Miranda methods and Methods added by Code Generators
Andrew Dinn
adinn at redhat.com
Tue Aug 10 03:11:02 PDT 2010
On 08/10/2010 12:07 AM, John Rose wrote:
> If it weren't for explicit marks on this category of definitions in
> the bytecodes, it would be dangerous for the compiler to emit
> internal "helper" methods, fields, or classes. They would be visible
> to other classes (if not private) and to reflection. But they
> shouldn't be treated as if they were written or expected by the
> programmer.
Well, that's also true of some, if not all, of the code generated by
many bytecode transformers. As I remarked in an earlier note the
compiler tool chain is now much wider than just javac. However, these
other tools have have different requirements for visibility, perhaps
making SYNTHETIC unsuitable as a means of hiding behaviours which are
there as implementation mechanism.
In this present case, the subclass is failing to compile because its
(abstract) parent class has been transformed to include an interface and
a SYNTHETIC implementation of that interface. Since this transform is
meant to be a strictly local affair confined only to the parent class
this seems to be a case where use of SYNTHETIC should be appropriate.
The subclass honours the original class's requirements (it implements
abstract methods not introduced by the transformation) and it only
fails to honour those of the transformed class because the interface
method is visible but the SYNTHETIC parent class implementation is not.
Perhaps what is needed is for the interface to be SYNTHETIC or, at
least, for it's methods to be SYNTHETIC. Would this actually work? i.e.
assume we were to compile the interface and then bytecode transform it
so that either it or its methods were tagged with SYNTHETIC. If we then
place this and the transformed superclass in the classpath would the
checkOverride code still look for an implementation for the interface
method on the subclass or would it ignore the interface methods on the
assumption that they do not require validation?
regards,
Andrew Dinn
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