[GROOVY-10221] Unexpected compile-time error when combining closures and bounded type parameters

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.0.2
• Component/s: Static Type Checker
• Assignee: Eric Milles
• Reporter: Thodoris Sotiropoulos
• Created: 10/Sep/21 12:18
• Updated: 27/Apr/22 09:07
• Resolved: 14/Mar/22 11:32

Description

Program

 

class A<T1, T2 extends T1> {
  void foo() {
    def cls1 = { T2 x -> "" }
    Closure<T2> cls2 = { T2 x -> x }
    cls1(cls2((T2) null))
  }
}

Actual Behavior

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
test.groovy: 5: [Static type checking] - Cannot call closure that accepts [T2] with [T1]
 @ line 5, column 9.
       cls1(cls2((T2) null))
           ^1 error

Expected Behavior

Compile successfully