[GROOVY-11129] STC chooses to call a non-polymorphic method although explicit type arguments are given

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Duplicate
• Component/s: Static Type Checker
• Labels: overloading
• Assignee: Unassigned
• Reporter: Thodoris Sotiropoulos
• Created: 19/Jul/23 13:54
• Updated: 20/Jul/23 14:50
• Resolved: 20/Jul/23 14:47

Description

I have the following code:

import java.util.concurrent.*;

class Main {
  static final void test() {
    ExecutorService z = null;
    Future<CharSequence> future = z.<CharSequence>submit(() -> "fd");
  }
}

Actual behavior

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
Main.groovy: 7: [Static type checking] - Incompatible generic argument types. Cannot assign java.util.concurrent.Future<? extends java.lang.Object> to: java.util.concurrent.Future<java.lang.CharSequence>
 @ line 7, column 35.
       Future<CharSequence> future = z.<CharSequence>submit(() -> "fd");
                                     ^

1 error

Expected behavior

Compile successfully

Notes

It seems that the compiler chooses to call the variant that takes no type arguments (see https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/concurrent/ExecutorService.html#submit(java.lang.Runnable), even though explicit type arguments are given.

Issue Links

• duplicates: GROOVY-10714 STC: Callable, Runnable, Serializable overload preference for functional argument (closure, lambda, etc.)