[GROOVY-10153] STC: cannot combine use-variance with bounded polymorphism

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.5.17, 3.0.11, 4.0.3
• Fix Version/s: 4.0.4, 3.0.20
• Component/s: Static compilation, Static Type Checker
• Assignee: Eric Milles
• Reporter: Stefanos Chaliasos
• Created: 28/Jun/21 17:21
• Updated: 27/Dec/23 18:22
• Resolved: 23/Jun/22 20:34

Description

I have the following Groovy program.

@groovy.transform.TypeChecked
class Test {
  public void m() {
    Foo<? super C> x = new Foo<B>();
  }

}

class A {}
class B extends A {}
class C extends B {}

class Foo<T extends A> {
}

Actual Behavior

The program does not compile, and I get the following error.

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
Test.groovy: 4: The type ? is not a valid substitute for the bounded parameter <T extends A>
 @ line 4, column 9.
       Foo<? super C> x = new Foo<B>();
           ^

1 error

Expected Behavior

Compile successfully.

Issue Links

• relates to: GROOVY-11258 AssertJ collection mapping is badly supported
• relates to: GROOVY-10756 STC: parameterized and bounded return value for java class property