All previous versions of SQL Server (including Reporting Services) introduced new RDL schema, which was not supported by current version of report viewer control (included in Visual Studio). Is it true also for version 2012?
For example SQL server 2008 R2 uses RDL 2010 but report viewer control for Visual Studio 2010 supports only RDL 2008 (used by SQL Server 2008).
Edit
It seems that SQL2012 uses the same reportbuilder (3.0) as SQL2008R2 Report Builder (SSRS). This could indicate that the schema is the same.
Note
RDL Schema version can be found in xmlns attribute of <Report>
element in .rdl file (usulaly second line of the .rdl file opened in text editor) see Find the Report Definition Schema Version (SSRS).