`(0).div(0.0)` should be NaN; fix #3754

src/numeric.c

@@ -829,7 +829,7 @@ fix_divmod(mrb_state *mrb, mrb_value x)
     mrb_value a, b;
 
     flodivmod(mrb, (mrb_float)mrb_fixnum(x), mrb_to_flo(mrb, y), &div, &mod);
-    a = mrb_float_value(mrb, (mrb_int)div);
+    a = mrb_float_value(mrb, div);
     b = mrb_float_value(mrb, mod);
     return mrb_assoc_new(mrb, a, b);
   }