diff --git a/extensions/qute/deployment/src/main/java/io/quarkus/qute/deployment/Types.java b/extensions/qute/deployment/src/main/java/io/quarkus/qute/deployment/Types.java
index c428c2a7e7c3d..722ec3220809d 100644
--- a/extensions/qute/deployment/src/main/java/io/quarkus/qute/deployment/Types.java
+++ b/extensions/qute/deployment/src/main/java/io/quarkus/qute/deployment/Types.java
@@ -133,10 +133,13 @@ static boolean containsTypeVariable(Type type) {
     }
 
     static boolean isAssignableFrom(Type type1, Type type2, IndexView index, Map<DotName, AssignableInfo> assignableCache) {
-        // TODO consider type params in assignability rules
-        if (type1.kind() == Kind.ARRAY && type2.kind() == Kind.ARRAY) {
-            return isAssignableFrom(type1.asArrayType().component(), type2.asArrayType().component(), index, assignableCache);
+        if (type1.kind() == Kind.ARRAY) {
+            return type2.kind() == Kind.ARRAY
+                    ? isAssignableFrom(type1.asArrayType().component(), type2.asArrayType().component(), index,
+                            assignableCache)
+                    : false;
         }
+
         return Types.isAssignableFrom(box(type1).name(), box(type2).name(), index, assignableCache);
     }
 
@@ -166,6 +169,9 @@ private static Set<DotName> toNames(Collection<ClassInfo> classes) {
         }
 
         boolean isAssignableFrom(DotName clazz) {
+            if (clazz == null) {
+                return false;
+            }
             if (subclasses != null && subclasses.contains(clazz)) {
                 return true;
             }
@@ -188,6 +194,10 @@ static boolean isAssignableFrom(DotName className1, DotName className2, IndexVie
             return true;
         }
         ClassInfo class1 = index.getClassByName(className1);
+        if (class1 == null) {
+            // Not found in the index
+            return false;
+        }
         AssignableInfo assignableInfo = assignableCache.get(className1);
         if (assignableInfo == null) {
             // No cached info
diff --git a/extensions/qute/deployment/src/test/java/io/quarkus/qute/deployment/TypesTest.java b/extensions/qute/deployment/src/test/java/io/quarkus/qute/deployment/TypesTest.java
new file mode 100644
index 0000000000000..d6335613108d2
--- /dev/null
+++ b/extensions/qute/deployment/src/test/java/io/quarkus/qute/deployment/TypesTest.java
@@ -0,0 +1,75 @@
+package io.quarkus.qute.deployment;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.Serializable;
+import java.math.BigDecimal;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.jboss.jandex.ArrayType;
+import org.jboss.jandex.ClassType;
+import org.jboss.jandex.DotName;
+import org.jboss.jandex.Index;
+import org.jboss.jandex.Indexer;
+import org.jboss.jandex.PrimitiveType;
+import org.jboss.jandex.PrimitiveType.Primitive;
+import org.jboss.jandex.Type;
+import org.junit.jupiter.api.Test;
+
+import io.quarkus.qute.deployment.Types.AssignableInfo;
+
+public class TypesTest {
+
+    @Test
+    public void testIsAssignableFrom() throws IOException {
+        Index index = index(String.class, CharSequence.class, BigDecimal.class, Number.class, Serializable.class, Boolean.class,
+                Double.class);
+
+        ClassType stringType = ClassType.create(DotName.createSimple(String.class));
+        ClassType charSequenceType = ClassType.create(DotName.createSimple(CharSequence.class));
+        ClassType bigDecimalType = ClassType.create(DotName.createSimple(BigDecimal.class));
+        ClassType serializableType = ClassType.create(DotName.createSimple(Serializable.class));
+        ClassType numberType = ClassType.create(DotName.createSimple(Number.class));
+        Type booleanType = Types.box(Primitive.BOOLEAN);
+        ArrayType byteArrayType = ArrayType.create(PrimitiveType.BYTE, 1);
+        ArrayType intArrayType = ArrayType.create(PrimitiveType.INT, 1);
+        Map<DotName, AssignableInfo> cache = new HashMap<>();
+
+        // byte[] is not assignable from String
+        assertFalse(Types.isAssignableFrom(byteArrayType, stringType, index, cache));
+        // CharSequence is assignable from String
+        assertTrue(Types.isAssignableFrom(charSequenceType, stringType, index, cache));
+        // String is not assignable from CharSequence
+        assertFalse(Types.isAssignableFrom(stringType, charSequenceType, index, cache));
+        // String is not assignable from byte[]
+        assertFalse(Types.isAssignableFrom(stringType, byteArrayType, index, cache));
+        // Object is assignable from any type
+        assertTrue(Types.isAssignableFrom(ClassType.OBJECT_TYPE, stringType, index, cache));
+        // boolean is assignable from Boolean
+        assertTrue(Types.isAssignableFrom(PrimitiveType.BOOLEAN, booleanType, index, cache));
+        // boolean is not assignable from double
+        assertFalse(Types.isAssignableFrom(PrimitiveType.BOOLEAN, PrimitiveType.DOUBLE, index, cache));
+        // Serializable is assignable from BigDecimal
+        assertTrue(Types.isAssignableFrom(serializableType, bigDecimalType, index, cache));
+        // Number is assignable from BigDecimal
+        assertTrue(Types.isAssignableFrom(numberType, bigDecimalType, index, cache));
+        // byte[] is not assignable from int[]
+        assertFalse(Types.isAssignableFrom(byteArrayType, intArrayType, index, cache));
+    }
+
+    private static Index index(Class<?>... classes) throws IOException {
+        Indexer indexer = new Indexer();
+        for (Class<?> clazz : classes) {
+            try (InputStream stream = TypesTest.class.getClassLoader()
+                    .getResourceAsStream(clazz.getName().replace('.', '/') + ".class")) {
+                indexer.index(stream);
+            }
+        }
+        return indexer.complete();
+    }
+
+}