anchor.diff:      ;
   
   fieldDecl
  -    : ({noTerminatorBetween(2)}? identifierList type | anonymousField) STRING_LIT?
  +    : ({noTerminatorBetween(2)}? identifierList type_ | anonymousField) STRING_LIT?
       ;
   
   anonymousField
  
positive.code: //MapType     = "map" "[" KeyType "]" ElementType .
  //KeyType     = Type .
  mapType
      : 'map' '[' type ']' elementType
      ;
  
  //ChannelType = ( "chan" | "chan" "<-" | "<-" "chan" ) ElementType .
  
negative.code: 
  //TypeSpec     = identifier Type .
  typeSpec
      : IDENTIFIER type_
      ;
  
  
  