compiler accepts incompatible method reference for Sam conversion

[maurizio cimadamore]

On 16/07/2011 08:59, Ali Ebrahimi wrote:
> Hi,
> for me this still crash with full lambda repo build.
> The main reason for this, i think, is that hotspot sub-repo of lambda 
> repository is not sync with jdkb147(currently, latest tag is jdkb143).
Yeah - I noticed the weird tag in hotspot - I merged it against the JDK 
8 repo, which seems to have the same problem (all subrepos have b147 tag 
but hotspot, which has b143).
I will investigate about this.

Maurizio
>
> Best Regards,
> Ali Ebrahimi
>
> On Wed, Jul 13, 2011 at 1:22 PM, Maurizio Cimadamore 
> <maurizio.cimadamore at oracle.com 
> <mailto:maurizio.cimadamore at oracle.com>> wrote:
>
>     Ali,
>     this works for me (using b147 - or the VM bundled in the lambda
>     repo). There have been tons of fixes in the MH area lately, so
>     make sure you grab a more recent JDK 7 snapshot (I used to see
>     those problems too before the latest lambda merge, but now ost of
>     them went away).
>
>     Note also that, in cases in which 292 code is still unstable, you
>     can switch back to the old generation logic using the -XDuseProxy
>     flag, which should remove all 292-related problems (as, by doing
>     so, java.lang.reflect.Proxy will be used instead).
>
>     I will be pushing a fix for the other issue (incompatible method
>     ref erroneously accepted by javac) shortly.
>
>     Thanks
>     Maurizio
>
>
>     On 13/07/11 10:36, Ali Ebrahimi wrote:
>
>         Hi Remi,
>
>         On 7/13/11, Rémi Forax<forax at univ-mlv.fr
>         <mailto:forax at univ-mlv.fr>>  wrote:
>
>             On 07/13/2011 06:01 AM, Ali Ebrahimi wrote:
>
>             Hi Ali,
>
>             ...
>
>                 MethodHandle mh =
>                 MethodHandles.lookup().findStatic(MethodHandleTest.class,
>                 "sTest",
>                 MethodType.methodType(void.class,int.class,int.class));
>                 MethodHandle smh = mh.asSpreader(Object[].class,
>                 mh.type().parameterCount());
>
>                 smh.invoke(new Object[]{i,i});<===============crash
>
>                 main cause: mh.asSpreader
>
>                 I don't known this crash appears in jdkb147.
>
>             What you want here is to use asCollector, not asSpreader.
>             asSpreader requires that the method as already an object array
>             and extract the value from it.
>
>         May be i'm wrong. but this code picked from
>         MethodHandleProxies class
>
>             public static
>         <T>  T asInterfaceInstance(final Class<T>  intfc, final
>         MethodHandle target) {
>                 final Method sm = getSingleMethod(intfc);
>                 if (sm == null)
>                     throw new IllegalArgumentException("not a
>         single-method
>         interface: "+intfc.getName());
>                 MethodType smMT =
>         MethodType.methodType(sm.getReturnType(),
>         sm.getParameterTypes());
>                 MethodHandle checkTarget = target.asType(smMT);  //
>         make throw WMT
>                 checkTarget =
>         checkTarget.asType(checkTarget.type().changeReturnType(Object.class));
>                 final MethodHandle vaTarget =
>         checkTarget.asSpreader(Object[].class, smMT.parameterCount());
>                 return intfc.cast(Proxy.newProxyInstance(
>                         intfc.getClassLoader(),
>                         new Class[]{ intfc, WrapperInstance.class },
>                         new InvocationHandler() {
>                             private Object getArg(String name) {
>                                 if ((Object)name ==
>         "getWrapperInstanceTarget")  return target;
>                                 if ((Object)name ==
>         "getWrapperInstanceType")
>           return intfc;
>                                 throw new AssertionError();
>                             }
>                             public Object invoke(Object proxy, Method
>         method,
>         Object[] args) throws Throwable {
>                                 if (method.getDeclaringClass() ==
>         WrapperInstance.class)
>                                     return getArg(method.getName());
>                                 if (method.equals(sm))
>                                     return vaTarget.invokeExact(args);
>                                 if (isObjectMethod(method))
>                                     return callObjectMethod(this,
>         method, args);
>                                 throw new InternalError();
>                             }
>                         }));
>             }
>
>         and this results in this crash:
>         class MethodHandleTest{
>         ...
>         public static void sTest(int x,int y){
>              //   System.out.println("stest");
>             }
>
>           static interface Sam{
>                 void m(int x,int y);
>             }
>         ..
>         Sam sam = MethodHandleTest#sTest;
>                 sam.m(1,1);<==========
>
>             In your example, the call to mh.asSpreader should return a
>             runtime
>             exception,
>             I will investigate why it's not the case when I will be at
>             my office :)
>
>                 Best Regards,
>                 Ali Ebrahimi
>
>             regards,
>             Rémi
>
>
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>
>         Best Regards,
>         Ali Ebrahimi
>
>
>