import * as ast from "../ast";
/**
 * Returns the free locals and free functions of an expression. (The type system ensures these are
 * disjoint within any top-level declaration.)
 */
export declare function expressionFreeVars(exp: ast.Expression): Set<string>;
/**
 * Ensures that the free locals of an expression have been defined along every control path
 * Raises an error if there are potentially un-initialized stack locals
 *  - Precondition: the expression must have passed typechecking
 *  - Precondition: all the current stack locals must be in [locals]
 *  - Precondition: [defined] is the subset of [locals] defined on every
 *  - Returns the free functions (the free locals that are not stack-allocated locals)
 */
export declare function checkExpressionUsesGetFreeFunctions(locals: Set<string>, defined: Set<string>, exp: ast.Expression): Set<string>;
export declare function checkStatementFlow(locals: Set<string>, constants: Set<string>, defined: Set<string>, stm: ast.Statement): {
    locals: Set<string>;
    defined: Set<string>;
    functions: Set<string>;
    returns: boolean;
};