From 7cd4907a0242f6eb56e79f8289472d9b940a218a Mon Sep 17 00:00:00 2001
From: Dan Abramov <dan.abramov@gmail.com>
Date: Tue, 15 May 2018 18:30:48 +0100
Subject: [PATCH] Delete React Call/Return experiment

---
 packages/react-call-return/README.md          |  32 --
 packages/react-call-return/index.js           |  12 -
 packages/react-call-return/npm/index.js       |   7 -
 packages/react-call-return/package.json       |  19 -
 .../react-call-return/src/ReactCallReturn.js  |  95 -----
 .../ReactCallReturn-test.internal.js          | 326 ------------------
 .../ReactServerRendering-test.internal.js     |  21 --
 .../src/server/ReactPartialRenderer.js        |   9 -
 .../src/ReactDebugFiberPerf.js                |   4 -
 packages/react-reconciler/src/ReactFiber.js   |  10 -
 .../src/ReactFiberBeginWork.js                |  55 ---
 .../src/ReactFiberCommitWork.js               |   5 -
 .../src/ReactFiberCompleteWork.js             |  87 -----
 .../ReactIncrementalPerf-test.internal.js     |  49 ---
 ...ReactIncrementalPerf-test.internal.js.snap |  19 -
 .../react/src/__tests__/ReactChildren-test.js |  51 ---
 packages/shared/ReactSymbols.js               |   4 -
 packages/shared/ReactTypeOfWork.js            |   6 +-
 packages/shared/getComponentName.js           |   6 -
 scripts/rollup/bundles.js                     |  10 -
 20 files changed, 3 insertions(+), 824 deletions(-)
 delete mode 100644 packages/react-call-return/README.md
 delete mode 100644 packages/react-call-return/index.js
 delete mode 100644 packages/react-call-return/npm/index.js
 delete mode 100644 packages/react-call-return/package.json
 delete mode 100644 packages/react-call-return/src/ReactCallReturn.js
 delete mode 100644 packages/react-call-return/src/__tests__/ReactCallReturn-test.internal.js

