[jira] [Resolved] (GROOVY-8757) Incorrect bytecode produced after compiling class implementing trait with generic method

["Paul King (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/GROOVY-8757?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Paul King resolved GROOVY-8757.
-------------------------------
       Resolution: Fixed
    Fix Version/s: 2.5.3
                   3.0.0-alpha-4
                   2.4.16

Proposed PR merged. Thanks for spotting the issue.

> Incorrect bytecode produced after compiling class implementing trait with generic method
> ----------------------------------------------------------------------------------------
>
>                 Key: GROOVY-8757
>                 URL: https://issues.apache.org/jira/browse/GROOVY-8757
>             Project: Groovy
>          Issue Type: Bug
>          Components: Compiler
>    Affects Versions: 2.4.15, 3.0.0-alpha-3, 2.5.2
>            Reporter: Daniil Ovchinnikov
>            Assignee: Paul King
>            Priority: Critical
>             Fix For: 2.4.16, 3.0.0-alpha-4, 2.5.3
>
>
> {code:java|title=T.groovy}
> trait T {
>     def <T extends Number> T foo(Class<T> c) {
>         println c
>         return null 
>     }
> }
> {code}
> {code:java|title=C.groovy}
> class C implements T {}
> {code}
> {code:java|title=usage.groovy}
> new C().foo(Integer)
> {code}
> {noformat}
> $ groovyc C.groovy T.groovy
> $ groovy usage.groovy
> class java.lang.Integer
> $ groovyc C.groovy # recompile C using already compiled T
> $ groovy usage.groovy
> Caught: java.lang.VerifyError: Bad return type
> Exception Details:
>   Location:
>     C.foo(Ljava/lang/Class;)Ljava/lang/Number; @5: areturn
>   Reason:
>     Type 'java/lang/Object' (current frame, stack[0]) is not assignable to 'java/lang/Number' (from method signature)
>   Current Frame:
>     bci: @5
>     flags: { }
>     locals: { 'C', 'java/lang/Class' }
>     stack: { 'java/lang/Object' }
>   Bytecode:
>     0x0000000: 2a2b b600 88b0
> java.lang.VerifyError: Bad return type
> Exception Details:
>   Location:
>     C.foo(Ljava/lang/Class;)Ljava/lang/Number; @5: areturn
>   Reason:
>     Type 'java/lang/Object' (current frame, stack[0]) is not assignable to 'java/lang/Number' (from method signature)
>   Current Frame:
>     bci: @5
>     flags: { }
>     locals: { 'C', 'java/lang/Class' }
>     stack: { 'java/lang/Object' }
>   Bytecode:
>     0x0000000: 2a2b b600 88b0
> 	at usage.run(usage.groovy:1)
> {noformat}
> {noformat:title=original javap output}
> public class C implements T,groovy.lang.GroovyObject {
>   public static transient boolean __$stMC;
>   public C();
>   public <T extends java.lang.Number> T foo(java.lang.Class<T>);
>   public <T extends java.lang.Number> T Ttrait$super$foo(java.lang.Class<T>);
>   static {};
>   protected groovy.lang.MetaClass $getStaticMetaClass();
>   public groovy.lang.MetaClass getMetaClass();
>   public void setMetaClass(groovy.lang.MetaClass);
>   public java.lang.Object invokeMethod(java.lang.String, java.lang.Object);
>   public java.lang.Object getProperty(java.lang.String);
>   public void setProperty(java.lang.String, java.lang.Object);
> }
> {noformat}
> {noformat:title=recompiled javap output}
> public class C implements T,groovy.lang.GroovyObject {
>   public static transient boolean __$stMC;
>   public C();
>   public <T> T foo(java.lang.Class<T>);
>   public <T extends java.lang.Number> T Ttrait$super$foo(java.lang.Class<T>);
>   static {};
>   protected groovy.lang.MetaClass $getStaticMetaClass();
>   public groovy.lang.MetaClass getMetaClass();
>   public void setMetaClass(groovy.lang.MetaClass);
>   public java.lang.Object invokeMethod(java.lang.String, java.lang.Object);
>   public java.lang.Object getProperty(java.lang.String);
>   public void setProperty(java.lang.String, java.lang.Object);
>   public java.lang.Number foo(java.lang.Class);
> }
> {noformat}



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