[GROOVY-10291] STC fails to substitute type variable when using the diamond operator and calling a closure

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.0.0-beta-2, 2.5.19, 3.0.13
• Component/s: Static Type Checker
• Assignee: Eric Milles
• Reporter: Thodoris Sotiropoulos
• Created: 08/Oct/21 12:23
• Updated: 10/Sep/22 18:31
• Resolved: 02/Nov/21 00:55

Description

I have the following program

class A<X> {
  X x;
  A(X x) {
    this.x = x
  }
}


class Test<T> {

  void foo() {
    def closure = { T p -> "" }
    T y = null
    bar(new A<>(y).x) // works
    closure(new A<>(y).x) // fails
  }

  void bar(T x) {} 
}

Actual behavior

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
test.groovy: 15: [Static type checking] - Cannot call closure that accepts [T] with [X]
 @ line 15, column 12.
       closure(new A<>(y).x) // fails
              ^

1 error

Expected behaviour

Compile successfully

Tested against master