Re-enable hyperop assignment metaops.

src/core/List.pm

@@ -131,7 +131,7 @@ class List does Positional {
         }
     }
 
-    method pop() {
+    method pop() is rw {
         my $elems = self.elems;
         fail '.pop from an infinite list NYI' if $!nextiter.defined;
         $elems > 0
@@ -168,7 +168,7 @@ class List does Positional {
         $rlist;
     }
 
-    method shift() {
+    method shift() is rw {
         # make sure we have at least one item, then shift+return it
         self.gimme(1) 
           ?? nqp::shift($!items) 

src/core/metaops.pm

@@ -43,7 +43,7 @@ sub METAOP_ZIP(\$op) {
             my $loop = 1;
             while $loop {
                 my @z = @l.map({ $loop = 0 unless $_; .shift });
-                take $rop(|@z) if $loop;
+                take-rw $rop(|@z) if $loop;
             }
         }
     }
@@ -138,7 +138,7 @@ multi sub hyper(\$op, \$a, \$b, :$dwim-left, :$dwim-right) {
                     ?? $y.new(hyper($op, $x, $y, :$dwim-left, :$dwim-right)).item
                     !! $op($x, $y))
         }
-    )
+    ).eager
 }
 
 multi sub hyper(\$op, \$a) {