fix: Use wildcard type in CtUnaryOperator get/setOperand

src/main/java/spoon/reflect/code/CtUnaryOperator.java

@@ -31,13 +31,13 @@ public interface CtUnaryOperator<T> extends CtExpression<T>, CtStatement {
 	 * Gets the expression to which the operator is applied.
 	 */
 	@PropertyGetter(role = EXPRESSION)
-	CtExpression<T> getOperand();
+	CtExpression<?> getOperand();
 
 	/**
 	 * Sets the expression to which the operator is applied.
 	 */
 	@PropertySetter(role = EXPRESSION)
-	<C extends CtUnaryOperator> C setOperand(CtExpression<T> expression);
+	<C extends CtUnaryOperator> C setOperand(CtExpression<?> expression);
 
 	/**
 	 * Sets the kind of this operator.

src/main/java/spoon/support/reflect/code/CtUnaryOperatorImpl.java

@@ -29,15 +29,15 @@ public class CtUnaryOperatorImpl<T> extends CtExpressionImpl<T> implements CtUna
 	String label;
 
 	@MetamodelPropertyField(role = EXPRESSION)
-	CtExpression<T> operand;
+	CtExpression<?> operand;
 
 	@Override
 	public void accept(CtVisitor visitor) {
 		visitor.visitCtUnaryOperator(this);
 	}
 
 	@Override
-	public CtExpression<T> getOperand() {
+	public CtExpression<?> getOperand() {
 		return operand;
 	}
 
@@ -76,7 +76,7 @@ public <C extends CtStatement> C insertBefore(CtStatementList statements) {
 	}
 
 	@Override
-	public <C extends CtUnaryOperator> C setOperand(CtExpression<T> expression) {
+	public <C extends CtUnaryOperator> C setOperand(CtExpression<?> expression) {
 		if (expression != null) {
 			expression.setParent(this);
 		}