[Bug #19175] p_kw without a sub pattern should be `assignable'

parse.y

@@ -4732,7 +4732,7 @@ p_kw		: p_kw_label p_expr
                     /*%%%*/
                         $$ = list_append(p, NEW_LIST(NEW_LIT(ID2SYM($1), &@$), &@$), assignable(p, $1, 0, &@$));
                     /*% %*/
-                    /*% ripper: rb_ary_new_from_args(2, get_value($1), Qnil) %*/
+                    /*% ripper: rb_ary_new_from_args(2, get_value(assignable(p, $1)), Qnil) %*/
                     }
                 ;
 

test/ripper/test_sexp.rb

@@ -502,6 +502,14 @@ eot
         [:aryptn, nil, nil, [:var_field, [:@ident, "a", [1, 13]]], nil],
         [[:var_ref, [:@ident, "a", [1, 17]]]],
         nil]],
+
+    [__LINE__, %q{ case 0; in {a:}; a; end } ] =>
+    [:case,
+      [:@int, "0", [1, 5]],
+      [:in,
+        [:hshptn, nil, [[[:@label, "a:", [1, 12]], nil]], nil],
+        [[:var_ref, [:@ident, "a", [1, 17]]]],
+          nil]],
   }
   pattern_matching_data.each do |(i, src), expected|
     define_method(:"test_pattern_matching_#{i}") do