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.
expect(grandchild.tagName).toBe('DIV');
            expect(grandchild.childNodes.length).toBe(0);
          }
        }
      });
      itRenders('a div with a child', async render => {
        const e = await render(
          <div id="parent">
            <div id="child" />
          </div>,
        );
        expect(e.id).toBe('parent');
        expect(e.childNodes.length).toBe(1);
        expect(e.childNodes[0].id).toBe('child');
        expect(e.childNodes[0].childNodes.length).toBe(0);
      });
      itRenders('a div with multiple children', async render => {
        const e = await render(
          <div id="parent">
            <div id="child1" />
            <div id="child2" />
          </div>,
        );
        expect(e.id).toBe('parent');
        expect(e.childNodes.length).toBe(2);
        expect(e.childNodes[0].id).toBe('child1');
        expect(e.childNodes[0].childNodes.length).toBe(0);
        expect(e.childNodes[1].id).toBe('child2');
        expect(e.childNodes[1].childNodes.length).toBe(0);
      });