Add createAssert(ValueProvider) to AssertFactory

assertj-core/src/main/java/org/assertj/core/api/AbstractAssert.java

@@ -478,7 +478,7 @@ public SELF satisfies(Condition<? super ACTUAL> condition) {
   @CheckReturnValue
   public <ASSERT extends AbstractAssert<?, ?>> ASSERT asInstanceOf(InstanceOfAssertFactory<?, ASSERT> instanceOfAssertFactory) {
     requireNonNull(instanceOfAssertFactory, shouldNotBeNull("instanceOfAssertFactory")::create);
-    objects.assertIsInstanceOf(info, actual, instanceOfAssertFactory.getType());
+    objects.assertIsInstanceOf(info, actual, instanceOfAssertFactory.getRawClass());
     return (ASSERT) instanceOfAssertFactory.createAssert(actual).withAssertionState(myself);
   }
 

assertj-core/src/main/java/org/assertj/core/api/AssertFactory.java

@@ -12,9 +12,13 @@
  */
 package org.assertj.core.api;
 
+import java.lang.reflect.Type;
+import java.util.Optional;
+
 /**
- * A single method factory interface to create an {@link Assert} for a given value.
- * This factory method typically wraps a call to <code>assertThat(actual)</code>
+ * A functional interface to create an {@link Assert} for a given value.
+ * <p>
+ * The factory typically wraps a call to <code>assertThat(actual)</code>
  * to produce a concrete assert type {@code ASSERT} for the input element of type {@code T}.
  * <p>
  * This interface is typically used by navigation assertions on iterable types like {@link AbstractIterableAssert}
@@ -29,12 +33,28 @@
 public interface AssertFactory<T, ASSERT extends Assert<?, ?>> {
 
   /**
-   * Creates the custom {@link Assert} instance for the given element value.
+   * Create the custom {@link Assert} instance for the given element value.
    * <p>
    * Typically, this will just invoke <code>assertThat(actual)</code>
    * @param actual the input value for the {@code Assert} instance
    * @return returns the custom {@code Assert} instance for the given element value
    */
   ASSERT createAssert(T actual);
 
+  /**
+   * Return the {@link Type} of the input this factory expects, or an empty {@code Optional}
+   * if the information is not available.
+   * 
+   * @implSpec Overriding implementations providing a non-empty optional are required to
+   * return a {@code Type} instance consistent with the value of the factory type parameter {@link T}.
+   * 
+   * @implNote The default implementation always returns an empty {@code Optional}.
+   * 
+   * @return the expected type, or an empty {@code Optional} if the information is not available.
+   * @since 3.26.0
+   */
+  default Optional<Type> getType() {
+    return Optional.empty();
+  }
+
 }