Dynamic dispatch weirdness in groovy

dispatch.groovy

//TEST DYNAMIC DISPATCH
trait TraitOne { }
abstract class TypeOne implements TraitOne { }
class TypeTwo extends TypeOne { }

def method(TraitOne _) { return 'traitOne' }
def method(TypeOne _) { return 'typeOne' }
def method(TypeTwo _) { return 'typeTwo' }

def method2(TraitOne _) { return 'traitOne' }
def method2(TypeOne _) { return 'typeOne' }

def method3(TypeOne _) { return 'typeOne' }

def object = new TypeTwo()

println "method1: ${method(object)}"
println "method2: ${method2(object)}"
println "method3: ${method3(object)}"

abstract class TypeThree {}
trait TraitTwo {}
class TypeFour extends TypeThree implements TraitTwo {}

def method4(TypeThree _) { return 'typeThree' }
def method4(TraitTwo _) { return 'traitTwo' }
def method4(TypeFour _) { return 'typeFour' }

def method5(TypeThree _) { return 'typeThree' }
def method5(TraitTwo _) { return 'traitTwo' }

def method6(TraitTwo _) { return 'traitTwo' }

def method7(TypeThree _) { return 'typeThree' }

def object2 = new TypeFour()

println "method4: ${method4(object2)}"
println "method5: ${method5(object2)}"
println "method6: ${method6(object2)}"
println "method7: ${method7(object2)}"

//OUTPUT:
//method1: typeTwo
//method2: traitOne
//method3: typeOne
//method4: typeFour
//method5: traitTwo
//method6: traitTwo
//method7: typeThree