Fix handling of control/meta escapes in literal regexps

Ruby uses a recursive algorithm for handling control/meta escapes
in strings (read_escape).  However, the equivalent code for regexps
(tokadd_escape) in did not use a recursive algorithm.  Due to this,
Handling of control/meta escapes in regexp did not have the same
behavior as in strings, leading to behavior such as the following
returning nil:

```ruby
/\c\xFF/ =~ "\c\xFF"
```

Switch the code for handling \c, \C and \M in literal regexps to
use the same code as for strings (read_escape), to keep behavior
consistent between the two.

Fixes [Bug #14367]

1 files changed, 1 insertions, 1 deletions

diff --git a/spec/ruby/language/regexp/interpolation_spec.rb b/spec/ruby/language/regexp/interpolation_spec.rb
index ed0b724763..6951fd38ca 100644
--- a/spec/ruby/language/regexp/interpolation_spec.rb
+++ b/spec/ruby/language/regexp/interpolation_spec.rb
@@ -36,7 +36,7 @@ describe "Regexps with interpolation" do
 
   it "gives precedence to escape sequences over substitution" do
     str = "J"
-    /\c#{str}/.to_s.should == '(?-mix:\c#' + '{str})'
+    /\c#{str}/.to_s.should include('{str}')
   end
 
   it "throws RegexpError for malformed interpolation" do