diff --git a/packages/react-call-return/README.md b/packages/react-call-return/README.md
deleted file mode 100644
index 6cfd1265aabfe..0000000000000
--- a/packages/react-call-return/README.md
+++ /dev/null
@@ -1,32 +0,0 @@
-# react-call-return
-
-This is an experimental package for multi-pass rendering in React.
-
-**Its API is not as stable as that of React, React Native, or React DOM, and does not follow the common versioning scheme.**
-
-**Use it at your own risk.**
-
-# No, Really, It Is Unstable
-
-This is **an experiment**.
-
-We **will** replace this with a different API in the future.  
-It can break between patch versions of React.
-
-We also know that **it has bugs**.
-
-Don't rely on this for anything except experiments.  
-Even in experiments, make sure to lock the versions so that an update doesn't break your app.
-
-Don't publish third party components relying on this unless you clearly mark them as experimental too.  
-They will break.
-
-Have fun! Let us know if you find interesting use cases for it.
-
-# API
-
-See the test case in `src/__tests__/ReactCallReturn.js` for an example.
-
-# What and Why
-
-The API is not very intuitive right now, but [this is a good overview](https://cdb.reacttraining.com/react-call-return-what-and-why-7e7761f81843) of why it might be useful in some cases. We are very open to better API ideas for this concept.
diff --git a/packages/react-call-return/index.js b/packages/react-call-return/index.js
deleted file mode 100644
index 8d3798337c698..0000000000000
--- a/packages/react-call-return/index.js
+++ /dev/null
@@ -1,12 +0,0 @@
-/**
- * Copyright (c) 2013-present, Facebook, Inc.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- *
- * @flow
- */
-
-'use strict';
-
-module.exports = require('./src/ReactCallReturn');
diff --git a/packages/react-call-return/npm/index.js b/packages/react-call-return/npm/index.js
deleted file mode 100644
index 0856ded523d75..0000000000000
--- a/packages/react-call-return/npm/index.js
+++ /dev/null
@@ -1,7 +0,0 @@
-'use strict';
-
-if (process.env.NODE_ENV === 'production') {
-  module.exports = require('./cjs/react-call-return.production.min.js');
-} else {
-  module.exports = require('./cjs/react-call-return.development.js');
-}
diff --git a/packages/react-call-return/package.json b/packages/react-call-return/package.json
deleted file mode 100644
index 52256ef0f9478..0000000000000
--- a/packages/react-call-return/package.json
+++ /dev/null
@@ -1,19 +0,0 @@
-{
-  "name": "react-call-return",
-  "description": "Experimental APIs for multi-pass rendering in React.",
-  "version": "0.8.0",
-  "repository": "facebook/react",
-  "files": [
-    "LICENSE",
-    "README.md",
-    "index.js",
-    "cjs/"
-  ],
-  "dependencies": {
-    "fbjs": "^0.8.16",
-    "object-assign": "^4.1.1"
-  },
-  "peerDependencies": {
-    "react": "^16.0.0"
-  }
-}
diff --git a/packages/react-call-return/src/ReactCallReturn.js b/packages/react-call-return/src/ReactCallReturn.js
deleted file mode 100644
index 432ff8f192223..0000000000000
--- a/packages/react-call-return/src/ReactCallReturn.js
+++ /dev/null
@@ -1,95 +0,0 @@
-/**
- * Copyright (c) 2014-present, Facebook, Inc.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- *
- * @flow
- */
-
-import {
-  REACT_CALL_TYPE,
-  REACT_RETURN_TYPE,
-  REACT_ELEMENT_TYPE,
-} from 'shared/ReactSymbols';
-
-import type {ReactCall, ReactNodeList, ReactReturn} from 'shared/ReactTypes';
-
-type CallHandler<T, V> = (props: T, returns: Array<V>) => ReactNodeList;
-
-export function unstable_createCall<T, V>(
-  children: ReactNodeList,
-  handler: CallHandler<T, V>,
-  props: T,
-  key: ?string = null,
-): ReactCall<V> {
-  const call = {
-    // This tag allow us to uniquely identify this as a React Call
-    $$typeof: REACT_ELEMENT_TYPE,
-    type: REACT_CALL_TYPE,
-    key: key == null ? null : '' + key,
-    ref: null,
-    props: {
-      props,
-      handler,
-      children: children,
-    },
-  };
-
-  if (__DEV__) {
-    // TODO: Add _store property for marking this as validated.
-    if (Object.freeze) {
-      Object.freeze(call.props);
-      Object.freeze(call);
-    }
-  }
-
-  return call;
-}
-
-export function unstable_createReturn<V>(value: V): ReactReturn<V> {
-  const returnNode = {
-    // This tag allow us to uniquely identify this as a React Call
-    $$typeof: REACT_ELEMENT_TYPE,
-    type: REACT_RETURN_TYPE,
-    key: null,
-    ref: null,
-    props: {
-      value,
-    },
-  };
-
-  if (__DEV__) {
-    // TODO: Add _store property for marking this as validated.
-    if (Object.freeze) {
-      Object.freeze(returnNode);
-    }
-  }
-
-  return returnNode;
-}
-
-/**
- * Verifies the object is a call object.
- */
-export function unstable_isCall(object: mixed): boolean {
-  return (
-    typeof object === 'object' &&
-    object !== null &&
-    object.type === REACT_CALL_TYPE
-  );
-}
-
-/**
- * Verifies the object is a return object.
- */
-export function unstable_isReturn(object: mixed): boolean {
-  return (
-    typeof object === 'object' &&
-    object !== null &&
-    object.type === REACT_RETURN_TYPE
-  );
-}
-
-export const unstable_REACT_RETURN_TYPE = REACT_RETURN_TYPE;
-export const unstable_REACT_CALL_TYPE = REACT_CALL_TYPE;
diff --git a/packages/react-call-return/src/__tests__/ReactCallReturn-test.internal.js b/packages/react-call-return/src/__tests__/ReactCallReturn-test.internal.js
deleted file mode 100644
index 84018bac30b6f..0000000000000
--- a/packages/react-call-return/src/__tests__/ReactCallReturn-test.internal.js
+++ /dev/null
@@ -1,326 +0,0 @@
-/**
- * Copyright (c) 2013-present, Facebook, Inc.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- *
- * @emails react-core
- */
-
-'use strict';
-
-let React;
-let ReactFeatureFlags;
-let ReactNoop;
-let ReactCallReturn;
-
-describe('ReactCallReturn', () => {
-  beforeEach(() => {
-    jest.resetModules();
-    ReactFeatureFlags = require('shared/ReactFeatureFlags');
-    ReactFeatureFlags.debugRenderPhaseSideEffectsForStrictMode = false;
-    React = require('react');
-    ReactNoop = require('react-noop-renderer');
-    ReactCallReturn = require('react-call-return');
-  });
-
-  function div(...children) {
-    children = children.map(c => (typeof c === 'string' ? {text: c} : c));
-    return {type: 'div', children, prop: undefined};
-  }
-
-  function span(prop) {
-    return {type: 'span', children: [], prop};
-  }
-
-  it('should render a call', () => {
-    const ops = [];
-
-    function Continuation({isSame}) {
-      ops.push(['Continuation', isSame]);
-      return <span prop={isSame ? 'foo==bar' : 'foo!=bar'} />;
-    }
-
-    // An alternative API could mark Continuation as something that needs
-    // returning. E.g. Continuation.returnType = 123;
-    function Child({bar}) {
-      ops.push(['Child', bar]);
-      return ReactCallReturn.unstable_createReturn({
-        props: {
-          bar: bar,
-        },
-        continuation: Continuation,
