[GROOVY-6408] Problem With @CompileStatic And Typed Collections

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.1.9, 2.3.0, 2.4.0-rc-1
• Fix Version/s: 4.0.0-alpha-3
• Component/s: Static Type Checker
• Assignee: Eric Milles
• Reporter: Jeff Brown
• Created: 30/Oct/13 10:48
• Updated: 03/Feb/22 22:43
• Resolved: 11/Oct/21 17:24

Description

The following code compiles:

Demo.groovy

@groovy.transform.CompileStatic
class Demo {
    def test(Listener listener1) {
        def listener2 = new DefaultListener()
        List<Listener> listeners = [listener1, listener2]
    }
}


interface Listener {}

class DefaultListener implements Listener {}

This also compiles:

Demo.groovy

@groovy.transform.CompileStatic
class Demo {
    def test(Listener listener1) {
        def listener2 = new DefaultListener()
        List<Listener> listeners = [listener1]
    }
}


interface Listener {}

class DefaultListener implements Listener {}

This will not compile:

Demo.groovy

@groovy.transform.CompileStatic
class Demo {
    def test(Listener listener1) {
        def listener2 = new DefaultListener()
        List<Listener> listeners = [listener2]
    }
}


interface Listener {}

class DefaultListener implements Listener {}

staticcompiledcollection $ groovy -version
Groovy Version: 2.1.9 JVM: 1.6.0_51 Vendor: Apple Inc. OS: Mac OS X
staticcompiledcollection $ 
staticcompiledcollection $ cat Demo.groovy 
@groovy.transform.CompileStatic
class Demo {
    def test(Listener listener1) {
        def listener2 = new DefaultListener()
        List<Listener> listeners = [listener2]
    }
}


interface Listener {}

class DefaultListener implements Listener {}
staticcompiledcollection $ 
staticcompiledcollection $ groovyc Demo.groovy 
org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
Demo.groovy: 5: [Static type checking] - Incompatible generic argument types. Cannot assign java.util.List <DefaultListener> to: java.util.List <Listener>
 @ line 5, column 36.
           List<Listener> listeners = [listener2]
                                      ^

1 error

staticcompiledcollection $