public static @NotNull LighterASTNode requiredChildOfType(@NotNull LighterAST tree, @NotNull LighterASTNode node, @NotNull IElementType type) {
    LighterASTNode child = firstChildOfType(tree, node, type);
    assert child != null : "Required child " + type + " not found in " + node.getTokenType() + ": " + tree.getChildren(node);
    return child;
  }
public static @NotNull LighterASTNode requiredChildOfType(@NotNull LighterAST tree, @NotNull LighterASTNode node, @NotNull IElementType type)