[GROOVY-3129] Compile-error when implementing a method from a generic interface

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.6-beta-1, 1.5.7, 1.6-beta-2
• Fix Version/s: 1.6-rc-1, 1.5.8, 1.7-beta-1
• Environment: sun java 1.6.0_u10, Linux (2.6.24)
• Assignee: Roshan Dawrani
• Reporter: Lukas Ruetz
• Created: 05/Nov/08 09:09
• Updated: 23/Dec/08 05:58
• Resolved: 08/Dec/08 15:11

Description

This code works under 1.5.6 but not with newer versions.

Test-Code:

class Test {
    static void main( args ) {
        Task t = new Task()
        List l = t.myCall()
        println l.dump()
    }
}

interface MyCallable<T> {
    T myCall() throws Exception;
}

class Task implements MyCallable<List> {
    List myCall() throws Exception {
        return [ 42 ]
    }
}

results in:

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed, /home/lukas/temp/groovytest2.groovy: 14: the return type is incompatible with java.lang.Object myCall() in MyCallable.
Node: org.codehaus.groovy.ast.MethodNode. At [14:5]  @ line 14, column 5.
       List myCall() throws Exception {
       ^