import type { Ast } from '../parser/types';
/**
 * Tree-shaking pass: remove unused let bindings from a bundled AST.
 *
 * Uses a mark-and-sweep (graph-based) algorithm:
 * 1. Build dependency graph: each let binding → names it references
 * 2. Find root: the last expression in the body (program output)
 * 3. Mark: BFS from root's references through the graph
 * 4. Sweep: remove unmarked Let nodes with side-effect-free values
 */
export declare function treeShake(ast: Ast): Ast;