anchor.diff:      |   expression ('+'|'-') expression
       |   expression ('<' '<' | '>' '>' '>' | '>' '>') expression
       |   expression ('<=' | '>=' | '>' | '<') expression
  -    |   expression INSTANCEOF typeType
  +    |   expression INSTANCEOF type_
       |   expression ('==' | '!=' | '<>') expression
       |   expression '&' expression
       |   expression '^' expression
  
positive.code:     |   SUPER
      |   literal
      |   Identifier
      |   typeType '.' CLASS
      |   VOID '.' CLASS
      |   nonWildcardTypeArguments (explicitGenericInvocationSuffix | THIS arguments)
      |   SoqlLiteral
  
negative.code:     ;
  
  localVariableDeclaration
      :   variableModifier* type_ variableDeclarators
      ;
  
  statement
  