryInternal:

using (var command = CreateStoreCommand(commandText, parameters))
{
reader = command.ExecuteReader(...);
}
shaperFactory = InternalTranslate<TElement>(reader, ...);

After the using block, the FbCommand is disposed. Then the reader is accessed.
But in FbCommand, the reader is actively closed if the FbCommand gets disposed.

Commented by: @cincuranet

As it turns out, this is bug in EF: https://entityframework.codeplex.com/workitem/2418.