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"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = checkDuplicatedNodes;
// https://github.com/babel/babel/blob/d383659ca6adec54b6054f77cdaa16da88e8a171/packages/babel-helper-transform-fixture-test-runner/src/index.js#L128

function checkDuplicatedNodes(babel, ast) {
  const nodes = new WeakSet();
  const parents = new WeakMap();
  const setParent = (child, parent) => {
    if (typeof child === 'object' && child !== null) {
      let p = parents.get(child);
      if (!p) {
        p = [];
        parents.set(child, p);
      }
      p.unshift(parent);
    }
  };
  const registerChildren = node => {
    for (const key in node) {
      if (Array.isArray(node[key])) {
        node[key].forEach(child => setParent(child, node));
      } else {
        setParent(node[key], node);
      }
    }
  };
  const hidePrivateProperties = (key, val) => {
    // Hides properties like _shadowedFunctionLiteral,
    // which makes the AST circular
    if (key[0] === '_') return '[Private]';
    return val;
  };
  babel.types.traverseFast(ast, node => {
    registerChildren(node);
    if (nodes.has(node)) {
      throw new Error('Do not reuse nodes. Use `t.cloneNode` (or `t.clone`/`t.cloneDeep` if using babel@6) to copy them.\n' + JSON.stringify(node, hidePrivateProperties, 2) + '\nParent:\n' + JSON.stringify(parents.get(node), hidePrivateProperties, 2));
    }
    nodes.add(node);
  });
}