From 90311f37e47dd62ffad20c90db68a0705c050061 Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Fri, 21 Jul 2017 13:30:46 +0000
Subject: strscan.c: fix segfault in aref

* ext/strscan/strscan.c (strscan_aref): fix segfault after
  get_byte or getch which do not apply regexp.
  [ruby-core:82116] [Bug #13759]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59384 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 ext/strscan/strscan.c              |  1 +
 test/strscan/test_stringscanner.rb | 10 ++++++++++
 2 files changed, 11 insertions(+)

diff --git a/ext/strscan/strscan.c b/ext/strscan/strscan.c
index 838f0e7f86..75cff3716f 100644
--- a/ext/strscan/strscan.c
+++ b/ext/strscan/strscan.c
@@ -1034,6 +1034,7 @@ strscan_aref(VALUE self, VALUE idx)
             idx = rb_sym2str(idx);
             /* fall through */
         case T_STRING:
+            if (!p->regex) return Qnil;
             RSTRING_GETMEM(idx, name, i);
             i = name_to_backref_number(&(p->regs), p->regex, name, name + i, rb_enc_get(idx));
             break;
diff --git a/test/strscan/test_stringscanner.rb b/test/strscan/test_stringscanner.rb
index bc5db7900a..9fe6ad7125 100644
--- a/test/strscan/test_stringscanner.rb
+++ b/test/strscan/test_stringscanner.rb
@@ -718,4 +718,14 @@ class TestStringScanner < Test::Unit::TestCase
     s.scan(/test strin/)
     assert_equal('#<StringScanner 10/16 "...strin" @ "g tes...">', s.inspect)
   end
+
+  def test_aref_without_regex
+    s = StringScanner.new('abc')
+    s.get_byte
+    assert_nil(s[:c])
+    assert_nil(s["c"])
+    s.getch
+    assert_nil(s[:c])
+    assert_nil(s["c"])
+  end
 end
-- 
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