-      });
-    }
-
-    function Indirection() {
-      ops.push('Indirection');
-      return [<Child key="a" bar={true} />, <Child key="b" bar={false} />];
-    }
-
-    function HandleReturns(props, returns) {
-      ops.push('HandleReturns');
-      return returns.map((y, i) => (
-        <y.continuation key={i} isSame={props.foo === y.props.bar} />
-      ));
-    }
-
-    // An alternative API could mark Parent as something that needs
-    // returning. E.g. Parent.handler = HandleReturns;
-    function Parent(props) {
-      ops.push('Parent');
-      return ReactCallReturn.unstable_createCall(
-        props.children,
-        HandleReturns,
-        props,
-      );
-    }
-
-    function App() {
-      return (
-        <div>
-          <Parent foo={true}>
-            <Indirection />
-          </Parent>
-        </div>
-      );
-    }
-
-    ReactNoop.render(<App />);
-    ReactNoop.flush();
-
-    expect(ops).toEqual([
-      'Parent',
-      'Indirection',
-      ['Child', true],
-      // Return
-      ['Child', false],
-      // Return
-      'HandleReturns',
-      // Call continuations
-      ['Continuation', true],
-      ['Continuation', false],
-    ]);
-    expect(ReactNoop.getChildren()).toEqual([
-      div(span('foo==bar'), span('foo!=bar')),
-    ]);
-  });
-
-  it('should update a call', () => {
-    function Continuation({isSame}) {
-      return <span prop={isSame ? 'foo==bar' : 'foo!=bar'} />;
-    }
-
-    function Child({bar}) {
-      return ReactCallReturn.unstable_createReturn({
-        props: {
-          bar: bar,
-        },
-        continuation: Continuation,
-      });
-    }
-
-    function Indirection() {
-      return [<Child key="a" bar={true} />, <Child key="b" bar={false} />];
-    }
-
-    function HandleReturns(props, returns) {
-      return returns.map((y, i) => (
-        <y.continuation key={i} isSame={props.foo === y.props.bar} />
-      ));
-    }
-
-    function Parent(props) {
-      return ReactCallReturn.unstable_createCall(
-        props.children,
-        HandleReturns,
-        props,
-      );
-    }
-
-    function App(props) {
-      return (
-        <div>
-          <Parent foo={props.foo}>
-            <Indirection />
-          </Parent>
-        </div>
-      );
-    }
-
-    ReactNoop.render(<App foo={true} />);
-    ReactNoop.flush();
-    expect(ReactNoop.getChildren()).toEqual([
-      div(span('foo==bar'), span('foo!=bar')),
-    ]);
-
-    ReactNoop.render(<App foo={false} />);
-    ReactNoop.flush();
-    expect(ReactNoop.getChildren()).toEqual([
-      div(span('foo!=bar'), span('foo==bar')),
-    ]);
-  });
-
-  it('should unmount a composite in a call', () => {
-    let ops = [];
-
-    class Continuation extends React.Component {
-      render() {
-        ops.push('Continuation');
-        return <div />;
-      }
-      componentWillUnmount() {
-        ops.push('Unmount Continuation');
-      }
-    }
-
-    class Child extends React.Component {
-      render() {
-        ops.push('Child');
-        return ReactCallReturn.unstable_createReturn(Continuation);
-      }
-      componentWillUnmount() {
-        ops.push('Unmount Child');
-      }
-    }
-
-    function HandleReturns(props, returns) {
-      ops.push('HandleReturns');
-      return returns.map((ContinuationComponent, i) => (
-        <ContinuationComponent key={i} />
-      ));
-    }
-
-    class Parent extends React.Component {
-      render() {
-        ops.push('Parent');
-        return ReactCallReturn.unstable_createCall(
-          this.props.children,
-          HandleReturns,
-          this.props,
-        );
-      }
-      componentWillUnmount() {
-        ops.push('Unmount Parent');
-      }
-    }
-
-    ReactNoop.render(
-      <Parent>
-        <Child />
-      </Parent>,
-    );
-    ReactNoop.flush();
-
-    expect(ops).toEqual(['Parent', 'Child', 'HandleReturns', 'Continuation']);
-
-    ops = [];
-
-    ReactNoop.render(<div />);
-    ReactNoop.flush();
-
-    expect(ops).toEqual([
-      'Unmount Parent',
-      'Unmount Child',
-      'Unmount Continuation',
-    ]);
-  });
-
-  it('should handle deep updates in call', () => {
-    let instances = {};
-
-    class Counter extends React.Component {
-      state = {value: 5};
-      render() {
-        instances[this.props.id] = this;
-        return ReactCallReturn.unstable_createReturn(this.state.value);
-      }
-    }
-
-    function App(props) {
-      return ReactCallReturn.unstable_createCall(
-        [
-          <Counter key="a" id="a" />,
-          <Counter key="b" id="b" />,
-          <Counter key="c" id="c" />,
-        ],
-        (p, returns) => returns.map((y, i) => <span key={i} prop={y * 100} />),
-        {},
-      );
-    }
-
-    ReactNoop.render(<App />);
-    ReactNoop.flush();
-    expect(ReactNoop.getChildren()).toEqual([span(500), span(500), span(500)]);
-
-    instances.a.setState({value: 1});
-    instances.b.setState({value: 2});
-    ReactNoop.flush();
-    expect(ReactNoop.getChildren()).toEqual([span(100), span(200), span(500)]);
-  });
-
-  it('should unmount and remount children', () => {
-    let ops = [];
-
-    class Call extends React.Component {
-      render() {
-        return ReactCallReturn.unstable_createCall(
-          this.props.children,
-          (p, returns) => returns,
-          {},
-        );
-      }
-    }
-
-    class Return extends React.Component {
-      render() {
-        ops.push(`Return ${this.props.value}`);
-        return ReactCallReturn.unstable_createReturn(this.props.children);
-      }
-
-      UNSAFE_componentWillMount() {
-        ops.push(`Mount Return ${this.props.value}`);
-      }
-
-      componentWillUnmount() {
-        ops.push(`Unmount Return ${this.props.value}`);
-      }
-    }
-
-    ReactNoop.render(
-      <Call>
-        <Return value={1} />
-        <Return value={2} />
-      </Call>,
-    );
-    expect(ReactNoop.flush).toWarnDev(
-      'componentWillMount: Please update the following components ' +
-        'to use componentDidMount instead: Return',
-    );
-
-    expect(ops).toEqual([
-      'Mount Return 1',
-      'Return 1',
-      'Mount Return 2',
-      'Return 2',
-    ]);
-
-    ops = [];
-
-    ReactNoop.render(<Call />);
-    ReactNoop.flush();
-
-    expect(ops).toEqual(['Unmount Return 1', 'Unmount Return 2']);
-
-    ops = [];
-
-    ReactNoop.render(
-      <Call>
-        <Return value={3} />
-      </Call>,
-    );
-    ReactNoop.flush();
-
-    expect(ops).toEqual(['Mount Return 3', 'Return 3']);
-  });
-});
diff --git a/packages/react-dom/src/__tests__/ReactServerRendering-test.internal.js b/packages/react-dom/src/__tests__/ReactServerRendering-test.internal.js
index 05eb32ba037a8..b7c6eca3de0cc 100644
--- a/packages/react-dom/src/__tests__/ReactServerRendering-test.internal.js
+++ b/packages/react-dom/src/__tests__/ReactServerRendering-test.internal.js
@@ -11,7 +11,6 @@
 'use strict';
 
