[lworld] RFR: Make "PrimitiveParameterizedClass.default" a poly expression. [v5]

Srikanth Adayapalam sadayapalam at openjdk.java.net
Mon Aug 2 11:44:50 UTC 2021

On Mon, 2 Aug 2021 11:07:20 GMT, Srikanth Adayapalam <sadayapalam at openjdk.org> wrote:

>> Jesper Steen Møller has updated the pull request incrementally with one additional commit since the last revision:
>>   Whitespace
> src/jdk.compiler/share/classes/com/sun/tools/javac/tree/TreeInfo.java line 295:
>> 293:             case TYPEAPPLY: return (JCTypeApply)tree;
>> 294:             case NEWCLASS: return getTypeApplication(((JCNewClass)tree).clazz);
>> 295:             case ANNOTATED_TYPE: return getTypeApplication(((JCAnnotatedType)tree).underlyingType);
> I think there is a copy + paste problem. We can never see a NEWCLASS here.  The LHS of .default is just a type node and cannot be an rvalue expression ==>  new X().default is illegal.

I think perhaps what we really need to do here is to attribute the clazz node of JCDefaultValue first - perhaps by first making a copy of the node and then see if it is a generic class but lacks type arguments. Such as this: 

    public void visitDefaultValue(JCDefaultValue that) {
        JCExpression copy = new TreeCopier<Void>(attr.make).copy(that.clazz);
        attr.attribType(copy, env);
        if (copy.type.getTypeArguments().isEmpty() && copy.type.tsym.type.isParameterized()) {
            processArg(that, speculativeTree -> new ResolvedDefaultType(that, env, speculativeTree));
        } else {
            //not a poly expression, just call Attr
            setResult(that, attr.attribTree(that, env, attr.unknownExprInfo));


PR: https://git.openjdk.java.net/valhalla/pull/369

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