File it as a bug report on the Moo RT. It should certainly be feasible; Moo could keep track of the line has occurs on, then use this when evaling the constructor. I've been doing some work on improving Moo exceptions thrown from isa and coerce in the last couple of weeks, so I'd be happy to add required to the list.

package Cow { use Moo; has name => (is => 'lazy', default => sub { 'Mooington' }) } say Cow->new->name

In reply to Re: Better error messages from Moo? by tobyink
in thread Better error messages from Moo? by szabgab

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