range.c: step in bignum

* range.c (range_step): honor step in bignum addition.
  [Feature #12912]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63208 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

range.c

@@ -408,7 +408,7 @@ range_step(int argc, VALUE *argv, VALUE range)
 	} while (FIXABLE(i));
 	b = LONG2NUM(i);
 
-	for (;; b = rb_funcallv(b, id_succ, 0, 0))
+	for (;; b = rb_big_plus(b, step))
 	    rb_yield(b);
     }
     else if (FIXNUM_P(b) && FIXNUM_P(e) && FIXNUM_P(step)) { /* fixnums are special */

test/ruby/test_range.rb

@@ -245,10 +245,13 @@ class TestRange < Test::Unit::TestCase
     (2**32-1 .. ).step(2) {|x| a << x; break if a.size == 2 }
     assert_equal([4294967295, 4294967297], a)
 
-    a = []
     max = RbConfig::LIMITS["FIXNUM_MAX"]
+    a = []
     (max..).step {|x| a << x; break if a.size == 2 }
     assert_equal([max, max+1], a)
+    a = []
+    (max..).step(max) {|x| a << x; break if a.size == 4 }
+    assert_equal([max, 2*max, 3*max, 4*max], a)
 
     o1 = Object.new
     o2 = Object.new