Kotlin generic issue, should be subtype of Nothing - kotlin

Question

I'm writing a simple Spring test on Kotlin and have a compilation error with generics that I can't understand. The function is below:
#Test
fun actuatorRootReturnsOnlyAllowed() {
val expectBody:WebTestClient.BodySpec<Map<String, Map<String, Any>>, *> = client!!.get().uri("/app")
.accept(MediaType.APPLICATION_JSON_UTF8)
.exchange()
.expectStatus().isOk
.expectBody(object : ParameterizedTypeReference<Map<String, Map<String, Any>>>() {})
expectBody.consumeWith<Map<String, Map<String, Any>>> { result->
val actuatorLinks = result.responseBody!!["_links"]
Assert.assertTrue(actuatorLinks!!.containsKey("self"))
Assert.assertTrue(actuatorLinks.containsKey("health"))
Assert.assertTrue(actuatorLinks.containsKey("info"))
Assert.assertTrue(actuatorLinks.containsKey("loggers"))
Assert.assertTrue(actuatorLinks.containsKey("loggers-name"))
}
}
The problem is in line expectBody.consumeWith. For some reason Kotlin expects type Nothing with the compilation error: Error:(53, 32) Kotlin: Type argument is not within its bounds: should be subtype of 'Nothing!'.
Actual type of consumeWith method is EntityExchangeResult<T>, however method still expects Nothing. I would expect something like expectBody.consumeWithEntityExchangeResult<<Map<String, Map<String, Any>>>> or expectBody.consumeWith<Map<String, Map<String, Any>>> instead.
However with type Nothing I get the NullPointerException:
java.lang.NullPointerException
at com.example.ActuatorEndpointsTest.actuatorRootReturnsOnlyAllowed(ActuatorEndpointsTest.kt:52)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.springframework.test.context.junit4.statements.RunBeforeTestExecutionCallbacks.evaluate(RunBeforeTestExecutionCallbacks.java:73)
at org.springframework.test.context.junit4.statements.RunAfterTestExecutionCallbacks.evaluate(RunAfterTestExecutionCallbacks.java:83)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:251)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
Below is the same working equivalent in Java:
#Test
public void actuatorRootReturnsOnlyAllowed() {
client.get().uri("/app")
.accept(MediaType.APPLICATION_JSON_UTF8)
.exchange()
.expectStatus().isOk()
.expectBody(new ParameterizedTypeReference<Map<String, Map<String, Object>>>(){})
.consumeWith(result -> {
final Map<String, Object> actuatorLinks = result.getResponseBody().get("_links");
assertTrue(actuatorLinks.containsKey("self"));
assertTrue(actuatorLinks.containsKey("health"));
assertTrue(actuatorLinks.containsKey("info"));
assertTrue(actuatorLinks.containsKey("loggers"));
assertTrue(actuatorLinks.containsKey("loggers-name"));
});
}
Can anyone explain the reason why Kotlin expects Nothing and how this code can be corrected?