diff -bu ./t/inherited.t~ ./t/inherited.t
--- ./t/inherited.t~	2012-10-31 10:07:25.000000000 +0100
+++ ./t/inherited.t	2018-01-09 11:41:18.000000000 +0100
@@ -87,7 +87,13 @@
 
 # dirty hack, emulate Class::C3::Componentised
 require ExtraInheritedGroups;
+my $was_readonly;
+if (Internals::SvREADONLY(@SuperInheritedGroups::ISA)) {
+    Internals::SvREADONLY(@SuperInheritedGroups::ISA, 0);
+    $was_readonly = 1;
+}
 unshift @SuperInheritedGroups::ISA, qw/ExtraInheritedGroups/;
+Internals::SvREADONLY(@SuperInheritedGroups::ISA, 1) if $was_readonly;
 
 # this comes from ExtraInheritedGroups
 is(SuperInheritedGroups->basefield, 'your extra base!');