Fix warning when attribute for delegation does not have definition co…

…ntext

Changes

@@ -3,6 +3,11 @@ for, noteworthy changes.
 
 {{$NEXT}}
 
+  [BUG FIXES]
+
+  - Creating a Moose subclass of a Moo class with an attribute with a
+    delegation would cause a warning.
+
 2.2001   2017-01-29
 
   [TESTS]

dist.ini

@@ -358,6 +358,7 @@ IO::String                   = 0
 Locale::US                   = 0
 Module::CPANTS::Analyse      = 0.92
 Module::Refresh              = 0
+Moo                          = 0
 MooseX::MarkAsMethods        = 0
 MooseX::NonMoose             = 0
 PadWalker                    = 0

lib/Moose/Meta/Method/Delegation.pm

@@ -130,13 +130,19 @@ sub {
 }
 EOF
 
-    my $definition = $attr->definition_context;
     my $description
         = 'inline delegation in '
         . $self->package_name . ' for '
         . $attr->name . '->'
-        . $delegate
-        . " (attribute declared in $definition->{file} at line $definition->{line})";
+        . $delegate;
+
+    my $definition = $attr->definition_context;
+    # While all attributes created in the usual way (via Moose's has()) will
+    # define this, there's no guarantee that this must be defined. For
+    # example, when Moo inflates a class to Moose it does not define these (as
+    # of Moo 2.003).
+    $description .= " (attribute declared in $definition->{file} at line $definition->{line})"
+        if defined $definition->{file} && defined $definition->{line};
 
     return try {
         $self->_compile_code(

t/bugs/moo_delegation.t

@@ -0,0 +1,31 @@
+use strict;
+use warnings;
+use Test::More;
+
+use Test::Requires 'Moo', 'Test::Warnings';
+use Test::Warnings qw( warnings :no_end_test );
+
+{
+    package Foo;
+
+    use Moo;
+
+    has foo => (
+        is      => 'ro',
+        handles => ['bar'],
+    );
+}
+
+{
+    package Bar;
+
+    use Moose;
+
+    ::is_deeply(
+        [ ::warnings { extends 'Foo' } ],
+        [],
+        'no warnings when extending Moo class that has a delegation'
+    );
+}
+
+done_testing();