gistfile1.txt

diff --git a/src/core/Iterable.pm b/src/core/Iterable.pm
index b8f070a..c123e3a 100644
--- a/src/core/Iterable.pm
+++ b/src/core/Iterable.pm
@@ -151,4 +151,8 @@ my role Iterable {
     }
 }

+#?if jvm
+nqp::p6setitertype(Iterable);
+#?endif
+
 # vim: ft=perl6 expandtab sw=4
diff --git a/src/vm/jvm/Perl6/Ops.nqp b/src/vm/jvm/Perl6/Ops.nqp
index 26a8cec..7674a7d 100644
--- a/src/vm/jvm/Perl6/Ops.nqp
+++ b/src/vm/jvm/Perl6/Ops.nqp
@@ -90,6 +90,7 @@ $ops.add_hll_op('nqp', 'p6setbinder', -> $qastcomp, $op {
 });
 $ops.add_hll_op('perl6', 'p6trialbind', :!inlinable, $trial_bind);
 $ops.add_hll_op('nqp', 'p6trialbind', :!inlinable, $trial_bind);
+$ops.map_classlib_hll_op('perl6', 'p6setitertype', $TYPE_P6OPS, 'p6setitertype', [$RT_OBJ], $RT_OBJ, :tc);
 $ops.map_classlib_hll_op('perl6', 'p6isbindable', $TYPE_P6OPS, 'p6isbindable', [$RT_OBJ, $RT_OBJ], $RT_INT, :tc);
 $ops.map_classlib_hll_op('perl6', 'p6bindcaptosig', $TYPE_P6OPS, 'p6bindcaptosig', [$RT_OBJ, $RT_OBJ], $RT_OBJ, :tc);
 $ops.map_classlib_hll_op('perl6', 'p6typecheckrv', $TYPE_P6OPS, 'p6typecheckrv', [$RT_OBJ, $RT_OBJ, $RT_OBJ], $RT_OBJ, :tc);
@@ -217,6 +218,7 @@ $ops.add_hll_op('perl6', 'p6sink', -> $qastcomp, $past {
 $ops.add_hll_op('nqp', 'p6bool', $p6bool);
 $ops.map_classlib_hll_op('nqp', 'p6init', $TYPE_P6OPS, 'p6init', [], $RT_OBJ, :tc);
 $ops.map_classlib_hll_op('nqp', 'p6settypes', $TYPE_P6OPS, 'p6settypes', [$RT_OBJ], $RT_OBJ, :tc);
+$ops.map_classlib_hll_op('nqp', 'p6setitertype', $TYPE_P6OPS, 'p6setitertype', [$RT_OBJ], $RT_OBJ, :tc);
 $ops.map_classlib_hll_op('nqp', 'p6var', $TYPE_P6OPS, 'p6var', [$RT_OBJ], $RT_OBJ, :tc);
 $ops.map_classlib_hll_op('nqp', 'p6isbindable', $TYPE_P6OPS, 'p6isbindable', [$RT_OBJ, $RT_OBJ], $RT_INT, :tc);
 $ops.map_classlib_hll_op('nqp', 'p6inpre', $TYPE_P6OPS, 'p6inpre', [], $RT_INT, :tc);
diff --git a/src/vm/jvm/runtime/org/perl6/rakudo/Binder.java b/src/vm/jvm/runtime/org/perl6/rakudo/Binder.java
index 31d15d1..d8a0561 100644
--- a/src/vm/jvm/runtime/org/perl6/rakudo/Binder.java
+++ b/src/vm/jvm/runtime/org/perl6/rakudo/Binder.java
@@ -324,6 +324,7 @@ public final class Binder {
          * further checking. */
         SixModelObject decontValue = null;
         boolean didHLLTransform = false;
+        SixModelObject nomType = null;
         if (flag == CallSiteDescriptor.ARG_OBJ && !(is_rw && desiredNative != 0)) {
             /* We need to work on the decontainerized value. */
             decontValue = Ops.decont(arg_o, tc);
@@ -339,7 +340,7 @@ public final class Binder {
                 /* Is the nominal type generic and in need of instantiation? (This
                  * can happen in (::T, T) where we didn't learn about the type until
                  * during the signature bind). */
-                SixModelObject nomType = param.get_attribute_boxed(tc, gcx.Parameter,
+                nomType = param.get_attribute_boxed(tc, gcx.Parameter,
                     "$!nominal_type", HINT_nominal_type);
                 if ((paramFlags & SIG_ELEM_NOMINAL_GENERIC) != 0) {
                     SixModelObject HOW = nomType.st.HOW;
@@ -524,15 +525,25 @@ public final class Binder {
                  * container and store it, for copy or ro case (the rw bit
                  * in the container descriptor takes care of the rest). */
                 else {
