diff --git a/complex.c b/complex.c
index da69f9197c..3fbda125ff 100644
--- a/complex.c
+++ b/complex.c
@@ -354,15 +354,12 @@ VALUE rb_flo_is_infinite_p(VALUE num);
 inline static VALUE
 f_infinite_p(VALUE x)
 {
-    if (RB_INTEGER_TYPE_P(x)) {
+    if (RB_INTEGER_TYPE_P(x) || RB_TYPE_P(x, T_RATIONAL)) {
         return Qnil;
     }
     else if (RB_FLOAT_TYPE_P(x)) {
 	return rb_flo_is_infinite_p(x);
     }
-    else if (RB_TYPE_P(x, T_RATIONAL)) {
-        return Qnil;
-    }
     return rb_funcallv(x, id_infinite_p, 0, 0);
 }