anchor.diff:      ;
   
   commCase
  -    : 'case' (sendStmt | recvStmt) | 'default'
  +    : 'case' (sendStmt | recvStmt)
  +    | 'default'
       ;
   
   recvStmt
  
positive.code: 
  receiverType
      : typeName
      | '(' '*' typeName ')'
      | '(' receiverType ')'
      ;
  
  expression
      : unaryExpr
  //    | expression BINARY_OP expression
      | expression ('||' | '&&' | '==' | '!=' | '<' | '<=' | '>' | '>=' | '+' | '-' | '|' | '^' | '*' | '/' | '%' | '<<' | '>>' | '&' | '&^') expression
      ;
  
  unaryExpr
      : primaryExpr
      | ('+'|'-'|'!'|'^'|'*'|'&'|'<-') unaryExpr
      ;
  
  conversion
      : type '(' expression ','? ')'
      ;
  
  eos
  
negative.code:     ;
  
  switchStmt
      : exprSwitchStmt
      | typeSwitchStmt
      ;
  
  exprSwitchStmt
  