diff --git a/string.c b/string.c
index c9383937ae..af02cdde51 100644
--- a/string.c
+++ b/string.c
@@ -3785,18 +3785,23 @@ rb_str_rindex_m(int argc, VALUE *argv, VALUE str)
* call-seq:
* str =~ obj -> integer or nil
*
- * Match---If obj is a Regexp, use it as a pattern to match
- * against str,and returns the position the match starts, or
- * nil
if there is no match. Otherwise, invokes
- * obj.=~, passing str as an argument. The default
- * =~
in Object returns nil
.
- *
- * Note: str =~ regexp
is not the same as
- * regexp =~ str
. Strings captured from named capture groups
- * are assigned to local variables only in the second case.
+ * Match---If obj is a Regexp, uses it as a pattern to match
+ * against the receiver, and returns the position the match starts,
+ * or +nil+ if there is no match. Otherwise, invokes obj.=~,
+ * passing the string as an argument.
+ * The default Object#=~ (deprecated) returns +nil+.
*
* "cat o' 9 tails" =~ /\d/ #=> 7
* "cat o' 9 tails" =~ 9 #=> nil
+ *
+ * Note that string =~ regexp
is not the same as
+ * regexp =~ string
. Strings captured from named capture groups
+ * are assigned to local variables only in the second case.
+ *
+ * "no. 9" =~ /(?\d+)/
+ * number #=> nil (not assigned)
+ * /(?\d+)/ =~ "no. 9"
+ * number #=> "9"
*/
static VALUE