Make .HOW on a role give back the metaclass, rather than pun the role…

… and give back the metaclass of the punned class. Correcting this also required fixing something that relied on the old broken behavior.

src/builtins/guts.pir

@@ -264,15 +264,18 @@ to find a real, non-subtype and stash that away for fast access later.
     real_type = refinee
   got_real_type:
 
-    # If it's an un-disambiguated role, dis-ambiguate.
-    $I0 = isa real_type, 'Perl6Role'
+    # Create subclass. If it's a role, pun it.
+    .local pmc parrot_class, type_obj, subset
+    type_obj = refinee
+    $I0 = isa type_obj, 'Perl6Role'
+    unless $I0 goto ambig_role_done
+    type_obj = type_obj.'!select'()
+  ambig_role_done:
+    $I0 = isa type_obj, 'P6role'
     unless $I0 goto role_done
-    real_type = real_type.'!select'()
+    type_obj = type_obj.'!pun'()
   role_done:
-
-    # Create subclass.
-    .local pmc parrot_class, subset
-    parrot_class = p6meta.'get_parrotclass'(refinee)
+    parrot_class = p6meta.'get_parrotclass'(type_obj)
     subset = subclass parrot_class
 
     # Override accepts.
@@ -291,6 +294,10 @@ to find a real, non-subtype and stash that away for fast access later.
     subset = p6meta.'register'(subset)
 
     # Mark it a subtype and stash away real type, refinee  and refinement.
+    $I0 = isa real_type, 'Perl6Role'
+    unless $I0 goto real_type_done
+    real_type = real_type.'!select'()
+  real_type_done:
     setprop subset, 'subtype_realtype', real_type
     setprop subset, 'subtype_refinement', refinement
     setprop subset, 'subtype_refinee', refinee

src/pmc/p6role.pmc

@@ -39,6 +39,8 @@ pmclass P6role extends Role need_ext dynpmc group perl6_group {
             return SUPER(name);
         if (Parrot_str_equal(interp, name, CONST_STRING(interp, "Scalar")))
             return SUPER(name);
+        if (Parrot_str_equal(interp, name, CONST_STRING(interp, "HOW")))
+            return SUPER(name);
         first_char = Parrot_str_substr(interp, name, 0, 1, NULL, 0);
         if (Parrot_str_equal(interp, first_char, CONST_STRING(interp, "!")))
             return SUPER(name);