[GROOVY-10316] Type variable inference does not work properly in nested diamond operators

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.11
• Fix Version/s: 4.0.3, 2.5.18, 3.0.12
• Component/s: Static Type Checker
• Assignee: Eric Milles
• Reporter: Thodoris Sotiropoulos
• Created: 18/Oct/21 14:24
• Updated: 23/Jul/22 21:07
• Resolved: 17/May/22 18:40

Description

I have the following program

class A<T> {
  T f;
  A(T f) {
    this.f = f;
  }
}

class B<T> {
  A<T> f;
  B(A<T> f) {
    this.f = f;
  }
}

class Test {
  void test() {
    def x = new  B<>(new A<>((long) 1)).f;
    A<Long> y = x;
  }
  
}

Actual behaviour

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
test.groovy: 18: [Static type checking] - Incompatible generic argument types. Cannot assign A<java.lang.Object> to: A<java.lang.Long>
 @ line 18, column 17.
       A<Long> y = x;
                   ^

1 error

Expected behaviour

Compile successfully

Tested against master