Re: Not inlining 'new' for Foo since it has method modifiers which would be lost if it were inlined

On Fri, Feb 24, 2012 at 6:28 AM, Bill Moseley <[email protected]> wrote:
> Could someone please explain what's happening here?
>
> $ perl -MThrowable::Error -le 'package Foo; use Moose; extends
> "Throwable::Error"; Foo->meta->make_immutable'
> Not inlining 'new' for Foo since it has method modifiers which would be
> lost if it were inlined
>
> I see that not calling make_immutable avoids the warning, but I'm not
> understanding why.

The answer is in the error message. Something in the constructor for
Foo is wrapping 'new' in a method modifier and if you were to inline
that it would get lost. Since *you* aren't doing it, the answer lies
somewhere else. Throwable::Error is your parent class, so it's safe to
assume we're using it's new ... and Throwable::Error explicitly passes
inline_constructor => 1 to make_immutable to stop inlining the
constructor. So a bit more digging into the two roles that
Throwable::Error composes leads to:

https://metacpan.org/source/RJBS/Throwable-0.102080/lib/StackTrace/Auto.pm#L71

In which we find 'around new => { ... }'. Which is exactly the method
modifier that Moose is warning about.

-Chris