c.patch

diff --git src/core.c/Rakudo/Iterator.pm6 src/core.c/Rakudo/Iterator.pm6
index b3efa43d7..928b69467 100644
--- src/core.c/Rakudo/Iterator.pm6
+++ src/core.c/Rakudo/Iterator.pm6
@@ -828,14 +828,14 @@ method new(\n,\k,\b)
         method pull-one() {
             my int $n        = $!n;          # lexicals faster
             my int $k        = $!k;
-            my int $running  = 1;
             my $combination := $!combination;
             my $stack       := $!stack;
+            my int $index    = -1,
 
             nqp::while(
-              ($running && (my int $elems = nqp::elems($stack))),
+              (nqp::isne_i($index,$k) && (my int $elems = nqp::elems($stack))),
               nqp::stmts(
-                (my int $index = $elems - 1),
+                ($index = $elems - 1),
                 (my int $value = nqp::pop_i($stack)),
                 nqp::while(
                   nqp::islt_i($value,$n) && nqp::islt_i($index,$k),
@@ -846,7 +846,6 @@ method pull-one()
                     nqp::push_i($stack,$value)
                   )
                 ),
-                ($running = nqp::isne_i($index,$k)),
               )
             );