Arrays can't be used as references since Perl 5.22.

Index: lib/Psh/Strategy/Executable.pm
--- lib/Psh/Strategy/Executable.pm.orig
+++ lib/Psh/Strategy/Executable.pm
@@ -24,7 +24,7 @@ sub runs_before {
 }
 
 sub applies {
-	my $com= @{$_[2]}->[0];
+	my $com= ${$_[2]}[0];
 	my $executable= Psh::Util::which($com);
 	return $executable if defined $executable;
 	return '';