Unreachable Code

src/main/java/ch/njol/skript/ScriptLoader.java

@@ -48,6 +48,7 @@
 import org.bukkit.event.Event;
 import org.eclipse.jdt.annotation.Nullable;
 import org.skriptlang.skript.lang.script.Script;
+import org.skriptlang.skript.lang.script.ScriptWarning;
 import org.skriptlang.skript.lang.structure.Structure;
 
 import java.io.File;
@@ -949,9 +950,10 @@ public static ArrayList<TriggerItem> loadItems(SectionNode node) {
 
 		if (Skript.debug())
 			parser.setIndentation(parser.getIndentation() + "    ");
-		
+
 		ArrayList<TriggerItem> items = new ArrayList<>();
 
+		boolean executionStops = false;
 		for (Node subNode : node) {
 			parser.setNode(subNode);
 
@@ -962,10 +964,11 @@ public static ArrayList<TriggerItem> loadItems(SectionNode node) {
 			if (!SkriptParser.validateLine(expr))
 				continue;
 
+			TriggerItem item;
 			if (subNode instanceof SimpleNode) {
 				long start = System.currentTimeMillis();
-				Statement stmt = Statement.parse(expr, items, "Can't understand this condition/effect: " + expr);
-				if (stmt == null)
+				item = Statement.parse(expr, items, "Can't understand this condition/effect: " + expr);
+				if (item == null)
 					continue;
 				long requiredTime = SkriptConfig.longParseTimeWarningThreshold.value().getMilliSeconds();
 				if (requiredTime > 0) {
@@ -978,34 +981,44 @@ public static ArrayList<TriggerItem> loadItems(SectionNode node) {
 				}
 
 				if (Skript.debug() || subNode.debug())
-					Skript.debug(SkriptColor.replaceColorChar(parser.getIndentation() + stmt.toString(null, true)));
+					Skript.debug(SkriptColor.replaceColorChar(parser.getIndentation() + item.toString(null, true)));
 
-				items.add(stmt);
+				items.add(item);
 			} else if (subNode instanceof SectionNode) {
 				TypeHints.enterScope(); // Begin conditional type hints
 
-				Section section = Section.parse(expr, "Can't understand this section: " + expr, (SectionNode) subNode, items);
-				if (section == null)
+				item = Section.parse(expr, "Can't understand this section: " + expr, (SectionNode) subNode, items);
+				if (item == null)
 					continue;
 
 				if (Skript.debug() || subNode.debug())
-					Skript.debug(SkriptColor.replaceColorChar(parser.getIndentation() + section.toString(null, true)));
+					Skript.debug(SkriptColor.replaceColorChar(parser.getIndentation() + item.toString(null, true)));
 
-				items.add(section);
+				items.add(item);
 
 				// Destroy these conditional type hints
 				TypeHints.exitScope();
+			} else {
+				continue;
+			}
+
+			if (executionStops
+					&& !SkriptConfig.disableUnreachableCodeWarnings.value()
+					&& parser.isActive()
+					&& !parser.getCurrentScript().suppressesWarning(ScriptWarning.UNREACHABLE_CODE)) {
+				Skript.warning("Unreachable code. The previous statement stops further execution.");
 			}
+			executionStops = item.executionIntent() != null;
 		}
-		
+
 		for (int i = 0; i < items.size() - 1; i++)
 			items.get(i).setNext(items.get(i + 1));
 
 		parser.setNode(node);
-		
+
 		if (Skript.debug())
 			parser.setIndentation(parser.getIndentation().substring(0, parser.getIndentation().length() - 4));
-		
+
 		return items;
 	}
 

src/main/java/ch/njol/skript/SkriptConfig.java

@@ -192,6 +192,7 @@ public static String formatDate(final long timestamp) {
 	public static final Option<Boolean> disableMissingAndOrWarnings = new Option<>("disable variable missing and/or warnings", false);
 	public static final Option<Boolean> disableVariableStartingWithExpressionWarnings =
 		new Option<>("disable starting a variable's name with an expression warnings", false);
+	public static final Option<Boolean> disableUnreachableCodeWarnings = new Option<>("disable unreachable code warnings", false);
 
 	@Deprecated
 	public static final Option<Boolean> enableScriptCaching = new Option<>("enable script caching", false)

