[GROOVY-7061] Type inference not working for Collections.sort()

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.3.6, 2.4.5
• Fix Version/s: 2.5.0-beta-3, 2.6.0-alpha-3, 2.4.14, 3.0.0-alpha-2
• Component/s: Static Type Checker
• Assignee: Daniel Sun
• Reporter: Peter Ledbrook
• Created: 08/Sep/14 11:09
• Updated: 13/Dec/17 04:55
• Resolved: 13/Dec/17 04:55

Description

In this example:

import groovy.transform.TypeChecked

doIt()

@TypeChecked
void doIt() {
    List<Integer> nums = [1, 2, 3, -2, -5, 6]
//    nums.sort { a, b -> a.abs() <=> b.abs() }
    Collections.sort(nums, { a, b -> a.abs() <=> b.abs() })
}

the type checking fails on the closure arguments (no method abs() on type Object). Interestingly, it works fine for the line that's commented out.