@CompileStatic + Elvis operator cause null pointers to be thrown

package my.company
@Grab(group='org.codehaus.groovy', module='groovy-all', version='2.1.6')
import groovy.transform.CompileStatic

@CompileStatic
class Outer {
	
	public static void main(String[] args) {
		Inner inner
		int someInt = inner?.somestuff ?: 0
		println someInt
	}

	class Inner {
		int somestuff
	}
}