Get deferal stuff back in place, to the degree we had it in alpha.

src/Perl6/Actions.pm

@@ -205,6 +205,9 @@ method newpad($/) {
     my $new_block := PAST::Block.new( PAST::Stmts.new(
         PAST::Op.new(
             :inline("    .local pmc true\n    true = get_hll_global 'True'")
+        ),
+        PAST::Var.new(
+            :name('__CANDIDATE_LIST__'), :scope('lexical'), :isdecl(1)
         )
     ));
     @BLOCK.unshift($new_block);

src/builtins/control.pir

@@ -209,6 +209,140 @@ src/builtins/control.pir - control flow related functions
     .return ($N0)
 .end
 
+
+=item callwith
+
+=cut
+
+.sub '&callwith'
+    .param pmc pos_args    :slurpy
+    .param pmc named_args  :slurpy :named
+
+    # For callwith, it's easy - just want to get the next candidate, call
+    # it and hand back it's return values. A tailcall does fine.
+    .local pmc clist, lexpad, self, next
+    get_next_candidate_info clist, $P0, lexpad
+    next = clone clist
+    next.'set_failure_mode'()
+    $P0 = deref next
+    $I0 = isa $P0, 'Method'
+    unless $I0 goto not_method
+    self = lexpad['self']
+    .tailcall next(self, pos_args :flat, named_args :flat :named)
+  not_method:
+    .tailcall next(pos_args :flat, named_args :flat :named)
+.end
+
+
+=item nextwith
+
+=cut
+
+.sub '&nextwith'
+    .param pmc pos_args    :slurpy
+    .param pmc named_args  :slurpy :named
+
+    # Find next candiate, invoke it and get its return value, then use
+    # return to return it as if it was from our original call.
+    .local pmc clist, lexpad, self, next, result
+    get_next_candidate_info clist, $P0, lexpad
+    next = clone clist
+    next.'set_failure_mode'()
+    $P0 = deref next
+    $I0 = isa $P0, 'Method'
+    unless $I0 goto not_method
+    self = lexpad['self']
+    (result) = next(self, pos_args :flat, named_args :flat :named)
+    goto process_result
+  not_method:
+    (result) = next(pos_args :flat, named_args :flat :named)
+
+  process_result:
+    $I0 = isa result, ['Failure']
+    unless $I0 goto did_defer
+    $P0 = result.'exception'()
+    if null $P0 goto did_defer
+    $S0 = $P0.'Str'()
+    if $S0 != 'No method to defer to' goto did_defer
+    .return (result)
+
+  did_defer:
+    $P0 = root_new ['parrot';'Exception']
+    $P0['type'] = .CONTROL_RETURN
+    setattribute $P0, 'payload', result
+    throw $P0
+.end
+
+
+=item callsame
+
+=cut
+
+.sub '&callsame'
+    # Find next candidate as well as caller and lexpad.
+    .local pmc clist, routine, lexpad, next
+    get_next_candidate_info clist, routine, lexpad
+    next = clone clist
+
+    # Build arguments based upon what the caller was originall invoked with,
+    # and tailcall the next candidate.
+    .local pmc pos_args, named_args
+    $P1 = lexpad['call_sig']
+    (pos_args, named_args) = '!deconstruct_call_sig'($P1)
+    next.'set_failure_mode'()
+    .tailcall next(pos_args :flat, named_args :flat :named)
+.end
+
+
+=item nextsame
+
+=cut
+
+.sub '&nextsame'
+    # Find next candidate as well as caller and lexpad.
+    .local pmc clist, routine, lexpad, next
+    get_next_candidate_info clist, routine, lexpad
+    next = clone clist
+
+    # Build arguments based upon what the caller was originall invoked with,
+    # get the result of the next candidate and use return to retrun from
+    # the caller, provided the defer did not fail.
+    .local pmc pos_args, named_args, result
+    $P1 = lexpad['call_sig']
+    (pos_args, named_args) = '!deconstruct_call_sig'($P1)
+    next.'set_failure_mode'()
+    (result) = next(pos_args :flat, named_args :flat :named)
+
+    $I0 = isa result, ['Failure']
+    unless $I0 goto did_defer
+    $P0 = result.'exception'()
+    if null $P0 goto did_defer
+    $S0 = $P0.'Str'()
+    if $S0 != 'No method to defer to' goto did_defer
+    .return (result)
+
+  did_defer:
+    $P0 = root_new ['parrot';'Exception']
+    $P0['type'] = .CONTROL_RETURN
+    setattribute $P0, 'payload', result
+    throw $P0
+.end
+
+
+=item lastcall
+
+Trims the candidate list so that nextsame/nextwith/callsame/callwith will
+find nothing more to call.
+
+=cut
+
+.sub '&lastcall'
+    # Find candidate list and trim it.
+    .local pmc clist
+    get_next_candidate_info clist, $P0, $P1
+    clist.'trim_candidate_list'()
+.end
+
 =back
 
 =cut

src/glue/dispatch.pir

@@ -253,3 +253,18 @@ there are none.
     concat $S0, "'"
     '&die'($S0)
 .end
+
+
+=item !deferal_fail
+
+Used by P6invocation to help us get soft-failure semantics when no deferal
+is possible.
+
+=cut
+
+.sub '!deferal_fail'
+    .param pmc pos_args    :slurpy
+    .param pmc named_args  :slurpy :named
+    .lex '__CANDIDATE_LIST__', $P0
+    .tailcall '!FAIL'('No method to defer to')
+.end

src/ops/perl6.ops

@@ -306,7 +306,7 @@ nextsame need.
 inline op get_next_candidate_info(out PMC, out PMC, out PMC) :base_core {
     PMC     *ctx         = Parrot_pcc_get_caller_ctx(interp, CURRENT_CONTEXT(interp));
     STRING  *name        = string_from_literal(interp, "__CANDIDATE_LIST__");
-    STRING  *wrapper     = string_from_literal(interp, "$!wrapper_block");
+    STRING  *wrapper     = string_from_literal(interp, "$!p6type");
     PMC     *last_lexpad = PMCNULL;
     PMC     *last_sub    = PMCNULL;
 
@@ -317,14 +317,8 @@ inline op get_next_candidate_info(out PMC, out PMC, out PMC) :base_core {
         if (!PMC_IS_NULL(clist)) {
             /* Found. Set results and we're done. */
             $1 = clist;
-            if (PMC_IS_NULL(VTABLE_getprop(interp, Parrot_pcc_get_sub(interp, ctx), wrapper))) {
-                $2 = Parrot_pcc_get_sub(interp, ctx);
-                $3 = lexpad;
-            }
-            else {
-                $2 = last_sub;
-                $3 = last_lexpad;
-            }
+            $2 = Parrot_pcc_get_sub(interp, ctx);
+            $3 = lexpad;
             break;
         }
         else {