 let React;
-let ReactCallReturn;
 let ReactDOMServer;
 let PropTypes;
 
@@ -23,7 +22,6 @@ describe('ReactDOMServer', () => {
   beforeEach(() => {
     jest.resetModules();
     React = require('react');
-    ReactCallReturn = require('react-call-return');
     PropTypes = require('prop-types');
     ReactDOMServer = require('react-dom/server');
   });
@@ -623,25 +621,6 @@ describe('ReactDOMServer', () => {
     );
   });
 
-  it('should throw rendering call/return on the server', () => {
-    expect(() => {
-      ReactDOMServer.renderToString(
-        <div>{ReactCallReturn.unstable_createReturn(42)}</div>,
-      );
-    }).toThrow(
-      'The experimental Call and Return types are not currently supported by the server renderer.',
-    );
-    expect(() => {
-      ReactDOMServer.renderToString(
-        <div>
-          {ReactCallReturn.unstable_createCall(null, function() {}, {})}
-        </div>,
-      );
-    }).toThrow(
-      'The experimental Call and Return types are not currently supported by the server renderer.',
-    );
-  });
-
   it('should warn when server rendering a class with a render method that does not extend React.Component', () => {
     class ClassWithRenderNotExtended {
       render() {
diff --git a/packages/react-dom/src/server/ReactPartialRenderer.js b/packages/react-dom/src/server/ReactPartialRenderer.js
index d0cef9c60a4e8..59ea170b938d5 100644
--- a/packages/react-dom/src/server/ReactPartialRenderer.js
+++ b/packages/react-dom/src/server/ReactPartialRenderer.js
@@ -31,8 +31,6 @@ import {
   REACT_FRAGMENT_TYPE,
   REACT_STRICT_MODE_TYPE,
   REACT_ASYNC_MODE_TYPE,
-  REACT_CALL_TYPE,
-  REACT_RETURN_TYPE,
   REACT_PORTAL_TYPE,
   REACT_PROFILER_TYPE,
   REACT_PROVIDER_TYPE,
@@ -831,13 +829,6 @@ class ReactDOMServerRenderer {
           this.stack.push(frame);
           return '';
         }
-        case REACT_CALL_TYPE:
-        case REACT_RETURN_TYPE:
-          invariant(
-            false,
-            'The experimental Call and Return types are not currently ' +
-              'supported by the server renderer.',
-          );
         // eslint-disable-next-line-no-fallthrough
         default:
           break;
diff --git a/packages/react-reconciler/src/ReactDebugFiberPerf.js b/packages/react-reconciler/src/ReactDebugFiberPerf.js
index c2889986bff4e..7c2226f9a8529 100644
--- a/packages/react-reconciler/src/ReactDebugFiberPerf.js
+++ b/packages/react-reconciler/src/ReactDebugFiberPerf.js
@@ -16,8 +16,6 @@ import {
   HostComponent,
   HostText,
   HostPortal,
-  CallComponent,
-  ReturnComponent,
   Fragment,
   ContextProvider,
   ContextConsumer,
@@ -171,8 +169,6 @@ const shouldIgnoreFiber = (fiber: Fiber): boolean => {
     case HostComponent:
     case HostText:
     case HostPortal:
-    case CallComponent:
-    case ReturnComponent:
     case Fragment:
     case ContextProvider:
     case ContextConsumer:
diff --git a/packages/react-reconciler/src/ReactFiber.js b/packages/react-reconciler/src/ReactFiber.js
index 720fb9ffe1fb7..acfedb266c4ca 100644
--- a/packages/react-reconciler/src/ReactFiber.js
+++ b/packages/react-reconciler/src/ReactFiber.js
@@ -24,8 +24,6 @@ import {
   HostComponent,
   HostText,
   HostPortal,
-  CallComponent,
-  ReturnComponent,
   ForwardRef,
   Fragment,
   Mode,
@@ -41,8 +39,6 @@ import {NoContext, AsyncMode, ProfileMode, StrictMode} from './ReactTypeOfMode';
 import {
   REACT_FORWARD_REF_TYPE,
   REACT_FRAGMENT_TYPE,
-  REACT_RETURN_TYPE,
-  REACT_CALL_TYPE,
   REACT_STRICT_MODE_TYPE,
   REACT_PROFILER_TYPE,
   REACT_PROVIDER_TYPE,
@@ -364,12 +360,6 @@ export function createFiberFromElement(
         break;
       case REACT_PROFILER_TYPE:
         return createFiberFromProfiler(pendingProps, mode, expirationTime, key);
-      case REACT_CALL_TYPE:
-        fiberTag = CallComponent;
-        break;
-      case REACT_RETURN_TYPE:
-        fiberTag = ReturnComponent;
-        break;
       case REACT_TIMEOUT_TYPE:
         fiberTag = TimeoutComponent;
         // Suspense does not require async, but its children should be strict
diff --git a/packages/react-reconciler/src/ReactFiberBeginWork.js b/packages/react-reconciler/src/ReactFiberBeginWork.js
index d08ebd133024a..d344ce0998b42 100644
--- a/packages/react-reconciler/src/ReactFiberBeginWork.js
+++ b/packages/react-reconciler/src/ReactFiberBeginWork.js
@@ -27,9 +27,6 @@ import {
   HostComponent,
   HostText,
   HostPortal,
-  CallComponent,
-  CallHandlerPhase,
-  ReturnComponent,
   ForwardRef,
   Fragment,
   Mode,
@@ -741,44 +738,6 @@ export default function<T, P, I, TI, HI, PI, C, CC, CX, PL>(
     }
   }
 
