anchor.diff:  rust : crate ;
   
   // 5. Crates and source
  -crate : inner_attr* mod_item* { printf("crate!\n"); } ;
  +crate : inner_attr* mod_item* ;
   
   // 6. Items and Attributes
   /// 6.1 Items
  
positive.code: 
  // 8.1 Types
  ty
      : [ '(' [ ')' | ty [ ',' ty ]+ ')' ]
      | '~' ty
      | '*' MUT? ty
      | '[' ty fixed_vstore ']'
  
negative.code:            | '!' macro
             ]
      | lit_no_unit // regular 'lit' includes unit expr which is handled above
      ;
  
  /// 7.2.4 Structure expressions
  