C# Error
CS1509 – The referenced file ‘{0}’ is not an assembly
Reason for the Error & Solution
Referenced file ‘file’ is not an assembly; use AddModules option instead
An output file (output file 1), produced in a compilation that used the module element of the (does not have an assembly manifest), was specified to . So, rather than appending an assembly to the assembly for the current program, the metadata information in output file 1 will be added to the assembly for the current program.