I've just spend several hours, trying to find out why my multi-branch-pipeline project was failing until I found this problem using trial and error.

I have a multi-branch-pipeline with a shared library. That shared library is already in use with other projects and works fine. After copy & pasting some code to a new Jenkinsfile I was wondering why it did not work.

Faulty Jenkinsfile:

@Library('shared-lib@master')

testing.sayHello('World')

This causes the build to fail with:
org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
WorkflowScript: 3: unexpected token: testing @ line 3, column 1.
testing.sayHello('World')
^

When I edit my Jenkinsfile to:

@Library('shared-lib@master')

def anything = 'nothing'

testing.sayHello('World')

it executes without any error.