Compiler Error CS2019

Invalid target type for /target: must specify 'exe', 'winexe', 'library', or 'module'

The /target compiler option was used, but an invalid parameter was passed. To resolve this error, recompile the program using the form of the /target option that is appropriate to your output file.

The following sample generates CS2017:

// CS2019.cs
// compile with: /target:libra
// CS2019 expected
class MyClass