Refine KotlinDetector#hasSerializableAnnotation

Refine KotlinDetector#hasSerializableAnnotation in order to detect
deeply nested generic types.

Closes gh-35960

spring-core/src/main/java/org/springframework/core/KotlinDetector.java

@@ -148,9 +148,8 @@ public abstract class KotlinDetector {
 		if (resolvedClass.isAnnotationPresent(KOTLIN_SERIALIZABLE)) {
 			return true;
 		}
-		@Nullable Class<?>[] resolvedGenerics = type.resolveGenerics();
-		for (Class<?> resolvedGeneric : resolvedGenerics) {
-			if (resolvedGeneric != null && resolvedGeneric.isAnnotationPresent(KOTLIN_SERIALIZABLE)) {
+		for (ResolvableType genericType : type.getGenerics()) {
+			if (hasSerializableAnnotation(genericType)) {
 				return true;
 			}
 		}

spring-core/src/test/kotlin/org/springframework/core/KotlinDetectorTests.kt

@@ -57,6 +57,13 @@ class KotlinDetectorTests {
 
 		Assertions.assertThat(KotlinDetector.hasSerializableAnnotation(ResolvableType.forClassWithGenerics(Map::class.java, String::class.java, WithoutSerializable::class.java))).isFalse()
 		Assertions.assertThat(KotlinDetector.hasSerializableAnnotation(ResolvableType.forClassWithGenerics(Map::class.java, String::class.java, WithSerializable::class.java))).isTrue()
+		Assertions.assertThat(KotlinDetector.hasSerializableAnnotation(
+			ResolvableType.forClassWithGenerics(Map::class.java,
+				ResolvableType.forClass(String::class.java),
+				ResolvableType.forClassWithGenerics(List::class.java, WithSerializable::class.java)))).isTrue()
+		Assertions.assertThat(KotlinDetector.hasSerializableAnnotation(
+			ResolvableType.forClassWithGenerics(List::class.java,
+			ResolvableType.forClassWithGenerics(List::class.java, WithSerializable::class.java)))).isTrue()
 
 		Assertions.assertThat(KotlinDetector.hasSerializableAnnotation(ResolvableType.NONE)).isFalse()
 	}