Fix wrong index offset for optional positionals with splat args

Author: mame

lib/typeprof/core/graph/box.rb

@@ -519,7 +519,7 @@ def pass_arguments(changes, genv, a_args)
           end
         end
         @f_args.opt_positionals.each_with_index do |f_vtx, i|
-          i += @f_args.opt_positionals.size
+          i += @f_args.req_positionals.size
           if i < start_rest
             changes.add_edge(genv, a_args.positionals[i], f_vtx)
           else

scenario/args/splat_with_opt.rb

@@ -0,0 +1,12 @@
+## update
+def foo(a, b, c, o1 = :default)
+  o1
+end
+
+ary = ["str"].to_a
+foo(:A, :B, :C, *ary)
+
+## assert
+class Object
+  def foo: (:A, :B, :C, ?:default | String) -> (:default | String)
+end