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

@@ -23,13 +23,8 @@
 import ch.njol.skript.doc.Examples;
 import ch.njol.skript.doc.Name;
 import ch.njol.skript.doc.Since;
-import ch.njol.skript.lang.Effect;
-import ch.njol.skript.lang.Expression;
-import ch.njol.skript.lang.SectionExitHandler;
-import ch.njol.skript.lang.LoopSection;
+import ch.njol.skript.lang.*;
 import ch.njol.skript.lang.SkriptParser.ParseResult;
-import ch.njol.skript.lang.TriggerItem;
-import ch.njol.skript.lang.TriggerSection;
 import ch.njol.skript.lang.parser.ParserInstance;
 import ch.njol.skript.log.ErrorQuality;
 import ch.njol.skript.sections.SecConditional;
@@ -51,7 +46,7 @@
 		"\tset loop-block to water"
 })
 @Since("<i>unknown</i> (before 2.1)")
-public class EffExit extends Effect { // TODO [code style] warn user about code after a stop effect
+public class EffExit extends Effect {
 
 	static {
 		Skript.registerEffect(EffExit.class,
@@ -60,15 +55,15 @@ public class EffExit extends Effect { // TODO [code style] warn user about code
 				"(exit|stop) <\\d+> (section|1:loop|2:conditional)s",
 				"(exit|stop) all (section|1:loop|2:conditional)s");
 	}
-	
+
 	private int breakLevels;
-	
+
 	private static final int EVERYTHING = 0;
 	private static final int LOOPS = 1;
 	private static final int CONDITIONALS = 2;
 	private static final String[] names = {"sections", "loops", "conditionals"};
 	private int type;
-	
+
 	@Override
 	public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelayed, ParseResult parser) {
 		switch (matchedPattern) {
@@ -99,7 +94,7 @@ public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelaye
 		}
 		return true;
 	}
-	
+
 	private static int numLevels(int type) {
 		List<TriggerSection> currentSections = ParserInstance.get().getCurrentSections();
 		if (type == EVERYTHING)
@@ -111,7 +106,7 @@ private static int numLevels(int type) {
 		}
 		return level;
 	}
-	
+
 	@Override
 	@Nullable
 	protected TriggerItem walk(Event event) {
@@ -131,15 +126,20 @@ protected TriggerItem walk(Event event) {
 		}
 		return node instanceof LoopSection ? ((LoopSection) node).getActualNext() : node.getNext();
 	}
-	
+
 	@Override
 	protected void execute(Event event) {
 		assert false;
 	}
-
+
+	@Override
+	public @Nullable ExecutionIntent executionIntent() {
+		return ExecutionIntent.stopSections(breakLevels);
+	}
+
 	@Override
 	public String toString(@Nullable Event event, boolean debug) {
 		return "stop " + breakLevels + " " + names[type];
 	}
-	
+
 }

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

@@ -23,14 +23,9 @@
 import ch.njol.skript.doc.Examples;
 import ch.njol.skript.doc.Name;
 import ch.njol.skript.doc.Since;
-import ch.njol.skript.lang.Effect;
-import ch.njol.skript.lang.Expression;
-import ch.njol.skript.lang.ReturnHandler;
+import ch.njol.skript.lang.*;
 import ch.njol.skript.lang.ReturnHandler.ReturnHandlerStack;
-import ch.njol.skript.lang.SectionExitHandler;
 import ch.njol.skript.lang.SkriptParser.ParseResult;
-import ch.njol.skript.lang.TriggerItem;
-import ch.njol.skript.lang.TriggerSection;
 import ch.njol.skript.lang.parser.ParserInstance;
 import ch.njol.skript.log.RetainingLogHandler;
 import ch.njol.skript.log.SkriptLogger;
@@ -130,6 +125,11 @@ protected void execute(Event event) {
 		assert false;
 	}
 
+	@Override
+	public ExecutionIntent executionIntent() {
+		return ExecutionIntent.stopTrigger();
+	}
+
 	@Override
 	public String toString(@Nullable Event event, boolean debug) {
 		return "return " + value.toString(event, debug);

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

@@ -29,6 +29,7 @@
 import ch.njol.util.Kleenean;
 import org.bukkit.event.Event;
 import org.eclipse.jdt.annotation.Nullable;
+import org.jetbrains.annotations.UnknownNullability;
 import org.skriptlang.skript.lang.script.ScriptWarning;
 
 @Name("Locally Suppress Warning")
@@ -41,13 +42,17 @@
 public class EffSuppressWarnings extends Effect {
 
 	static {
-		Skript.registerEffect(EffSuppressWarnings.class,
-			"[local[ly]] suppress [the] (1:conflict|2:variable save|3:[missing] conjunction[s]|4:starting [with] expression[s]|5:deprecated syntax) warning[s]"
-		);
+		StringBuilder warnings = new StringBuilder();
+		ScriptWarning[] values = ScriptWarning.values();
+		for (int i = 0; i < values.length; i++) {
+			if (i != 0)
+				warnings.append('|');
+			warnings.append(values[i].ordinal()).append(':').append(values[i].getPattern());
+		}
+		Skript.registerEffect(EffSuppressWarnings.class, "[local[ly]] suppress [the] (" + warnings + ") warning[s]");
 	}
 
