Use instanceof pattern matching

src/main/java/ch/njol/skript/effects/EffExit.java

@@ -118,13 +118,13 @@ protected TriggerItem walk(Event event) {
 				assert false : this;
 				return null;
 			}
-			if (node instanceof SectionExitHandler)
-				((SectionExitHandler) node).exit(event);
+			if (node instanceof SectionExitHandler exitHandler)
+				exitHandler.exit(event);
 
 			if (type == EVERYTHING || type == CONDITIONALS && node instanceof SecConditional || type == LOOPS && (node instanceof LoopSection))
 				i--;
 		}
-		return node instanceof LoopSection ? ((LoopSection) node).getActualNext() : node.getNext();
+		return node instanceof LoopSection ? node.getActualNext() : node.getNext();
 	}
 
 	@Override

src/main/java/ch/njol/skript/effects/EffReturn.java

@@ -109,14 +109,14 @@ protected TriggerItem walk(Event event) {
 
 		TriggerSection parent = getParent();
 		while (parent != null && parent != handler) {
-			if (parent instanceof SectionExitHandler)
-				((SectionExitHandler) parent).exit(event);
+			if (parent instanceof SectionExitHandler exitHandler)
+				exitHandler.exit(event);
 
 			parent = parent.getParent();
 		}
 
-		if (handler instanceof SectionExitHandler)
-			((SectionExitHandler) handler).exit(event);
+		if (handler instanceof SectionExitHandler exitHandler)
+			exitHandler.exit(event);
 
 		return null;
 	}

src/main/java/ch/njol/skript/lang/ExecutionIntent.java

@@ -99,7 +99,8 @@ private StopSections(int levels) {
 
 		@Override
 		public int compareTo(@NotNull ExecutionIntent other) {
-			if (!(other instanceof StopSections)) {return other.compareTo(this) * -1;}
+			if (!(other instanceof StopSections))
+				return other.compareTo(this) * -1;
 			int levels = ((StopSections) other).levels;
 			return Integer.compare(this.levels, levels);
 		}

src/main/java/ch/njol/skript/lang/ExpressionList.java

@@ -307,8 +307,8 @@ public Expression<? extends T>[] getExpressions() {
 	public List<Expression<? extends T>> getAllExpressions() {
 		List<Expression<? extends T>> expressions = new ArrayList<>();
 		for (Expression<? extends T> expression : this.expressions) {
-			if (expression instanceof ExpressionList<?>) {
-				expressions.addAll(((ExpressionList<? extends T>) expression).getAllExpressions());
+			if (expression instanceof ExpressionList<? extends T> innerList) {
+				expressions.addAll(innerList.getAllExpressions());
 				continue;
 			}
 			expressions.add(expression);

src/main/java/ch/njol/skript/sections/SecConditional.java

@@ -328,7 +328,7 @@ public ExecutionIntent triggerExecutionIntent() {
 	private TriggerItem getSkippedNext() {
 		TriggerItem next = getActualNext();
 		while (next instanceof SecConditional && ((SecConditional) next).type != ConditionalType.IF)
-			next = ((SecConditional) next).getActualNext();
+			next = next.getActualNext();
 		return next;
 	}
 
@@ -368,9 +368,7 @@ private static SecConditional getPrecedingConditional(List<TriggerItem> triggerI
 		// loop through the triggerItems in reverse order so that we find the most recent items first
 		for (int i = triggerItems.size() - 1; i >= 0; i--) {
 			TriggerItem triggerItem = triggerItems.get(i);
-			if (triggerItem instanceof SecConditional) {
-				SecConditional conditionalSection = (SecConditional) triggerItem;
-
+			if (triggerItem instanceof SecConditional conditionalSection) {
 				if (conditionalSection.type == ConditionalType.ELSE) {
 					// if the conditional is an else, return null because it belongs to a different condition and ends
 					// this one
@@ -391,10 +389,9 @@ private static List<SecConditional> getPrecedingConditionals(List<TriggerItem> t
 		// loop through the triggerItems in reverse order so that we find the most recent items first
 		for (int i = triggerItems.size() - 1; i >= 0; i--) {
 			TriggerItem triggerItem = triggerItems.get(i);
-			if (!(triggerItem instanceof SecConditional)) 
+			if (!(triggerItem instanceof SecConditional conditional)) 
 				 break;
-			SecConditional conditional = (SecConditional) triggerItem;
-			if (conditional.type == ConditionalType.ELSE)
+            if (conditional.type == ConditionalType.ELSE)
 				// if the conditional is an else, break because it belongs to a different condition and ends
 				// this one
 				break;
@@ -407,13 +404,12 @@ private static List<SecConditional> getElseIfs(List<TriggerItem> triggerItems) {
 		List<SecConditional> list = new ArrayList<>();
 		for (int i = triggerItems.size() - 1; i >= 0; i--) {
 			TriggerItem triggerItem = triggerItems.get(i);
-			if (triggerItem instanceof SecConditional) {
-				SecConditional secConditional = (SecConditional) triggerItem;
-
-				if (secConditional.type == ConditionalType.ELSE_IF)
+			if (triggerItem instanceof SecConditional secConditional) {
+                if (secConditional.type == ConditionalType.ELSE_IF) {
 					list.add(secConditional);
-				else
+				} else {
 					break;
+				}
 			} else {
 				break;
 			}

src/main/java/ch/njol/skript/sections/SecLoop.java

@@ -130,7 +130,7 @@ public boolean init(Expression<?>[] exprs,
 	protected TriggerItem walk(Event event) {
 		Iterator<?> iter = currentIter.get(event);
 		if (iter == null) {
-			iter = expr instanceof Variable ? ((Variable<?>) expr).variablesIterator(event) : expr.iterator(event);
+			iter = expr instanceof Variable<?> variable ? variable.variablesIterator(event) : expr.iterator(event);
 			if (iter != null) {
 				if (iter.hasNext())
 					currentIter.put(event, iter);
@@ -188,8 +188,8 @@ public void exit(Event event) {
 	}
 
 	private static boolean guaranteedToLoop(Expression<?> expression) {
-		if (expression instanceof Literal<?>)
-			return ((Literal<?>) expression).getAll().length > 0;
+		if (expression instanceof Literal<?> literal)
+			return literal.getAll().length > 0;
 		if (!(expression instanceof ExpressionList<?> list))
 			return false;