RFR - JDK-8218650: LineNumberTable records for method invocations with arguments

[Liam Miller-Cushon]

For what it's worth I filed JDK-8218650 after a real debugging session
where I spent a while trying to understand an 'impossible' NPE before
realizing it was actually happening on the next line. So anecdotally at
leave one moderately savvy consumer of debug info would have benefited from
the extra LNT entries :)

The approach in JDK-8218628 sounds very promising, though. That information
would have been sufficient in the example that motivated JDK-8218650.

> e.g. access to fields in different classes with same name :-)

Won't that be an issue even if javac starts emitting LNT entries for field
accesses *and* the NPE messages get more detailed?

i.e. you could also have `b.b.b` and even if we know the line and that `b`
was involved it's ambiguous which dereference failed. (If the NPE message
included a qualified name of `b` that would be sufficient except for some
really pathological cases.)

Another option for improving the message for `b.b.b` would be to include a
column number, which was discussed in JDK-8020204.

On Thu, Feb 21, 2019 at 10:59 AM Maurizio Cimadamore <
maurizio.cimadamore at oracle.com> wrote:

> Yeah - I was afraid that will be the case.
>
> And I'm wondering what happens in cases where you have stuff like
>
> b.
>    b.
>       b.
>
> e.g. access to fields in different classes with same name :-)
>
> Of course a corner case, but...
>
> Maurizio
>
>
> On 21/02/2019 17:38, Vicente Romero wrote:
> > but it still refers to line 13, so it doesn't seem like it will
> > produce an exact reference to the actual line where the NPE happened
>
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