diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/result/AbstractHandlerResultHandler.java b/spring-webflux/src/main/java/org/springframework/web/reactive/result/HandlerResultHandlerSupport.java
similarity index 91%
rename from spring-webflux/src/main/java/org/springframework/web/reactive/result/AbstractHandlerResultHandler.java
rename to spring-webflux/src/main/java/org/springframework/web/reactive/result/HandlerResultHandlerSupport.java
index 9075733ebb..eac05c35d2 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/result/AbstractHandlerResultHandler.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/result/HandlerResultHandlerSupport.java
@@ -36,12 +36,13 @@ import org.springframework.web.server.ServerWebExchange;
 
 /**
  * Base class for {@link org.springframework.web.reactive.HandlerResultHandler
- * HandlerResultHandler} implementations that perform content negotiation.
+ * HandlerResultHandler} with support for content negotiation and access to a
+ * {@code ReactiveAdapter} registry.
  *
  * @author Rossen Stoyanchev
  * @since 5.0
  */
-public abstract class AbstractHandlerResultHandler implements Ordered {
+public abstract class HandlerResultHandlerSupport implements Ordered {
 
 	private static final MediaType MEDIA_TYPE_APPLICATION_ALL = new MediaType("application");
 
@@ -53,11 +54,11 @@ public abstract class AbstractHandlerResultHandler implements Ordered {
 	private int order = LOWEST_PRECEDENCE;
 
 
-	protected AbstractHandlerResultHandler(RequestedContentTypeResolver contentTypeResolver) {
+	protected HandlerResultHandlerSupport(RequestedContentTypeResolver contentTypeResolver) {
 		this(contentTypeResolver, new ReactiveAdapterRegistry());
 	}
 
-	protected AbstractHandlerResultHandler(RequestedContentTypeResolver contentTypeResolver,
+	protected HandlerResultHandlerSupport(RequestedContentTypeResolver contentTypeResolver,
 			ReactiveAdapterRegistry adapterRegistry) {
 
 		Assert.notNull(contentTypeResolver, "'contentTypeResolver' is required.");
@@ -74,14 +75,6 @@ public abstract class AbstractHandlerResultHandler implements Ordered {
 		return this.adapterRegistry;
 	}
 
-	/**
-	 * Shortcut to get a ReactiveAdapter for the top-level return value type.
-	 */
-	protected ReactiveAdapter getAdapter(HandlerResult result) {
-		Class<?> returnType = result.getReturnType().getRawClass();
-		return getAdapterRegistry().getAdapter(returnType, result.getReturnValue());
-	}
-
 	/**
 	 * Return the configured {@link RequestedContentTypeResolver}.
 	 */
@@ -105,6 +98,15 @@ public abstract class AbstractHandlerResultHandler implements Ordered {
 	}
 
 
+	/**
+	 * Get a {@code ReactiveAdapter} for the top-level return value type.
+	 * @return the matching adapter or {@code null}
+	 */
+	protected ReactiveAdapter getAdapter(HandlerResult result) {
+		Class<?> returnType = result.getReturnType().getRawClass();
+		return getAdapterRegistry().getAdapter(returnType, result.getReturnValue());
+	}
+
 	/**
 	 * Select the best media type for the current request through a content
 	 * negotiation algorithm.
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/AbstractMessageWriterResultHandler.java b/spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/AbstractMessageWriterResultHandler.java
index 5017f0f901..74bab5f0d2 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/AbstractMessageWriterResultHandler.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/AbstractMessageWriterResultHandler.java
@@ -33,7 +33,7 @@ import org.springframework.http.server.reactive.ServerHttpRequest;
 import org.springframework.http.server.reactive.ServerHttpResponse;
 import org.springframework.util.Assert;
 import org.springframework.web.reactive.accept.RequestedContentTypeResolver;
-import org.springframework.web.reactive.result.AbstractHandlerResultHandler;
+import org.springframework.web.reactive.result.HandlerResultHandlerSupport;
 import org.springframework.web.server.NotAcceptableStatusException;
 import org.springframework.web.server.ServerWebExchange;
 
