Symptoms
Assume that you have a large Microsoft SQL Server 2012 Reporting Services (SSRS 2012) report that has many expressions. When you preview the report in Microsoft SQL Server 2012 Data Tools – Business Intelligence (SSDT-BI), you may receive the following error messages:
An error occurred during local report processing. The definition of the report '<Report Name>' is invalid. An unexpected error occurred while compiling expressions. Native Compiler return value '[BC30494] line is too long.' (rsUnexpectedCompilerError).
Resolution
This hotfix is included in the Microsoft SQL Server Data Tools - Business Intelligence for Visual Studio 2012, go to Microsoft Download Center to download Microsoft SQL Server Data Tools - Business Intelligence for Visual Studio 2012:
Download the package now.
For more information about how to download Microsoft support files, click the following article number to view the article in the Microsoft Knowledge Base:
119591 How to obtain Microsoft support files from online services Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help prevent any unauthorized changes to the file.
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.