[GROOVY-11115] Miss to check the compatibility of wildcard types

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Component/s: Static Type Checker
• Labels: wildcards
• Assignee: Unassigned
• Reporter: Thodoris Sotiropoulos
• Created: 28/Jun/23 07:57
• Updated: 28/Jun/23 07:57

Description

This might be a known issue / limitation.

I have the following code

import java.util.*

class Main {
  static final void test() {
    List<? extends Number> list = new LinkedList<Number>();
    List<Number> x = list; // types are not compatible.
    List<Number> y = (List<? extends Object>) null // types are not compatible;
    list.add(1); // method call is not permitted.
  }
}

Actual behavior

The code compiles without raising any errors.

Expected behavior

The compiler should have rejected the program by raising three type errors.

Notes

Tested against master