anchor.diff:  
   intersectionOrPrimaryType
    : intersectionType
  - | primaryType
  + | primaryOrArray
  + ;
  +
  +primaryOrArray
  + : primaryType /* no line terminator here */ ('[' ']')+
    ;
   
   primaryType
  
positive.code: 
  LINE_COMMENT
     :   '//' ~[\r\n]* -> skip
     ;
negative.code: 
  /*arrayType
   ANTLR4 grammar taken from TypeScript Documentation:
   https://github.com/Microsoft/TypeScript/blob/master/doc/spec.md#12.1.2
   https://www.typescriptlang.org/docs/tutorial.html
   https://basarat.gitbooks.io/typescript/content/
  */
  
  grammar typescriptAmbientDeclarations;
  
  typescriptAmbientDeclarations
   : declarationSourceFile EOF
   ;
  
  