[GROOVY-10267] STC reports wrong message when encoutering wildcard types

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.5.17, 3.0.11, 4.0.2
• Component/s: Static Type Checker
• Assignee: Eric Milles
• Reporter: Thodoris Sotiropoulos
• Created: 27/Sep/21 13:52
• Updated: 24/Jul/22 12:19
• Resolved: 01/May/22 15:00

Description

I have the following program

class A<T> {
}
class B {
  A<? extends Object> test() {
    return test2();
  }
  A<? extends Object> test2() {
    return null;
  }
}

Actual behaviour

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
test.groovy: 6: [Static type checking] - Incompatible generic argument types. Cannot assign A<?> to: A<? extends java.lang.Object>
 @ line 6, column 12.
       return test2();
              ^1 error

Expected behaviour

Compile successfully

Tested against master

Issue Links

• relates to: GROOVY-10576 STC: map putAll fails to match "?" to "Object"