diff fixing NullPointerException method clone(Array:D) {} and method clone(Hash:D) {}

gistfile1.txt

diff --git a/src/core/Array.pm b/src/core/Array.pm
index 6fff8b91f..c435a9d51 100644
--- a/src/core/Array.pm
+++ b/src/core/Array.pm
@@ -51,14 +51,14 @@ my class Array { # declared in BOOTSTRAP
         nqp::stmts(
           (my \iter := self.iterator),
           (my \result := nqp::p6bindattrinvres(nqp::create(self),
-              Array, '$!descriptor', nqp::clone($!descriptor))),
+              Array, '$!descriptor', nqp::isnull($!descriptor) ?? Mu !! nqp::clone($!descriptor))),
           nqp::if(
             nqp::eqaddr(
               IterationEnd,
               iter.push-until-lazy:
                 my \target := ArrayReificationTarget.new(
                   (my \buffer := nqp::create(IterationBuffer)),
-                  nqp::clone($!descriptor))),
+                  nqp::isnull($!descriptor) ?? Mu !! nqp::clone($!descriptor))),
             nqp::p6bindattrinvres(result, List, '$!reified', buffer),
             nqp::stmts(
               nqp::bindattr(result, List, '$!reified', buffer),
diff --git a/src/core/Hash.pm b/src/core/Hash.pm
index 88739bcff..63068afda 100644
--- a/src/core/Hash.pm
+++ b/src/core/Hash.pm
@@ -43,7 +43,7 @@ my class Hash { # declared in BOOTSTRAP
           nqp::p6bindattrinvres(
             nqp::create(self),Map,'$!storage',
             nqp::clone(nqp::getattr(self,Map,'$!storage'))),
-          Hash, '$!descriptor', nqp::clone($!descriptor))
+          Hash, '$!descriptor', nqp::isnull($!descriptor) ?? Mu !! nqp::clone($!descriptor))
     }
 
     method !AT-KEY-CONTAINER(Str:D \key) is raw {