@@ -48,7 +48,7 @@ public static string Serialize(CalcNode node, CalcCategory category)
                 case UnaryCalcNode unary:
                 {
                     var value = FoldAngle(unary.Operand);
-                    return value is null ? null : unary.Negative ? -value.Value : value.Value;
+                    return value is null ? null : (double?)(unary.Negative ? -value.Value : value.Value);
                 }
 
                 case BinaryCalcNode binary when binary.Operator == '+' || binary.Operator == '-':
Original file line number	Diff line number	Diff line change
`@@ -48,7 +48,7 @@ public static string Serialize(CalcNode node, CalcCategory category)`
`48`	`48`	`case UnaryCalcNode unary:`
`49`	`49`	`{`
`50`	`50`	`var value = FoldAngle(unary.Operand);`
`51`		`- return value is null ? null : unary.Negative ? -value.Value : value.Value;`
	`51`	`+ return value is null ? null : (double?)(unary.Negative ? -value.Value : value.Value);`
`52`	`52`	`}`
`53`	`53`
`54`	`54`	`case BinaryCalcNode binary when binary.Operator == '+' \|\| binary.Operator == '-':`