title: XText Turn on Backtracking Correctly
body: <p>I've got a large grammar in X-Text, and it's got some ambiguities. I'm fully aware of the problems this will cause, but I'd like to be able to test the grammar before I look at optimising it.</p>
  
  <p>I've been trying to turn on backtrack in the X-Text workflow, and can't seem to manage it. I've got the following code in my mwe2 file, under the main project:</p>
  
  <pre><code>language = StandardLanguage {
          fragment=parser.antlr.XtextAntlrGeneratorFragment2 auto-inject{
              options = {
                  backtrack= true
              }
          }
          fragment=idea.parser.antlr.XtextAntlrIDEAGeneratorFragment auto-inject{
              options={
                  backtrack=true
              }
          }
  ...
  </code></pre>
  
  <p>But I still get errors in the form:</p>
  
  <pre><code>error(211): ../org.xtext.example.CSPTest/src-gen/org/xtext/example/mydsl/parser/antlr/internal/InternalMyDsl.g:1183:2: [fatal] rule ruleAny has non-LL(*) decision due to recursive rule invocations reachable from alts 1,2.  Resolve by left-factoring or using syntactic predicates or using backtrack=true option.
  </code></pre>
  
  <p>How can I correctly turn on backtrack in order to prevent this?</p>