Resolve WildcardType in GenericTypeResolver.resolveType()

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

@@ -193,6 +193,9 @@ else if (genericType instanceof ParameterizedType parameterizedType) {
 						else if (typeArgument instanceof ParameterizedType) {
 							generics[i] = ResolvableType.forType(resolveType(typeArgument, contextClass));
 						}
+						else if (typeArgument instanceof WildcardType) {
+							generics[i] = ResolvableType.forType(resolveType(typeArgument, contextClass));
+						}
 						else {
 							generics[i] = ResolvableType.forType(typeArgument);
 						}
@@ -203,6 +206,12 @@ else if (typeArgument instanceof ParameterizedType) {
 					}
 				}
 			}
+			else if (genericType instanceof WildcardType wildcardType) {
+				Type[] upperBounds = wildcardType.getUpperBounds();
+				if (upperBounds.length == 1) {
+					return resolveType(upperBounds[0], contextClass);
+				}
+			}
 		}
 		return genericType;
 	}

spring-core/src/test/java/org/springframework/core/GenericTypeResolverTests.java

@@ -260,6 +260,16 @@ void resolveTypeFromNestedParameterizedType() {
 		assertThat(resolvedType).isEqualTo(method(MyOptionalInterfaceType.class, "get").getGenericReturnType());
 	}
 
+	@Test
+	void resolveWildcardTypeArgument() {
+		Type genericReturnType = method(WildcardService.class, "findAll").getGenericReturnType();
+		Type resolvedType = resolveType(genericReturnType, PersonWildcardService.class);
+		assertThat(resolvedType).isInstanceOf(ParameterizedType.class);
+		ParameterizedType parameterizedType = (ParameterizedType) resolvedType;
+		assertThat(parameterizedType.getRawType()).isEqualTo(List.class);
+		assertThat(parameterizedType.getActualTypeArguments()[0]).isEqualTo(String.class);
+	}
+
 	private static Method method(Class<?> target, String methodName, Class<?>... parameterTypes) {
 		Method method = findMethod(target, methodName, parameterTypes);
 		assertThat(method).describedAs(target.getName() + "#" + methodName).isNotNull();
@@ -504,4 +514,17 @@ static class ConcreteType implements InterfaceWithDefaultMethod.AbstractType {
 		}
 	}
 
+	interface WildcardService<T> {
+
+		List<? extends T> findAll();
+	}
+
+	static class PersonWildcardService implements WildcardService<String> {
+
+		@Override
+		public List<? extends String> findAll() {
+			return List.of();
+		}
+	}
+
 }