This method is only available on newer versions.
The first available version (v2_6_3) is shown here.
hash()
public
Compute a hash-value for this arithmetic sequence. Two arithmetic sequences
with same begin, end, step, and exclude_end?
values will generate the same hash-value.
See also Object#hash.
static VALUE
arith_seq_hash(VALUE self)
{
st_index_t hash;
VALUE v;
hash = rb_hash_start(arith_seq_exclude_end_p(self));
v = rb_hash(arith_seq_begin(self));
hash = rb_hash_uint(hash, NUM2LONG(v));
v = rb_hash(arith_seq_end(self));
hash = rb_hash_uint(hash, NUM2LONG(v));
v = rb_hash(arith_seq_step(self));
hash = rb_hash_uint(hash, NUM2LONG(v));
hash = rb_hash_end(hash);
return ST2FIX(hash);
}