declare module '@glimmer/syntax/lib/utils' {
    import type * as ASTv1 from "@glimmer/syntax/lib/v1/api";
    import type * as HBS from "@glimmer/syntax/lib/v1/handlebars-ast";
    export function childrenFor(node: ASTv1.Block | ASTv1.Template | ASTv1.ElementNode): ASTv1.TopLevelStatement[];
    export function appendChild(
      parent: ASTv1.Block | ASTv1.Template | ASTv1.ElementNode,
      node: ASTv1.Statement
    ): void;
    export function isHBSLiteral(path: HBS.Expression): path is HBS.Literal;
    export function isHBSLiteral(path: ASTv1.Expression): path is ASTv1.Literal;
    export function printLiteral(literal: ASTv1.Literal): string;
    export function isUpperCase(tag: string): boolean;
    export function isLowerCase(tag: string): boolean;
}