-  function updateCallComponent(current, workInProgress, renderExpirationTime) {
-    let nextProps = workInProgress.pendingProps;
-    if (hasLegacyContextChanged()) {
-      // Normally we can bail out on props equality but if context has changed
-      // we don't do the bailout and we have to reuse existing props instead.
-    } else if (workInProgress.memoizedProps === nextProps) {
-      nextProps = workInProgress.memoizedProps;
-      // TODO: When bailing out, we might need to return the stateNode instead
-      // of the child. To check it for work.
-      // return bailoutOnAlreadyFinishedWork(current, workInProgress);
-    }
-
-    const nextChildren = nextProps.children;
-
-    // The following is a fork of reconcileChildrenAtExpirationTime but using
-    // stateNode to store the child.
-    if (current === null) {
-      workInProgress.stateNode = mountChildFibers(
-        workInProgress,
-        workInProgress.stateNode,
-        nextChildren,
-        renderExpirationTime,
-      );
-    } else {
-      workInProgress.stateNode = reconcileChildFibers(
-        workInProgress,
-        current.stateNode,
-        nextChildren,
-        renderExpirationTime,
-      );
-    }
-
-    memoizeProps(workInProgress, nextProps);
-    // This doesn't take arbitrary time so we could synchronously just begin
-    // eagerly do the work of workInProgress.child as an optimization.
-    return workInProgress.stateNode;
-  }
-
   function updateTimeoutComponent(
     current,
     workInProgress,
@@ -1260,20 +1219,6 @@ export default function<T, P, I, TI, HI, PI, C, CC, CX, PL>(
         );
       case HostText:
         return updateHostText(current, workInProgress);
-      case CallHandlerPhase:
-        // This is a restart. Reset the tag to the initial phase.
-        workInProgress.tag = CallComponent;
-      // Intentionally fall through since this is now the same.
-      case CallComponent:
-        return updateCallComponent(
-          current,
-          workInProgress,
-          renderExpirationTime,
-        );
-      case ReturnComponent:
-        // A return component is just a placeholder, we can just run through the
-        // next one immediately.
-        return null;
       case TimeoutComponent:
         return updateTimeoutComponent(
           current,
diff --git a/packages/react-reconciler/src/ReactFiberCommitWork.js b/packages/react-reconciler/src/ReactFiberCommitWork.js
index f3184ced83c83..ebe37ef5a0952 100644
--- a/packages/react-reconciler/src/ReactFiberCommitWork.js
+++ b/packages/react-reconciler/src/ReactFiberCommitWork.js
@@ -25,7 +25,6 @@ import {
   HostComponent,
   HostText,
   HostPortal,
-  CallComponent,
   Profiler,
   TimeoutComponent,
 } from 'shared/ReactTypeOfWork';
@@ -393,10 +392,6 @@ export default function<T, P, I, TI, HI, PI, C, CC, CX, PL>(
         safelyDetachRef(current);
         return;
       }
-      case CallComponent: {
-        commitNestedUnmounts(current.stateNode);
-        return;
-      }
       case HostPortal: {
         // TODO: this is recursive.
         // We are also not using this parent because
diff --git a/packages/react-reconciler/src/ReactFiberCompleteWork.js b/packages/react-reconciler/src/ReactFiberCompleteWork.js
index ab55061b12430..9d2cec1f3586f 100644
--- a/packages/react-reconciler/src/ReactFiberCompleteWork.js
+++ b/packages/react-reconciler/src/ReactFiberCompleteWork.js
@@ -31,9 +31,6 @@ import {
   HostComponent,
   HostText,
   HostPortal,
-  CallComponent,
-  CallHandlerPhase,
-  ReturnComponent,
   ContextProvider,
   ContextConsumer,
   ForwardRef,
@@ -45,8 +42,6 @@ import {
 import {Placement, Ref, Update} from 'shared/ReactTypeOfSideEffect';
 import invariant from 'fbjs/lib/invariant';
 
