Bring dispatcher up to date with latest handles dispatch fallback han…

…dling approach. Also, can't just go on truth for if we have a $!handles value because type objects are undefined and untrue. With this, we handle all the cases the alpha did again.

src/glue/dispatch.pir

@@ -306,6 +306,23 @@ Helper for handling calls of the form .$indirectthingy()
 .end
 
 
+=item !handles_dispatch_helper
+
+Helper for implementing delegation to a handles method.
+
+=cut
+
+.sub '!handles_dispatch_helper'
+    .param string methodname
+    .param string attrname
+    .param pmc self
+    .param pmc pos_args   :slurpy
+    .param pmc named_args :slurpy :named
+    $P0 = getattribute self, attrname
+    .tailcall $P0.methodname(pos_args :flat, named_args :flat :named)
+.end
+
+
 =item !deferal_fail
 
 Used by P6invocation to help us get soft-failure semantics when no deferal

src/metamodel/Attribute.nqp

@@ -84,7 +84,7 @@ method compose($package) {
     }
 
     # If we've a handles, pass it along to the handles setup helper.
-    if $!handles {
+    unless pir::isa__ips($!handles, 'Undef') {
         Rakudo::Guts.add_handles_method($package, $!name, $!handles);
     }
 }

src/pmc/p6opaque.pmc

@@ -125,7 +125,7 @@ static PMC *do_handles(PARROT_INTERP, PMC *cur_class, PMC *handlers, STRING *nam
         else {
             /* Use what we were given as something to smart-match against. */
             PMC    * const accepts_meth = VTABLE_find_method(interp, matcher, ACCEPTS_str);
-            PMC    * result             = PMCNULL;;
+            PMC    * result             = PMCNULL;
             Parrot_ext_call(interp, accepts_meth, "PiS->P", matcher, name, &result);
             if (VTABLE_get_bool(interp, result)) {
                 attr = VTABLE_get_string_keyed_str(interp, handles_hash, attrname);
@@ -141,16 +141,16 @@ static PMC *do_handles(PARROT_INTERP, PMC *cur_class, PMC *handlers, STRING *nam
 
     /* Did we find anything? */
     if (attr) {
-        /* Look up helper, clone it, attach names and return that. */
+        /* Look up helper, clone it, unshift names onto argument list and return. */
         PMC *sub = Parrot_ns_find_namespace_global(interp, Parrot_get_ctx_HLL_namespace(interp),
-                CONST_STRING(interp, "!HANDLES_DISPATCH_HELPER"));
+                CONST_STRING(interp, "!handles_dispatch_helper"));
+        PMC *call_sig = Parrot_pcc_get_signature(interp, CURRENT_CONTEXT(interp));
         PMC *boxed_attrname = pmc_new(interp, enum_class_String);
         PMC *boxed_methodname = pmc_new(interp, enum_class_String);
         VTABLE_set_string_native(interp, boxed_attrname, attr);
         VTABLE_set_string_native(interp, boxed_methodname, name);
-        sub = VTABLE_clone(interp, sub);
-        VTABLE_setprop(interp, sub, attrname_str, boxed_attrname);
-        VTABLE_setprop(interp, sub, methodname_str, boxed_methodname);
+        VTABLE_unshift_pmc(interp, call_sig, boxed_attrname);
+        VTABLE_unshift_pmc(interp, call_sig, boxed_methodname);
         return sub;
     }
     else {
@@ -245,11 +245,14 @@ PMC *look_for_method(PARROT_INTERP, PMC *search_list, INTVAL *start_pos, STRING
     if (PMC_IS_NULL(method)) {
         for (i = *start_pos; i < num_classes; i++) {
             PMC * const cur_class = VTABLE_get_pmc_keyed_int(interp, search_list, i);
-            PMC *handles = VTABLE_getprop(interp, cur_class, CONST_STRING(interp, "@!handles_dispatchers"));
-            if (!PMC_IS_NULL(handles)) {
-                method = do_handles(interp, cur_class, handles, name);
-                if (!PMC_IS_NULL(method))
-                    break;
+            PMC * const how       = VTABLE_getprop(interp, cur_class, metaclass_str);
+            if (!PMC_IS_NULL(how) && VTABLE_isa(interp, how, CONST_STRING(interp, "ClassHOW"))) {
+                PMC * handles = VTABLE_get_attr_str(interp, how, CONST_STRING(interp, "$!handles_dispatchers"));
+                if (!PMC_IS_NULL(handles)) {
+                    method = do_handles(interp, cur_class, handles, name);
+                    if (!PMC_IS_NULL(method))
+                        break;
+                }
             }
         }
     }