code: func (c *Comments) SetExpression(node Expression) {
  	// Skipping same node
  	if c.Current == node {
  		return
  	}
  	if c.Current != nil && c.Current.Idx1() == node.Idx1() {
  		c.Current = node
  		return
  	}
  	previous := c.Current
  	c.Current = node
  
  	// Apply the found comments and futures to the node and the previous.
  	c.applyComments(node, previous, TRAILING)
  }
docs: // SetExpression sets the current expression.
  // It is applied the found comments, unless the previous expression has not been unset.
  // It is skipped if the node is already set or if it is a part of the previous node.