MethodHandle.bindTo chain fails with "IllegalArgumentException: no leading reference parameter"

Maurizio Cimadamore maurizio.cimadamore at oracle.com
Tue Jul 25 17:30:18 UTC 2017


If you are using value types straight from source code (e.g. __Value), 
then yes, this appears to be a problem in javac. However, if you are 
just using value-capable classes, then javac shouldn't have much say in 
what you are trying to do, so, if that's the case it would point more in 
the MH direction.

Maurizio


On 25/07/17 18:21, Vladimir Ivanov wrote:
>> Changing
>>      MethodHandle mh2 = mh1.bindTo(test_vt);
>> to
>>      MethodHandle mh2 = MethodHandles.insertArguments(mh1, 0, test_vt);
>> fails with:
>>
>> Exception in thread "main" java.lang.ArrayStoreException: MyValue1
>>     at Test.test(Test.java:35)
>>     at Test.main(Test.java:41)
>>
>> Why's that?
>
> I'd say it's a problem in javac with auto-boxing of Q-types when 
> calling vararg methods.
>
> It tries to store a Q-typed value into an Object[] which generates an 
> ArrayStoreException:
>
>   long test() throws java.lang.Throwable;
> ...
>         10: iconst_1
>         11: anewarray     #7                  // class java/lang/Object
>         14: dup
>         15: iconst_0
>         16: aload_0
>         17: getfield      #3                  // Field test_vt:QMyValue1;
>         20: aastore
>         21: invokestatic  #8                  // Method 
> java/lang/invoke/MethodHandles.insertArguments:(Ljava/lang/invoke/MethodHandle;I[Ljava/lang/Object;)Ljava/lang/invoke/MethodHandle;
>
> Best regards,
> Vladimir Ivanov



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