This DEV-only field was added in 836331ba5f69f2cc53b273ec073fae116db14302 by @sebmarkbage but it's not being used anymore to my knowledge.
workInProgress.alternate = null;
    
    workInProgress.flags |= Placement;
  }
  
  workInProgress.tag = ClassComponent;
  
  
  
  
  let hasContext;
  if (isLegacyContextProvider(Component)) {
    hasContext = true;
    pushLegacyContextProvider(workInProgress);
  } else {
    hasContext = false;
  }
  prepareToReadContext(workInProgress, renderLanes);
  constructClassInstance(workInProgress, Component, nextProps);
  mountClassInstance(workInProgress, Component, nextProps, renderLanes);
  return finishClassComponent(
    null,
    workInProgress,
    Component,
    true,
    hasContext,
    renderLanes,
  );
}
function mountIndeterminateComponent(