.WHO support; make sure we don't ever hand back a C NULL.

Author: jnthn

src/NQP/Actions.pm

@@ -1040,11 +1040,13 @@ method dotty($/) {
     }
     elsif $<longname> eq 'HOW' {
         $past.pirop('get_how PP');
-        $past.pasttype('pirop');
     }
     elsif $<longname> eq 'WHAT' {
         $past.pirop('get_what PP');
     }
+    elsif $<longname> eq 'WHO' {
+        $past.pirop('get_who PP');
+    }
     else {
         $past.name(~$<longname>);
         $past.pasttype('callmethod');

src/metamodel/rakudoobject.c

@@ -119,6 +119,7 @@ static INTVAL default_type_check (PARROT_INTERP, PMC *obj, PMC *checkee) {
 PMC * create_stable(PARROT_INTERP, PMC *REPR, PMC *HOW) {
     PMC *st_pmc = pmc_new_init(interp, stable_id, HOW);
     STABLE_STRUCT(st_pmc)->REPR = REPR;
+    STABLE_STRUCT(st_pmc)->WHO = PMCNULL;
     STABLE_STRUCT(st_pmc)->find_method = default_find_method;
     STABLE_STRUCT(st_pmc)->type_check = default_type_check;
     return st_pmc;