Add support for function references in _is_used_fully_qualified

Co-authored-by: oalders <[email protected]>

Author: Copilot

lib/App/perlimports/Document.pm

@@ -766,15 +766,15 @@ sub _is_used_fully_qualified {
                     )
                 )
                 || ( $_[1]->isa('PPI::Token::Symbol')
-                && $_[1] =~ m{\A[*\$\@\%]+${module_name}::[a-zA-Z0-9_]} );
+                && $_[1] =~ m{\A[&*\$\@\%]+${module_name}::[a-zA-Z0-9_]} );
         }
     );
 
     # We could combine the regexes, but this is easy to read.
     for my $key ( keys %{ $self->interpolated_symbols } ) {
 
         # package level variable
-        return 1 if $key =~ m{\A[*\$\@\%]+${module_name}::[a-zA-Z0-9_]+\z};
+        return 1 if $key =~ m{\A[&*\$\@\%]+${module_name}::[a-zA-Z0-9_]+\z};
 
         # function
         return 1 if $key =~ m/\A${module_name}::[a-zA-Z0-9_]+\z/;

t/function-reference.t

@@ -0,0 +1,34 @@
+use strict;
+use warnings;
+
+use lib 't/lib', 'test-data/lib';
+
+use Test::Differences qw( eq_or_diff );
+use TestHelper        qw( doc );
+use Test::More import => [qw( diag done_testing ok )];
+use Test::Needs qw( Cpanel::JSON::XS );
+
+my ( $doc, $log ) = doc(
+    filename        => 'test-data/function-reference.pl',
+    preserve_unused => 0,
+);
+
+ok(
+    $doc->_is_used_fully_qualified('Cpanel::JSON::XS'),
+    'find Cpanel::JSON::XS via function reference'
+);
+
+my $expected = <<'EOF';
+use strict;
+use warnings;
+
+use Cpanel::JSON::XS ();
+
+my $true_ref = \&Cpanel::JSON::XS::true;
+my $false_ref = \&Cpanel::JSON::XS::false;
+EOF
+
+eq_or_diff( $doc->tidied_document, $expected, 'function reference keeps module' )
+    || do { require Data::Dumper; diag Data::Dumper::Dumper($log); };
+
+done_testing;

test-data/function-reference.pl

@@ -0,0 +1,7 @@
+use strict;
+use warnings;
+
+use Cpanel::JSON::XS;
+
+my $true_ref = \&Cpanel::JSON::XS::true;
+my $false_ref = \&Cpanel::JSON::XS::false;