@Grab and static compilation

[andresteingress]

It seems there is an issue with @Grab - getting strange static compilation errors for undefined parameters (those errors aren't present when doing a Gradle build or simple groovyc)

@Grab(group='org.gcontracts', module='gcontracts-core', version='[1.2.9,)')
import org.gcontracts.annotations.*

@groovy.transform.CompileStatic
@Invariant({ elements != null })
class Stack<T> {

    List<T> elements

    @Ensures({ is_empty() })
    def Stack()  {
        elements = []
    }

    @Requires({ preElements?.size() > 0 })
    @Ensures({ !is_empty() })
    def Stack(List<T> preElements)  {
        elements = preElements
    }

    boolean is_empty()  {
        elements.isEmpty()
    }

    @Requires({ !is_empty() })
    T last_item()  {
        elements.get(count() - 1)
    }

    def count() {
        elements.size()
    }

    @Ensures({ result == true ? count() > 0 : count() >= 0  })
    boolean has(T item)  {
        elements.contains(item)
    }

    @Ensures({ last_item() == item })
    def push(T item)  {
       elements.add(item)
    }

    @Requires({ !is_empty() })
    @Ensures({ last_item() == item })
    def replace(T item)  {
        remove()
        elements.add(item)
    }

    @Requires({ !is_empty() })
    @Ensures({ result != null })
    T remove()  {
        elements.remove(count() - 1)
    }

    String toString() { elements.toString() }
}

def stack = new Stack<Integer>()