This code:

package bug

class GroovyClass1 {
    def method1() {}
    def method2() {}
    def method3() {}
    def gonzo1() {}
    def gonzo2() {}
    def gonzo3() {}
}

class GroovyClass2 {
    def m2() {
        GroovyClass1 localClass = new GroovyClass1()
        localClass.
            

        new String().subst
    }
}

class GroovyClass3 {
    def m3() {
        println "Hi"
    }
}

Seems to break the sanatizer. The problem is the trailing dot in this line:

       localClass.

If you keep on adding and removing this dot you'll see. If it doesn't happen instantly add or remove a blank line to trigger a recompile.

A broken compilation unit leads to this:

AstUtilities.getRoot(request.info) == null