@@ -44,7 +44,7 @@ import org.springframework.web.server.ServerWebExchange;
  * @author Rossen Stoyanchev
  * @since 5.0
  */
-public abstract class AbstractMessageWriterResultHandler extends AbstractHandlerResultHandler {
+public abstract class AbstractMessageWriterResultHandler extends HandlerResultHandlerSupport {
 
 	private final List<HttpMessageWriter<?>> messageWriters;
 
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/ModelAttributeMethodArgumentResolver.java b/spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/ModelAttributeMethodArgumentResolver.java
index d482f691b0..a4e21ae043 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/ModelAttributeMethodArgumentResolver.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/ModelAttributeMethodArgumentResolver.java
@@ -110,7 +110,7 @@ public class ModelAttributeMethodArgumentResolver implements HandlerMethodArgume
 				if (adapter.isNoValue() || adapter.isMultiValue()) {
 					return false;
 				}
-				clazz = ResolvableType.forMethodParameter(parameter).getGeneric(0).getRawClass();
+				clazz = parameter.nested().getNestedParameterType();
 			}
 			return !BeanUtils.isSimpleProperty(clazz);
 		}
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/result/view/ViewResolutionResultHandler.java b/spring-webflux/src/main/java/org/springframework/web/reactive/result/view/ViewResolutionResultHandler.java
index 103247e4e5..51d53bed68 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/result/view/ViewResolutionResultHandler.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/result/view/ViewResolutionResultHandler.java
@@ -46,7 +46,7 @@ import org.springframework.web.reactive.BindingContext;
 import org.springframework.web.reactive.HandlerResult;
 import org.springframework.web.reactive.HandlerResultHandler;
 import org.springframework.web.reactive.accept.RequestedContentTypeResolver;
-import org.springframework.web.reactive.result.AbstractHandlerResultHandler;
+import org.springframework.web.reactive.result.HandlerResultHandlerSupport;
 import org.springframework.web.server.NotAcceptableStatusException;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.support.HttpRequestPathHelper;
@@ -77,7 +77,7 @@ import org.springframework.web.server.support.HttpRequestPathHelper;
  * @author Rossen Stoyanchev
  * @since 5.0
  */
-public class ViewResolutionResultHandler extends AbstractHandlerResultHandler
+public class ViewResolutionResultHandler extends HandlerResultHandlerSupport
 		implements HandlerResultHandler, Ordered {
 
 	private static final Object NO_VALUE = new Object();
diff --git a/spring-webflux/src/test/java/org/springframework/web/reactive/result/HandlerResultHandlerTests.java b/spring-webflux/src/test/java/org/springframework/web/reactive/result/HandlerResultHandlerTests.java
index 63b45ec893..575aae9239 100644
--- a/spring-webflux/src/test/java/org/springframework/web/reactive/result/HandlerResultHandlerTests.java
+++ b/spring-webflux/src/test/java/org/springframework/web/reactive/result/HandlerResultHandlerTests.java
@@ -37,7 +37,7 @@ import static org.junit.Assert.*;
 import static org.springframework.http.MediaType.*;
 
 /**
- * Unit tests for {@link AbstractHandlerResultHandler}.
+ * Unit tests for {@link HandlerResultHandlerSupport}.
  * @author Rossen Stoyanchev
  */
 public class HandlerResultHandlerTests {
@@ -112,7 +112,7 @@ public class HandlerResultHandlerTests {
 
 
 	@SuppressWarnings("WeakerAccess")
-	private static class TestResultHandler extends AbstractHandlerResultHandler {
+	private static class TestResultHandler extends HandlerResultHandlerSupport {
 
 		protected TestResultHandler() {
 			this(new HeaderContentTypeResolver());