anchor.diff:  
   expression:
   	primaryExpr
  -	| unaryExpr
  +	| unary_op = (
  +		PLUS
  +		| MINUS
  +		| EXCLAMATION
  +		| CARET
  +		| STAR
  +		| AMPERSAND
  +		| RECEIVE
  +	) expression
   	| expression mul_op = (
   		STAR
   		| DIV
  
positive.code: 	| IMAGINARY_LIT
  	| RUNE_LIT;
  
  operandName: IDENTIFIER (DOT IDENTIFIER)?;
  
  qualifiedIdent: IDENTIFIER DOT IDENTIFIER;
  
  
negative.code: 		| arguments
  	);
  
  
  conversion: nonNamedType L_PAREN expression COMMA? R_PAREN;
  
  nonNamedType: typeLit | L_PAREN nonNamedType R_PAREN;
  
  operand: literal | operandName | L_PAREN expression R_PAREN;
  
  