Fix handling of value class with private constructor

See gh-32536

spring-web/src/main/java/org/springframework/web/method/support/InvocableHandlerMethod.java

@@ -319,7 +319,9 @@ public class InvocableHandlerMethod extends HandlerMethod {
 							KType type = parameter.getType();
 							if (!(type.isMarkedNullable() && arg == null) && type.getClassifier() instanceof KClass<?> kClass
 									&& KotlinDetector.isInlineClass(JvmClassMappingKt.getJavaClass(kClass))) {
-								arg = KClasses.getPrimaryConstructor(kClass).call(arg);
+								KFunction<?> valueClassConstructor = KClasses.getPrimaryConstructor(kClass);
+								KCallablesJvm.setAccessible(valueClassConstructor, true);
+								arg = valueClassConstructor.call(arg);
 							}
 							argMap.put(parameter, arg);
 						}

spring-web/src/test/kotlin/org/springframework/web/method/support/InvocableHandlerMethodKotlinTests.kt

@@ -112,6 +112,13 @@ class InvocableHandlerMethodKotlinTests {
 		Assertions.assertThat(value).isNull()
 	}
 
+	@Test
+	fun valueClassWithPrivateConstructor() {
+		composite.addResolver(StubArgumentResolver(Char::class.java, 'a'))
+		val value = getInvocable(ValueClassHandler::class.java, Char::class.java).invokeForRequest(request, null)
+		Assertions.assertThat(value).isEqualTo('a')
+	}
+
 	@Test
 	fun propertyAccessor() {
 		val value = getInvocable(PropertyAccessorHandler::class.java).invokeForRequest(request, null)
@@ -191,6 +198,8 @@ class InvocableHandlerMethodKotlinTests {
 		fun valueClassWithNullable(limit: LongValueClass?) =
 			limit?.value
 
+		fun valueClassWithPrivateConstructor(limit: ValueClassWithPrivateConstructor) =
+			limit.value
 	}
 
 	private class PropertyAccessorHandler {
@@ -238,6 +247,13 @@ class InvocableHandlerMethodKotlinTests {
 		}
 	}
 
+	@JvmInline
+	value class ValueClassWithPrivateConstructor private constructor(val value: Char) {
+		companion object {
+			fun from(value: Char) = ValueClassWithPrivateConstructor(value)
+		}
+	}
+
 	class CustomException(message: String) : Throwable(message)
 
 }