-import {reconcileChildFibers} from './ReactChildFiber';
-
 export default function<T, P, I, TI, HI, PI, C, CC, CX, PL>(
   config: HostConfig<T, P, I, TI, HI, PI, C, CC, CX, PL>,
   hostContext: HostContext<C, CX>,
@@ -97,75 +92,6 @@ export default function<T, P, I, TI, HI, PI, C, CC, CX, PL>(
     workInProgress.effectTag |= Ref;
   }
 
-  function appendAllReturns(returns: Array<mixed>, workInProgress: Fiber) {
-    let node = workInProgress.stateNode;
-    if (node) {
-      node.return = workInProgress;
-    }
-    while (node !== null) {
-      if (
-        node.tag === HostComponent ||
-        node.tag === HostText ||
-        node.tag === HostPortal
-      ) {
-        invariant(false, 'A call cannot have host component children.');
-      } else if (node.tag === ReturnComponent) {
-        returns.push(node.pendingProps.value);
-      } else if (node.child !== null) {
-        node.child.return = node;
-        node = node.child;
-        continue;
-      }
-      while (node.sibling === null) {
-        if (node.return === null || node.return === workInProgress) {
-          return;
-        }
-        node = node.return;
-      }
-      node.sibling.return = node.return;
-      node = node.sibling;
-    }
-  }
-
-  function moveCallToHandlerPhase(
-    current: Fiber | null,
-    workInProgress: Fiber,
-    renderExpirationTime: ExpirationTime,
-  ) {
-    const props = workInProgress.memoizedProps;
-    invariant(
-      props,
-      'Should be resolved by now. This error is likely caused by a bug in ' +
-        'React. Please file an issue.',
-    );
-
-    // First step of the call has completed. Now we need to do the second.
-    // TODO: It would be nice to have a multi stage call represented by a
-    // single component, or at least tail call optimize nested ones. Currently
-    // that requires additional fields that we don't want to add to the fiber.
-    // So this requires nested handlers.
-    // Note: This doesn't mutate the alternate node. I don't think it needs to
-    // since this stage is reset for every pass.
-    workInProgress.tag = CallHandlerPhase;
-
-    // Build up the returns.
-    // TODO: Compare this to a generator or opaque helpers like Children.
-    const returns: Array<mixed> = [];
-    appendAllReturns(returns, workInProgress);
-    const fn = props.handler;
-    const childProps = props.props;
-    const nextChildren = fn(childProps, returns);
-
-    const currentFirstChild = current !== null ? current.child : null;
-    workInProgress.child = reconcileChildFibers(
-      workInProgress,
-      currentFirstChild,
-      nextChildren,
-      renderExpirationTime,
-    );
-    return workInProgress.child;
-  }
-
   function appendAllChildren(parent: I, workInProgress: Fiber) {
     // We only have the top Fiber that was created but we need recurse down its
     // children to find all the terminal nodes.
@@ -579,19 +505,6 @@ export default function<T, P, I, TI, HI, PI, C, CC, CX, PL>(
         }
         return null;
       }
-      case CallComponent:
-        return moveCallToHandlerPhase(
-          current,
-          workInProgress,
-          renderExpirationTime,
-        );
-      case CallHandlerPhase:
-        // Reset the tag to now be a first phase call.
-        workInProgress.tag = CallComponent;
-        return null;
-      case ReturnComponent:
-        // Does nothing.
-        return null;
       case ForwardRef:
         return null;
       case TimeoutComponent:
diff --git a/packages/react-reconciler/src/__tests__/ReactIncrementalPerf-test.internal.js b/packages/react-reconciler/src/__tests__/ReactIncrementalPerf-test.internal.js
index 1e33804d12f4a..cf89594aaf1de 100644
--- a/packages/react-reconciler/src/__tests__/ReactIncrementalPerf-test.internal.js
+++ b/packages/react-reconciler/src/__tests__/ReactIncrementalPerf-test.internal.js
@@ -12,7 +12,6 @@
 
 describe('ReactDebugFiberPerf', () => {
   let React;
-  let ReactCallReturn;
   let ReactNoop;
   let PropTypes;
 
