normalizedName?: string;
  create(props?: { [prop: string]: any }): T;
}

export interface Owner {
  lookup<T>(fullName: string, options?: LookupOptions): T;
  lookup(fullName: string, options?: LookupOptions): any;
  factoryFor<T, C>(fullName: string, options?: LookupOptions): Factory<T, C> | undefined;
  factoryFor(fullName: string, options?: LookupOptions): Factory<any, any> | undefined;
  buildChildEngineInstance<T>(name: string): T;
  hasRegistration(name: string, options?: LookupOptions): boolean;
}

import { symbol } from '@ember/-internals/utils';

export const OWNER = symbol('OWNER');

/**
  Framework objects in an Ember application (components, services, routes, etc.)
  are created via a factory and dependency injection system. Each of these
  objects is the responsibility of an "owner", which handled its
  instantiation and manages its lifetime.

  `getOwner` fetches the owner object responsible for an instance. This can
  be used to lookup or resolve other class instances, or register new factories
  into the owner.

  For example, this component dynamically looks up a service based on the
  `audioType` passed as an attribute:

  ```app/components/play-audio.js

import { descriptorFor, Meta, peekMeta } from '@ember/-internals/meta';
import { symbol } from '@ember/-internals/utils';
import { DEBUG } from '@glimmer/env';
import changeEvent from './change_event';
import { sendEvent } from './events';
import ObserverSet from './observer_set';
import { markObjectAsDirty } from './tags';
import { assertNotRendered } from './transaction';

/**
 @module ember
 @private
 */

export const PROPERTY_DID_CHANGE = symbol('PROPERTY_DID_CHANGE');

const observerSet = new ObserverSet();
let deferred = 0;

/**
  This function is called just after an object property has changed.
  It will notify any observers and clear caches among other things.

  Normally you will not need to call this method directly but if for some
  reason you can't directly watch a property you can invoke this method
  manually.

  @method notifyPropertyChange
  @for @ember/object
  @param {Object} obj The object with the property that will change
  @param {String} keyName The property key (or path) that will change.

import {
  ActionSupport,
  ChildViewsSupport,
  ClassNamesSupport,
  CoreView,
  getViewElement,
  ViewMixin,
  ViewStateSupport,
} from '@ember/-internals/views';
import { assert } from '@ember/debug';
import { DirtyableTag } from '@glimmer/reference';
import { normalizeProperty, SVG_NAMESPACE } from '@glimmer/runtime';

import { RootReference, UPDATE } from './utils/references';

export const DIRTY_TAG = symbol('DIRTY_TAG');
export const ARGS = symbol('ARGS');
export const ROOT_REF = symbol('ROOT_REF');
export const IS_DISPATCHING_ATTRS = symbol('IS_DISPATCHING_ATTRS');
export const HAS_BLOCK = symbol('HAS_BLOCK');
export const BOUNDS = symbol('BOUNDS');

/**
@module @ember/component
*/

/**
  A `Component` is a view that is completely
  isolated. Properties accessed in its templates go
  to the view object and actions are targeted at
  the view object. There is no access to the

import { Meta, meta as metaFor } from '@ember/-internals/meta';
import { isProxy, setupMandatorySetter, symbol } from '@ember/-internals/utils';
import { EMBER_METAL_TRACKED_PROPERTIES } from '@ember/canary-features';
import { backburner } from '@ember/runloop';
import { DEBUG } from '@glimmer/env';
import {
  combine,
  CONSTANT_TAG,
  DirtyableTag,
  Tag,
  TagWrapper,
  UpdatableTag,
} from '@glimmer/reference';

export const UNKNOWN_PROPERTY_TAG = symbol('UNKNOWN_PROPERTY_TAG');

function makeTag(): TagWrapper<DirtyableTag> {
  return DirtyableTag.create();
}

export function tagForProperty(object: any, propertyKey: string | symbol, _meta?: Meta): Tag {
  let objectType = typeof object;
  if (objectType !== 'function' && (objectType !== 'object' || object === null)) {
    return CONSTANT_TAG;
  }
  let meta = _meta === undefined ? metaFor(object) : _meta;

  if (EMBER_METAL_TRACKED_PROPERTIES) {
    if (!(propertyKey in object) && typeof object[UNKNOWN_PROPERTY_TAG] === 'function') {
      return object[UNKNOWN_PROPERTY_TAG](propertyKey);
    }

  Tag,
  TagWrapper,
  UpdatableTag,
  VersionedPathReference,
  VersionedReference,
} from '@glimmer/reference';
import {
  CapturedArguments,
  ConditionalReference as GlimmerConditionalReference,
  PrimitiveReference,
} from '@glimmer/runtime';
import { Option, unreachable } from '@glimmer/util';
import { HelperFunction, HelperInstance, RECOMPUTE_TAG } from '../helper';
import emberToBool from './to-bool';

export const UPDATE = symbol('UPDATE');
export const INVOKE = symbol('INVOKE');
export const ACTION = symbol('ACTION');

let maybeFreeze: (obj: any) => void;
if (DEBUG) {
  // gaurding this in a DEBUG gaurd (as well as all invocations)
  // so that it is properly stripped during the minification's
  // dead code elimination
  maybeFreeze = (obj: any) => {
    // re-freezing an already frozen object introduces a significant
    // performance penalty on Chrome (tested through 59).
    //
    // See: https://bugs.chromium.org/p/v8/issues/detail?id=6450
    if (!Object.isFrozen(obj)) {
      Object.freeze(obj);

/**
@module @ember/object
*/
import { descriptorFor, isDescriptor, meta } from '@ember/-internals/meta';
import { HAS_NATIVE_PROXY, symbol, toString } from '@ember/-internals/utils';
import { EMBER_METAL_TRACKED_PROPERTIES } from '@ember/canary-features';
import { assert, deprecate } from '@ember/debug';
import { PROPERTY_BASED_DESCRIPTORS } from '@ember/deprecated-features';
import { DEBUG } from '@glimmer/env';
import { isPath } from './path_cache';
import { tagForProperty } from './tags';
import { getCurrentTracker } from './tracked';

export const PROXY_CONTENT = symbol('PROXY_CONTENT');

export let getPossibleMandatoryProxyValue: (obj: object, keyName: string) => any;

if (DEBUG && HAS_NATIVE_PROXY) {
  getPossibleMandatoryProxyValue = function getPossibleMandatoryProxyValue(obj, keyName) {
    let content = obj[PROXY_CONTENT];
    if (content === undefined) {
      return obj[keyName];
    } else {
      /* global Reflect */
      return Reflect.get(content, keyName, obj);
    }
  };
}

interface MaybeHasUnknownProperty {
  unknownProperty?: (keyName: string) => any;

    Increment count
  </button>
  ```

