[GROOVY-10107] Cannot assign null to a variable with a bounded generic type

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.0.0-beta-1, 3.0.9, 2.5.19
• Component/s: Static Type Checker
• Assignee: Eric Milles
• Reporter: Thodoris Sotiropoulos
• Created: 25/May/21 13:46
• Updated: 11/Sep/22 16:25
• Resolved: 04/Jun/21 15:02

Description

I have the following program

final class Test<T extends Number> {
  final void m() {
    T v = null;
  }
}

Actual Behaviour

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
test.groovy: 5: [Static type checking] - Cannot assign value of type <unknown parameter type> to variable of type T
 @ line 5, column 11.
       T v = null;
             ^1 error

Expected Behaviour

 

Tested against master https://github.com/apache/groovy/commit/7a56d7130aaf7b5244fa5a82fa0505fb7509f51f