Fix ExprArithmetic Type Resolutions

src/main/java/ch/njol/skript/expressions/arithmetic/ExprArithmetic.java

@@ -164,31 +164,29 @@ public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelaye
 			} else { // first needs converting
 				// attempt to convert <first> to types that make valid operations with <second>
 				Class<?> secondClass = second.getReturnType();
-				Class[] leftTypes = Arithmetics.getOperations(operator).stream()
-					.filter(info -> info.getRight().isAssignableFrom(secondClass))
-					.map(OperationInfo::getLeft)
-					.toArray(Class[]::new);
-				if (leftTypes.length == 0) { // no known operations with second's type
+				List<? extends OperationInfo<?, ?, ?>> operations = Arithmetics.lookupRightOperations(operator, secondClass);
+				if (operations.isEmpty()) { // no known operations with second's type
 					if (secondClass != Object.class) // there won't be any operations
 						return error(first.getReturnType(), secondClass);
 					first = (Expression<L>) first.getConvertedExpression(Object.class);
 				} else {
-					first = (Expression<L>) first.getConvertedExpression(leftTypes);
+					first = (Expression<L>) first.getConvertedExpression(operations.stream()
+							.map(OperationInfo::getLeft)
+							.toArray(Class[]::new));
 				}
 			}
 		} else if (second instanceof UnparsedLiteral) { // second needs converting
 			// attempt to convert <second> to types that make valid operations with <first>
 			Class<?> firstClass = first.getReturnType();
-			List<? extends OperationInfo<?, ?, ?>> operations = Arithmetics.getOperations(operator, firstClass);
+			List<? extends OperationInfo<?, ?, ?>> operations = Arithmetics.lookupLeftOperations(operator, firstClass);
 			if (operations.isEmpty()) { // no known operations with first's type
 				if (firstClass != Object.class) // there won't be any operations
 					return error(firstClass, second.getReturnType());
 				second = (Expression<R>) second.getConvertedExpression(Object.class);
 			} else {
 				second = (Expression<R>) second.getConvertedExpression(operations.stream()
 						.map(OperationInfo::getRight)
-						.toArray(Class[]::new)
-				);
+						.toArray(Class[]::new));
 			}
 		}
 
@@ -223,14 +221,13 @@ public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelaye
 			Class<?>[] returnTypes = null;
 			if (!(firstClass == Object.class && secondClass == Object.class)) { // both aren't object
 				if (firstClass == Object.class) {
-					returnTypes = Arithmetics.getOperations(operator).stream()
-							.filter(info -> info.getRight().isAssignableFrom(secondClass))
+					returnTypes = Arithmetics.lookupRightOperations(operator, secondClass).stream()
 							.map(OperationInfo::getReturnType)
 							.toArray(Class[]::new);
 				} else { // secondClass is Object
-					returnTypes = Arithmetics.getOperations(operator, firstClass).stream()
-						.map(OperationInfo::getReturnType)
-						.toArray(Class[]::new);
+					returnTypes = Arithmetics.lookupLeftOperations(operator, firstClass).stream()
+							.map(OperationInfo::getReturnType)
+							.toArray(Class[]::new);
 				}
 			}
 			if (returnTypes == null) { // both are object; can't determine anything

src/main/java/org/skriptlang/skript/lang/arithmetic/Arithmetics.java

@@ -12,6 +12,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Collection;
+import java.util.Objects;
 import java.util.Set;
 import java.util.HashSet;
 import java.util.function.Supplier;
@@ -83,6 +84,47 @@ public static boolean operationExists(Operator operator, Class<?> leftClass, Cla
 			.collect(Collectors.toList());
 	}
 
+	/**
+	 * Returns all valid operations from {@code operator} and {@code leftClass}.
+	 * Unlike {@link #getOperations(Operator, Class)}, this method considers Converters.
+	 * @param operator The operator for the desired operations
+	 * @param leftClass Class representing the desired left-hand argument type
+	 * @return A list containing all valid operations from {@code operator} and {@code leftClass}.
+	 * @param <L> The type of the left-hand argument
+	 */
+	@SuppressWarnings({"unchecked", "rawtypes"})
+	public static <L> List<OperationInfo<L, ?, ?>> lookupLeftOperations(Operator operator, Class<L> leftClass) {
+		return (List) getOperations(operator).stream()
+			.map(info -> {
+				if (info.getLeft().isAssignableFrom(leftClass)) {
+					return info;
+				}
+				return info.getConverted(leftClass, info.getRight(), info.getReturnType());
+			})
+			.filter(Objects::nonNull)
+			.collect(Collectors.toList());
+	}
+
+	/**
+	 * Returns all valid operations from {@code operator} and {@code rightClass}.
+	 * @param operator The operator for the desired operations
+	 * @param rightClass Class representing the desired right-hand argument type
+	 * @return A list containing all valid operations from {@code operator} and {@code rightClass}.
+	 * @param <R> The type of the right-hand argument
+	 */
+	@SuppressWarnings({"unchecked", "rawtypes"})
+	public static <R> List<OperationInfo<?, R, ?>> lookupRightOperations(Operator operator, Class<R> rightClass) {
+		return (List) getOperations(operator).stream()
+			.map(info -> {
+				if (info.getRight().isAssignableFrom(rightClass)) {
+					return info;
+				}
+				return info.getConverted(info.getLeft(), rightClass, info.getReturnType());
+			})
+			.filter(Objects::nonNull)
+			.collect(Collectors.toList());
+	}
+
 	@Nullable
 	@SuppressWarnings("unchecked")
 	public static <L, R, T> OperationInfo<L, R, T> getOperationInfo(Operator operator, Class<L> leftClass, Class<R> rightClass, Class<T> returnType) {

src/test/skript/tests/syntaxes/expressions/ExprArithmetic.sk

@@ -278,3 +278,10 @@ test "arithmetic type switcheroo":
 	loop 2 times:
 		set {_x} to {_a} + {_b}
 		set {_b} to 5
+
+local function arithmetic_xp() returns experience:
+	return 5 xp
+
+test "arithmetic parse time conversion":
+	set {_x} to arithmetic_xp() + 5
+	assert {_x} is 10 with "failed to calculate experience + number"