  You can also use the `value` option:

  ```handlebars
  <input value={{name}} oninput={{fn (mut name) value="target.value"}}>
  ```

  @method mut
  @param {Object} [attr] the "two-way" attribute that can be modified.
  @for Ember.Templates.helpers
  @public
*/
const MUT_REFERENCE = symbol('MUT');
const SOURCE = symbol('SOURCE');

export function isMut(ref: any): boolean {
  return ref && ref[MUT_REFERENCE];
}

export function unMut(ref: any) {
  return ref[SOURCE] || ref;
}

export default function(_vm: VM, args: Arguments) {
  let rawRef = args.positional.at(0);

  if (isMut(rawRef)) {
    return rawRef;

if (DEBUG) {
  counters = {
    peekCalls: 0,
    peekPrototypeWalks: 0,
    setCalls: 0,
    deleteCalls: 0,
    metaCalls: 0,
    metaInstantiated: 0,
  };
}

/**
@module ember
*/

export const UNDEFINED = symbol('undefined');

// FLAGS
const SOURCE_DESTROYING = 1 << 1;
const SOURCE_DESTROYED = 1 << 2;
const META_DESTROYED = 1 << 3;

export class Meta {
  _descriptors: any | undefined;
  _watching: any | undefined;
  _mixins: any | undefined;
  _deps: any | undefined;
  _chainWatchers: any | undefined;
  _chains: any | undefined;
  _tag: Tag | undefined;
  _tags: any | undefined;

    if (typeof value === 'function' && value[ACTION]) {
      attrs[name] = value;
    } else if (ref[UPDATE]) {
      attrs[name] = new MutableCell(ref, value);
    }

    args[name] = ref;
    props[name] = value;
  }

  props.attrs = attrs;

  return props;
}

const REF = symbol('REF');

class MutableCell {
  public value: any;
  constructor(ref: any, value: any) {
    this[MUTABLE_CELL] = true;
    this[REF] = ref;
    this.value = value;
  }

  update(val: any) {
    this[REF][UPDATE](val);
  }
}

  ```handlebars
  <ul>
  {{#each-in user as |key value|}}
    <li>{{key}}: {{value}}</li>
  {{/each-in}}
  </ul>
  ```

  Outputting their name and age.

  @method each-in
  @for Ember.Templates.helpers
  @public
  @since 2.1.0
*/
const EACH_IN_REFERENCE = symbol('EACH_IN');

class EachInReference implements VersionedPathReference {
  public tag: Tag;

  constructor(private inner: VersionedPathReference) {
    this.tag = inner.tag;
    this[EACH_IN_REFERENCE] = true;
  }

  value(): Opaque {
    return this.inner.value();
  }

  get(key: string): VersionedPathReference {
    return this.inner.get(key);