[GROOVY-11012] Wrong type is inferred when calling method defined in the parent class

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 3.0.18, 4.0.12
• Component/s: Static Type Checker
• Labels: traits
• Assignee: Eric Milles
• Reporter: Thodoris Sotiropoulos
• Created: 13/Apr/23 16:19
• Updated: 23/Aug/23 09:07
• Resolved: 30/Apr/23 15:58

Description

I have the following program

interface Bar<V> {
  default V get(Object x, Object y) { return null; }
}

class Foo<V> implements Bar<V> {
  static <V> Foo<V> create() { return null; }
}

class Main {
  static final void test() {
    Number x = Foo.<Number>create().get(null, null);
  }

}

Actual behavior

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
test.groovy: 11: [Static type checking] - Cannot assign value of type java.lang.Object to variable of type java.lang.Number
 @ line 11, column 16.
       Number x = Foo.<Number>create().get(null, null);
                  ^

1 error

Expected behavior

Compile successfully

Notes

Tested against master (commit: 5bcd83e0fde722971f97d479f1a4d6da6cd4aa5f)

Test cased adapt from the following program that uses the Guava lib

import com.google.common.collect.HashBasedTable;

class Main {
  static final void test() {
    Number x = HashBasedTable.<Number, Number, Number>create().get(null, null);
  }
}

Issue Links

• is related to: GROOVY-8638 CompileStatic fails with Guava Multimap#asMap
• is related to: GROOVY-10120 STC: Guava Multimap#asMap bridge method
• relates to: GROOVY-11035 Inferred type is Object when having a complex inheritance chain of interfaces