[perl #53298] [BUG] inheritance not working?

# New Ticket Created by  dakkar
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parrot r27159, built on Linux, both x86-32 and x86-64

Running the attached program produces:

> 5
> Null PMC access in morph()
> current instr.: '!TYPECHECKEDASSIGN' pc 6754 (src/gen_builtins.pir:4728)
> called from Sub 'parrot;Bar;set' pc 255 (EVAL_13:94)
> called from Sub '_block10' pc 156 (EVAL_13:49)
> called from Sub 'parrot;PCT::HLLCompiler;eval' pc 785 (src/PCT/HLLCompiler
.pir:458)
> called from Sub 'parrot;PCT::HLLCompiler;evalfiles' pc 1067 (src/PCT/HLLCo
mpiler.pir:587)
> called from Sub 'parrot;PCT::HLLCompiler;command_line' pc 1246 (src/PCT/HL
LCompiler.pir:676)
> called from Sub 'parrot;Perl6::Compiler;main' pc 8860 (perl6.pir:183)

If I uncomment the $u.boo after the re-assignment to $u, I get a "Null
PMC access in get_string()"

It looks like inheritance is not working as I'd expect.

To make it "work", I have to move the 'set' method into Foo, and
remove all references to Bar.

--
Dakkar - <Mobilis in mobile>
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Hi,

dakkar (via RT) wrote:
> If I uncomment the $u.boo after the re-assignment to $u, I get a "Null
> PMC access in get_string()"
>
> It looks like inheritance is not working as I'd expect.
>
> To make it "work", I have to move the 'set' method into Foo, and
> remove all references to Bar.
>
Thanks for reporting. Initialization of attributes in parent classes
hadn't been implemented; I've done that today. However, the code wasn't
quite right. For attributes in parent classes, you must write them as an
auto-vivification closure of the parent.

$u=Bar.new(Foo{ :x(12) });

Which is implemented now. So now your example with that fix and the one
line uncommented gives:

5
12
9

As a bonus, if you try and do it the way you originally did, you will
now get a more helpful error message too.

This was done in a few patches, but r27268 is the final one that
actually gets your example running.

Thanks,

Jonathan