@@ -121,7 +120,6 @@ describe('ReactDebugFiberPerf', () => {
     // Import after the polyfill is set up:
     React = require('react');
     ReactNoop = require('react-noop-renderer');
-    ReactCallReturn = require('react-call-return');
     PropTypes = require('prop-types');
   });
 
@@ -535,53 +533,6 @@ describe('ReactDebugFiberPerf', () => {
     expect(getFlameChart()).toMatchSnapshot();
   });
 
-  it('supports returns', () => {
-    function Continuation({isSame}) {
-      return <span prop={isSame ? 'foo==bar' : 'foo!=bar'} />;
-    }
-
-    function CoChild({bar}) {
-      return ReactCallReturn.unstable_createReturn({
-        props: {
-          bar: bar,
-        },
-        continuation: Continuation,
-      });
-    }
-
-    function Indirection() {
-      return [<CoChild key="a" bar={true} />, <CoChild key="b" bar={false} />];
-    }
-
-    function HandleReturns(props, returns) {
-      return returns.map((y, i) => (
-        <y.continuation key={i} isSame={props.foo === y.props.bar} />
-      ));
-    }
-
-    function CoParent(props) {
-      return ReactCallReturn.unstable_createCall(
-        props.children,
-        HandleReturns,
-        props,
-      );
-    }
-
-    function App() {
-      return (
-        <div>
-          <CoParent foo={true}>
-            <Indirection />
-          </CoParent>
-        </div>
-      );
-    }
-
-    ReactNoop.render(<App />);
-    ReactNoop.flush();
-    expect(getFlameChart()).toMatchSnapshot();
-  });
-
   it('supports portals', () => {
     const noopContainer = {children: []};
     ReactNoop.render(
diff --git a/packages/react-reconciler/src/__tests__/__snapshots__/ReactIncrementalPerf-test.internal.js.snap b/packages/react-reconciler/src/__tests__/__snapshots__/ReactIncrementalPerf-test.internal.js.snap
index 4ef5ab820199f..a1e4a1cd8380a 100644
--- a/packages/react-reconciler/src/__tests__/__snapshots__/ReactIncrementalPerf-test.internal.js.snap
+++ b/packages/react-reconciler/src/__tests__/__snapshots__/ReactIncrementalPerf-test.internal.js.snap
@@ -370,25 +370,6 @@ exports[`ReactDebugFiberPerf supports portals 1`] = `
 "
 `;
 
-exports[`ReactDebugFiberPerf supports returns 1`] = `
-"⚛ (Waiting for async callback... will force flush in 5250 ms)
-
-⚛ (React Tree Reconciliation: Completed Root)
-  ⚛ App [mount]
-    ⚛ CoParent [mount]
-      ⚛ Indirection [mount]
-        ⚛ CoChild [mount]
-        ⚛ CoChild [mount]
-      ⚛ Continuation [mount]
-      ⚛ Continuation [mount]
-
-⚛ (Committing Changes)
-  ⚛ (Committing Snapshot Effects: 0 Total)
-  ⚛ (Committing Host Effects: 3 Total)
-  ⚛ (Calling Lifecycle Methods: 0 Total)
-"
-`;
-
 exports[`ReactDebugFiberPerf warns if an in-progress update is interrupted 1`] = `
 "⚛ (Waiting for async callback... will force flush in 5250 ms)
 
diff --git a/packages/react/src/__tests__/ReactChildren-test.js b/packages/react/src/__tests__/ReactChildren-test.js
index ce639254340cf..cf5edb52bd521 100644
--- a/packages/react/src/__tests__/ReactChildren-test.js
+++ b/packages/react/src/__tests__/ReactChildren-test.js
@@ -69,57 +69,6 @@ describe('ReactChildren', () => {
     expect(mappedChildren[0]).toEqual(reactPortal);
   });
 
