Assume that you have a large Microsoft SQL Server 2012 Reporting Services (SSRS 2012) or SSRS 2014 report that contains many expressions. When you upload the report to Reporting Services Report Manager, you may receive the following error message:
An unexpected error occurred while compiling expressions. Native compiler return value: '[BC30494] Line is too long.' (rsUnexpectedCompilerError).
Cumulative Update information
The issue was first fixed in the following cumulative update of SQL Server.
Each new cumulative update for SQL Server contains all the hotfixes and all the security fixes that were included with the previous cumulative update. We recommend that you download and install the latest cumulative updates for SQL Server:
To work around this issue, move sections of the report into a separate subreport so that each report uses less than 1000 text boxes.
CauseReports that contain many expressions can result in dynamically generated code lines with lengths that surpass the line length limitation enforced by the Visual Basic compiler.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.