[GROOVY-6715] Traits, Force Override and generic types

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Not A Problem
• Component/s: Compiler
• Labels: traits
• Assignee: Cédric Champeau
• Reporter: Tim Yates
• Created: 17/Apr/14 05:11
• Updated: 17/Apr/14 10:39
• Resolved: 17/Apr/14 10:39

Description

The following works when run against the current master branch:

import groovy.transform.*

def a = [ 1, 2, 3, 4, 5 ]

trait Doubler {
    @ForceOverride
    Object next() {
        super.next() * 2
    }
}

class ListIterator implements Iterator<Integer> {
    @Delegate Iterator<Integer> iter
    
    ListIterator( List<Integer> list ) {
        iter = list.iterator()
    }
}

assert new ListIterator( a ).withTraits( Doubler ).collect() == [ 2, 4, 6, 8, 10 ]

But if you change the Doubler trait to the more correctly typed:

trait Doubler {
    @ForceOverride
    Integer next() {
        super.next() * 2
    }
}

It isn't used, and the result is [1, 2, 3, 4, 5] instead.

Not sure if this is a bug, or a gap in my understanding, but thought I'd put it here