-                    STable stScalar = gcx.Scalar.st;
-                    SixModelObject new_cont = stScalar.REPR.allocate(tc, stScalar);
-                    SixModelObject desc = param.get_attribute_boxed(tc, gcx.Parameter,
-                        "$!container_descriptor", HINT_container_descriptor);
-                    new_cont.bind_attribute_boxed(tc, gcx.Scalar, "$!descriptor",
-                        RakudoContainerSpec.HINT_descriptor, desc);
-                    new_cont.bind_attribute_boxed(tc, gcx.Scalar, "$!value",
-                        RakudoContainerSpec.HINT_value, decontValue);
-                    cf.oLex[sci.oTryGetLexicalIdx(varName)] = new_cont;
+                    boolean wrap = (paramFlags & SIG_ELEM_IS_COPY) != 0;
+                    if (!wrap && nomType != null && gcx.Iterable != null) {
+                        wrap = Ops.istype(gcx.Iterable, nomType, tc) != 0
+                            || Ops.istype(nomType, gcx.Iterable, tc) != 0;
+                    }
+                    if (wrap || varName.equals("$_")) {
+                        STable stScalar = gcx.Scalar.st;
+                        SixModelObject new_cont = stScalar.REPR.allocate(tc, stScalar);
+                        SixModelObject desc = param.get_attribute_boxed(tc, gcx.Parameter,
+                            "$!container_descriptor", HINT_container_descriptor);
+                        new_cont.bind_attribute_boxed(tc, gcx.Scalar, "$!descriptor",
+                            RakudoContainerSpec.HINT_descriptor, desc);
+                        new_cont.bind_attribute_boxed(tc, gcx.Scalar, "$!value",
+                            RakudoContainerSpec.HINT_value, decontValue);
+                        cf.oLex[sci.oTryGetLexicalIdx(varName)] = new_cont;
+                    }
+                    else {
+                        cf.oLex[sci.oTryGetLexicalIdx(varName)] = decontValue;
+                    }
                 }
             }
         }
diff --git a/src/vm/jvm/runtime/org/perl6/rakudo/RakOps.java b/src/vm/jvm/runtime/org/perl6/rakudo/RakOps.java
index 5fe919f..902ec30 100644
--- a/src/vm/jvm/runtime/org/perl6/rakudo/RakOps.java
+++ b/src/vm/jvm/runtime/org/perl6/rakudo/RakOps.java
@@ -37,6 +37,7 @@ public final class RakOps {
         public SixModelObject Str;
         public SixModelObject List;
         public SixModelObject ListIter;
+        public SixModelObject Iterable;
         public SixModelObject Array;
         public SixModelObject Nil;
         public SixModelObject Map;
@@ -87,6 +88,12 @@ public final class RakOps {
         }
         return null;
     }
+
+    public static SixModelObject p6setitertype(SixModelObject type, ThreadContext tc) {
+        GlobalExt gcx = key.getGC(tc);
+        gcx.Iterable = type;
+        return type;
+    }

     public static SixModelObject p6settypes(SixModelObject conf, ThreadContext tc) {
         GlobalExt gcx = key.getGC(tc);
@@ -101,6 +108,7 @@ public final class RakOps {
         gcx.Str = conf.at_key_boxed(tc, "Str");
         gcx.List = conf.at_key_boxed(tc, "List");
         gcx.ListIter = conf.at_key_boxed(tc, "ListIter");
+        gcx.Iterable = conf.at_key_boxed(tc, "Iterable");
         gcx.Array = conf.at_key_boxed(tc, "Array");
         gcx.Nil = conf.at_key_boxed(tc, "Nil");
         gcx.Map = conf.at_key_boxed(tc, "Map");