Follow up from https://github.com/facebook/react/pull/11616.

Here's one I found. These two invariants:

https://github.com/facebook/react/blob/7e7127387ba64f57299eaff8656542cea6fb3a2d/packages/react-reconciler/src/ReactFiberClassComponent.js#L330-L343

are in a function that's behind a DEV block:

https://github.com/facebook/react/blob/7e7127387ba64f57299eaff8656542cea6fb3a2d/packages/react-reconciler/src/ReactFiberClassComponent.js#L447-L449

I don't think this is intentional, but need to verify.

There may be more. I'll use this issue to track while https://github.com/facebook/react/pull/11616 preserves existing behavior.
workInProgress,
    instance,
    newProps,
    newContext,
  ) {
    startPhaseTimer(workInProgress, 'componentWillReceiveProps');
    const oldState = instance.state;
    instance.componentWillReceiveProps(newProps, newContext);
    stopPhaseTimer();
    
    if (debugRenderPhaseSideEffects) {
      instance.componentWillReceiveProps(newProps, newContext);
    }
    if (instance.state !== oldState) {
      if (__DEV__) {
        const componentName = getComponentName(workInProgress) || 'Component';
        if (!didWarnAboutStateAssignmentForComponent[componentName]) {
          warning(
            false,
            '%s.componentWillReceiveProps(): Assigning directly to ' +
              "this.state is deprecated (except inside a component's " +
              'constructor). Use setState instead.',
            componentName,
          );
          didWarnAboutStateAssignmentForComponent[componentName] = true;
        }
      }
      updater.enqueueReplaceState(instance, instance.state, null);
    }
  }