merge revision(s) 4f19666e8b144600e959e4673f79d63f98bd637d: [Backport #16508]

	`Regexp` in `MatchData` can be `nil`

	`String#sub` with a string pattern defers creating a `Regexp`
	until `MatchData#regexp` creates a `Regexp` from the matched
	string.  `Regexp#last_match(group_name)` accessed its content
	without creating the `Regexp` though.  [Bug #16508]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_6@67838 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 1 insertions, 0 deletions

diff --git a/re.c b/re.c
index 105c02a160..a86663034a 100644
--- a/re.c
+++ b/re.c
@@ -1936,6 +1936,7 @@ match_captures(VALUE match)
 static int
 name_to_backref_number(struct re_registers *regs, VALUE regexp, const char* name, const char* name_end)
 {
+    if (NIL_P(regexp)) return -1;
     return onig_name_to_backref_number(RREGEXP_PTR(regexp),
 	(const unsigned char *)name, (const unsigned char *)name_end, regs);
 }