6723444: javac fails to substitute type variables into a constructor's throws clause

[Mark Mahieu]

Hi, Maurizio.

On 23 Jul 2008, at 14:35, Maurizio Cimadamore wrote:
>
> The main issue here is that a JCNewClass node of the AST keeps only  
> track of the constructor symbol (which means that we have only  
> access to the 'formal' constructor, "<X extends Throwable> Hello 
> (Foo<X> foo) throws X" in this case). Since the actual type of the  
> constructor (the one with Exception in place of X) get lost during  
> attribution, there's no way to recover that info at a later point  
> during flow analysis.
>

Yes that matches my understanding.

> My fix basically consists in storing the actual type of the  
> constructor method inside the 'type' field of the constructor field  
> stored inside the AST node.

Hmm.  The Symbol held in the constructor field isn't unique for each  
new class expression (unless it's an anonymous class), so changing  
its type could cause problems.  For example, does the following  
compile with that approach?


public class Hello {
     static class Foo<X> {}

     <X extends Throwable> Hello(Foo<X> foo) throws X {}

     public static void main(String[] args) throws Throwable {
	new Hello(new Foo<Exception>());
	new Hello(new Foo<Throwable>());
     }
}


If I understood you correctly I think you'd get a 'cannot find  
symbol' error on the second constructor invocation.  Or have I  
misunderstood?

>
> Regards
> Maurizio
>

Regards,

Mark

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