[GROOVY-4939] groovyc compilation problem for return values with generics

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.8.1
• Fix Version/s: 1.8.2, 1.9-beta-3, 1.7.11
• Component/s: Compiler

Environment

sargis@sargis:~> uname -a
Linux sargis.webbfontaine.fr 2.6.37.6-0.5-desktop #1 SMP PREEMPT 2011-04-25 21:48:33 +0200 x86_64 x86_64 x86_64 GNU/Linux
sargis@sargis:~> java -version
java version "1.6.0_26"
Java(TM) SE Runtime Environment (build 1.6.0_26-b03)
Java HotSpot(TM) 64-Bit Server VM (build 20.1-b02, mixed mode)
sargis@sargis:~> groovy -version
Groovy Version: 1.8.1 JVM: 1.6.0_26
sargis@sargis:~>

• Assignee: Paul King
• Reporter: Sargis Harutyunyan
• Created: 21/Jul/11 15:35
• Updated: 07/Sep/11 14:13
• Resolved: 22/Jul/11 22:53

Description

Hi I have following code which was ok for groovy 1.8.0 but after updating to groovy 1.8.1 I have failed compilation

MessagingTask.groovy

class MessagingTask<T extends Serializable> {

  private static final long serialVersionUID = -5533069690405593263L;

  Long id
  String messageId
  String inDestination
  String outDestination
  MessagingTaskType messageType
  T messagePayload

  public String toString() {
    return "Task{" +
            "id=" + id +
            ", messageId='" + messageId + '\'' +
            ", inDestination='" + inDestination + '\'' +
            ", outDestination='" + outDestination + '\'' +
            ", messageType='" + messageType + '\'' +
            ", messagePayload=" + messagePayload +
            '}';
  }
}

MessagingTaskDatabase.groovy

class MessagingTaskDatabase {

    public List<MessagingTask<OutMessage>> loadOutMessage() {
        return new ArrayList<MessagingTask<OutMessage>>();
    }

}

SomeClient.java

List<MessagingTask<OutMessage>> messagingTasks = taskDatabase.loadOutMessage();

And the compile log:

    [mkdir] Created dir: /home/sargis/projects/twm_v3/trunk/twm_v3/accounting/Server/classes
  [groovyc] Compiling 185 source files to /home/sargis/projects/twm_v3/trunk/twm_v3/accounting/Server/classes
  [groovyc] org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
  [groovyc] Compile error during compilation with javac.
  [groovyc] /home/sargis/projects/twm_v3/trunk/twm_v3/accounting/Server/src/com/webbfontaine/twm/accounting/epaylog/scheduler/SendingScheduler.java:46: incompatible types
  [groovyc] found   : java.util.List<com.webbfontaine.twm.accounting.epaylog.emess.task.MessagingTask>
  [groovyc] required: java.util.List<com.webbfontaine.twm.accounting.epaylog.emess.task.MessagingTask<com.webbfontaine.twm.accounting.epaylog.emess.core.OutMessage>>
  [groovyc]         List<MessagingTask<OutMessage>> messagingTasks = taskDatabase.loadOutMessage();
  [groovyc]                                                                                     ^
  [groovyc] Note: Some input files use unchecked or unsafe operations.
  [groovyc] Note: Recompile with -Xlint:unchecked for details.
  [groovyc] 1 error
  [groovyc] 
  [groovyc] 
  [groovyc] 1 error

But if I remove generic type parameters from return and compilation is ok

public List loadOutMessage() {
    return new ArrayList<MessagingTask<OutMessage>>();
}