-  it('should support Call components', () => {
-    const context = {};
-    const callback = jasmine.createSpy().and.callFake(function(kid, index) {
-      expect(this).toBe(context);
-      return kid;
-    });
-    const ReactCallReturn = require('react-call-return');
-    const reactCall = ReactCallReturn.unstable_createCall(
-      <span key="simple" />,
-      () => {},
-    );
-
-    const parentInstance = <div>{reactCall}</div>;
-    React.Children.forEach(parentInstance.props.children, callback, context);
-    expect(callback).toHaveBeenCalledWith(reactCall, 0);
-    callback.calls.reset();
-    const mappedChildren = React.Children.map(
-      parentInstance.props.children,
-      callback,
-      context,
-    );
-    expect(callback).toHaveBeenCalledWith(reactCall, 0);
-    expect(mappedChildren[0].type).toEqual(reactCall.type);
-    expect(mappedChildren[0].props).toEqual(reactCall.props);
-  });
-
-  it('should support Return components', () => {
-    const context = {};
-    const callback = jasmine.createSpy().and.callFake(function(kid, index) {
-      expect(this).toBe(context);
-      return kid;
-    });
-    const ReactCallReturn = require('react-call-return');
-    const reactReturn = ReactCallReturn.unstable_createReturn(
-      <span key="simple" />,
-    );
-
-    const parentInstance = <div>{reactReturn}</div>;
-    React.Children.forEach(parentInstance.props.children, callback, context);
-    expect(callback).toHaveBeenCalledWith(reactReturn, 0);
-    callback.calls.reset();
-    const mappedChildren = React.Children.map(
-      parentInstance.props.children,
-      callback,
-      context,
-    );
-    expect(callback).toHaveBeenCalledWith(reactReturn, 0);
-    expect(mappedChildren[0].props).toEqual(reactReturn.props);
-    expect(mappedChildren[0].type).toEqual(reactReturn.type);
-  });
-
   it('should treat single arrayless child as being in array', () => {
     const context = {};
     const callback = jasmine.createSpy().and.callFake(function(kid, index) {
diff --git a/packages/shared/ReactSymbols.js b/packages/shared/ReactSymbols.js
index 9dc1d3627ab40..bd3af4a903e94 100644
--- a/packages/shared/ReactSymbols.js
+++ b/packages/shared/ReactSymbols.js
@@ -14,10 +14,6 @@ const hasSymbol = typeof Symbol === 'function' && Symbol.for;
 export const REACT_ELEMENT_TYPE = hasSymbol
   ? Symbol.for('react.element')
   : 0xeac7;
-export const REACT_CALL_TYPE = hasSymbol ? Symbol.for('react.call') : 0xeac8;
-export const REACT_RETURN_TYPE = hasSymbol
-  ? Symbol.for('react.return')
-  : 0xeac9;
 export const REACT_PORTAL_TYPE = hasSymbol
   ? Symbol.for('react.portal')
   : 0xeaca;
diff --git a/packages/shared/ReactTypeOfWork.js b/packages/shared/ReactTypeOfWork.js
index e6c1ace1d9dd9..5ac284818a120 100644
--- a/packages/shared/ReactTypeOfWork.js
+++ b/packages/shared/ReactTypeOfWork.js
@@ -33,9 +33,9 @@ export const HostRoot = 3; // Root of a host tree. Could be nested inside anothe
 export const HostPortal = 4; // A subtree. Could be an entry point to a different renderer.
 export const HostComponent = 5;
 export const HostText = 6;
-export const CallComponent = 7;
-export const CallHandlerPhase = 8;
-export const ReturnComponent = 9;
+export const CallComponent_UNUSED = 7;
+export const CallHandlerPhase_UNUSED = 8;
+export const ReturnComponent_UNUSED = 9;
 export const Fragment = 10;
 export const Mode = 11;
 export const ContextConsumer = 12;
diff --git a/packages/shared/getComponentName.js b/packages/shared/getComponentName.js
index a5f61c5efccfc..b79a2d1c9bfa8 100644
--- a/packages/shared/getComponentName.js
+++ b/packages/shared/getComponentName.js
@@ -11,14 +11,12 @@ import type {Fiber} from 'react-reconciler/src/ReactFiber';
 
 import {
   REACT_ASYNC_MODE_TYPE,
-  REACT_CALL_TYPE,
   REACT_CONTEXT_TYPE,
   REACT_FORWARD_REF_TYPE,
   REACT_FRAGMENT_TYPE,
   REACT_PORTAL_TYPE,
   REACT_PROFILER_TYPE,
   REACT_PROVIDER_TYPE,
-  REACT_RETURN_TYPE,
   REACT_STRICT_MODE_TYPE,
 } from 'shared/ReactSymbols';
 
@@ -33,8 +31,6 @@ function getComponentName(fiber: Fiber): string | null {
   switch (type) {
     case REACT_ASYNC_MODE_TYPE:
       return 'AsyncMode';
-    case REACT_CALL_TYPE:
-      return 'ReactCall';
     case REACT_CONTEXT_TYPE:
       return 'Context.Consumer';
     case REACT_FRAGMENT_TYPE:
@@ -45,8 +41,6 @@ function getComponentName(fiber: Fiber): string | null {
       return `Profiler(${fiber.pendingProps.id})`;
     case REACT_PROVIDER_TYPE:
       return 'Context.Provider';
-    case REACT_RETURN_TYPE:
-      return 'ReactReturn';
     case REACT_STRICT_MODE_TYPE:
       return 'StrictMode';
   }
diff --git a/scripts/rollup/bundles.js b/scripts/rollup/bundles.js
index e9f54a11dee65..ae5729a748f3a 100644
--- a/scripts/rollup/bundles.js
+++ b/scripts/rollup/bundles.js
@@ -328,16 +328,6 @@ const bundles = [
     externals: [],
   },
 
-  /******* React Call Return (experimental) *******/
-  {
-    label: 'react-call-return',
-    bundleTypes: [NODE_DEV, NODE_PROD],
-    moduleType: ISOMORPHIC,
-    entry: 'react-call-return',
-    global: 'ReactCallReturn',
-    externals: [],
-  },
-
   /******* React Is *******/
   {
     label: 'react-is',