merge revision(s) 57098: [Backport #13042]

re.c: non-regexp name reference

	* re.c (rb_reg_regsub): other than regexp has no name references.
  [ruby-core:78686] [Bug #13042]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_3@57349 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

re.c

@@ -3465,7 +3465,8 @@ rb_reg_regsub(VALUE str, VALUE src, struct re_registers *regs, VALUE regexp)
                 if (name_end < e) {
 		    VALUE n = rb_str_subseq(str, (long)(name - RSTRING_PTR(str)),
 					    (long)(name_end - name));
-		    if (!rb_enc_compatible(RREGEXP(regexp)->src, n) ||
+		    if (NIL_P(regexp) ||
+		        !rb_enc_compatible(RREGEXP(regexp)->src, n) ||
 			(no = name_to_backref_number(regs, regexp, name, name_end)) < 1) {
 			name_to_backref_error(n);
 		    }

test/ruby/test_string.rb

@@ -1483,6 +1483,10 @@ class TestString < Test::Unit::TestCase
     assert_equal(S("Abc"), S("abc").sub("a") {m = $~; "A"})
     assert_equal(S("a"), m[0])
     assert_equal(/a/, m.regexp)
+    bug = '[ruby-core:78686] [Bug #13042] other than regexp has no name references'
+    assert_raise_with_message(IndexError, /oops/, bug) {
+      'hello'.gsub('hello', '\k<oops>')
+    }
   end
 
   def test_sub!

version.h

@@ -1,6 +1,6 @@
 #define RUBY_VERSION "2.3.3"
 #define RUBY_RELEASE_DATE "2017-01-17"
-#define RUBY_PATCHLEVEL 233
+#define RUBY_PATCHLEVEL 234
 
 #define RUBY_RELEASE_YEAR 2017
 #define RUBY_RELEASE_MONTH 1