code: @SuppressWarnings("deprecation")
  	public final void setValidatedNodeType(SqlNode node, RelDataType type) {
  		Objects.requireNonNull(type);
  		Objects.requireNonNull(node);
  		if (type.equals(unknownType)) {
  			// don't set anything until we know what it is, and don't overwrite
  			// a known type with the unknown type
  			return;
  		}
  		nodeToTypeMap.put(node, type);
  	}
docs: Saves the type of a {@link SqlNode}, now that it has been validated.
  
  <p>Unlike the base class method, this method is not deprecated.
  It is available from within Calcite, but is not part of the public API.
  
  @param node A SQL parse tree node, never null
  @param type Its type; must not be null