-	private static final int CONFLICT = 1, INSTANCE = 2, CONJUNCTION = 3, START_EXPR = 4, DEPRECATED = 5;
-	private int mark = 0;
+	private @UnknownNullability ScriptWarning warning;
 
 	@Override
 	public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelayed, SkriptParser.ParseResult parseResult) {
@@ -56,11 +61,11 @@ public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelaye
 			return false;
 		}
 
-		mark = parseResult.mark;
-		if (mark == 1) {
-			Skript.warning("Variable conflict warnings no longer need suppression, as they have been removed altogether");
+		warning = ScriptWarning.values()[parseResult.mark];
+		if (warning.isDeprecated()) {
+			Skript.warning(warning.getDeprecationMessage());
 		} else {
-			getParser().getCurrentScript().suppressWarning(ScriptWarning.values()[mark - 2]);
+			getParser().getCurrentScript().suppressWarning(warning);
 		}
 		return true;
 	}
@@ -70,27 +75,7 @@ protected void execute(Event event) { }
 
 	@Override
 	public String toString(@Nullable Event event, boolean debug) {
-		String word;
-		switch (mark) {
-			case CONFLICT:
-				word = "conflict";
-				break;
-			case INSTANCE:
-				word = "variable save";
-				break;
-			case CONJUNCTION:
-				word = "missing conjunction";
-				break;
-			case START_EXPR:
-				word = "starting expression";
-				break;
-			case DEPRECATED:
-				word = "deprecated syntax";
-				break;
-			default:
-				throw new IllegalStateException();
-		}
-		return "suppress " + word + " warnings";
+		return "suppress " + warning.getWarningName() + " warnings";
 	}
 
 }

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

@@ -0,0 +1,69 @@
+package ch.njol.skript.lang;
+
+import com.google.common.base.Preconditions;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * Used to describe the intention of a {@link TriggerItem}.
+ * Currently only used to tell whether the item halts the execution or not and print the appropriate warnings.
+ * 
+ * @see TriggerItem#executionIntent() 
+ */
+public sealed interface ExecutionIntent extends Comparable<ExecutionIntent>
+	permits ExecutionIntent.StopTrigger, ExecutionIntent.StopSections {
+
+	static StopTrigger stopTrigger() {
+		return new StopTrigger();
+	}
+
+	static StopSections stopSections(int levels) {
+		Preconditions.checkArgument(levels > 0, "Depth must be at least 1");
+		return new StopSections(levels);
+	}
+
+	static StopSections stopSection() {
+		return new StopSections(1); 
+	}
+
+	@Nullable ExecutionIntent use();
+
+	final class StopTrigger implements ExecutionIntent {
+
+		private StopTrigger() {}
+
+		@Override
+		public StopTrigger use() {
+			return new StopTrigger();
+		}
+
+		@Override
+		@SuppressWarnings("ComparatorMethodParameterNotUsed")
+		public int compareTo(@NotNull ExecutionIntent other) {
+			return other instanceof StopTrigger ? 0 : 1;
+		}
+
+		@Override
+		public String toString() {
+			return "StopTrigger";
+		}
+
+	}
+
+	record StopSections(int levels) implements ExecutionIntent {
+
+		public @Nullable ExecutionIntent.StopSections use() {
+			return levels > 1 ? new StopSections(levels - 1) : null;
+		}
+
+		@Override
+		public int compareTo(@NotNull ExecutionIntent other) {
+			if (other instanceof StopTrigger)
+				return -1;
+			int levels = ((StopSections) other).levels;
+			return Integer.compare(this.levels, levels);
+		}
+
+	}
+
+}

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

@@ -28,13 +28,10 @@
 import ch.njol.util.coll.CollectionUtils;
 import org.bukkit.event.Event;
 import org.jetbrains.annotations.Nullable;
+import org.jetbrains.annotations.Unmodifiable;
 
 import java.lang.reflect.Array;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Iterator;
-import java.util.List;
-import java.util.NoSuchElementException;
+import java.util.*;
 
 /**
  * A list of expressions.
@@ -302,6 +299,23 @@ public Expression<? extends T>[] getExpressions() {
 		return expressions;
 	}
 
+	/**
+	 * Retrieves all expressions, including those nested within any {@code ExpressionList}s.
+	 *
+	 * @return A list of all expressions.
+	 */
+	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());
+				continue;
+			}
+			expressions.add(expression);
+		}
+		return expressions;
+	}
+
 	@Override
 	@SuppressWarnings("unchecked")
 	public Expression<T> simplify() {