diff --git a/packages/react-dom/src/client/ReactDOMFiberComponent.js b/packages/react-dom/src/client/ReactDOMFiberComponent.js
index c7ec03ed12..2839a92fb4 100644
--- a/packages/react-dom/src/client/ReactDOMFiberComponent.js
+++ b/packages/react-dom/src/client/ReactDOMFiberComponent.js
@@ -8,7 +8,10 @@
  */
 
 // TODO: direct imports like some-package/src/* are bad. Fix me.
-import ReactDebugCurrentFiber from 'react-reconciler/src/ReactDebugCurrentFiber';
+import {
+  getCurrentFiberOwnerNameInDevOrNull,
+  getCurrentFiberStackInDevOrNull,
+} from 'react-reconciler/src/ReactCurrentFiber';
 import {registrationNameModules} from 'events/EventPluginRegistry';
 import warning from 'shared/warning';
 
@@ -45,10 +48,6 @@ import {validateProperties as validateARIAProperties} from '../shared/ReactDOMIn
 import {validateProperties as validateInputProperties} from '../shared/ReactDOMNullInputValuePropHook';
 import {validateProperties as validateUnknownProperties} from '../shared/ReactDOMUnknownPropertyHook';
 
-const {
-  getCurrentFiberOwnerName,
-  getCurrentFiberStackAddendum,
-} = ReactDebugCurrentFiber;
 let didWarnInvalidHydration = false;
 let didWarnShadyDOM = false;
 
@@ -62,7 +61,7 @@ const HTML = '__html';
 
 const {html: HTML_NAMESPACE} = Namespaces;
 
-let getStack = () => '';
+let getStackInDevOrNull = () => '';
 
 let warnedUnknownTags;
 let suppressHydrationWarning;
@@ -77,7 +76,7 @@ let normalizeMarkupForTextOrAttribute;
 let normalizeHTML;
 
 if (__DEV__) {
-  getStack = getCurrentFiberStackAddendum;
+  getStackInDevOrNull = getCurrentFiberStackInDevOrNull;
 
   warnedUnknownTags = {
     // Chrome is the only major browser not shipping <time>. But as of July
@@ -181,7 +180,7 @@ if (__DEV__) {
         registrationName,
         registrationName,
         registrationName,
-        getCurrentFiberStackAddendum(),
+        getCurrentFiberStackInDevOrNull(),
       );
     } else {
       warning(
@@ -189,7 +188,7 @@ if (__DEV__) {
         'Expected `%s` listener to be a function, instead got a value of `%s` type.%s',
         registrationName,
         typeof listener,
-        getCurrentFiberStackAddendum(),
+        getCurrentFiberStackInDevOrNull(),
       );
     }
   };
@@ -267,7 +266,11 @@ function setInitialDOMProperties(
         }
       }
       // Relies on `updateStylesByID` not mutating `styleUpdates`.
-      CSSPropertyOperations.setValueForStyles(domElement, nextProp, getStack);
+      CSSPropertyOperations.setValueForStyles(
+        domElement,
+        nextProp,
+        getStackInDevOrNull,
+      );
     } else if (propKey === DANGEROUSLY_SET_INNER_HTML) {
       const nextHtml = nextProp ? nextProp[HTML] : undefined;
       if (nextHtml != null) {
@@ -323,7 +326,11 @@ function updateDOMProperties(
     const propKey = updatePayload[i];
     const propValue = updatePayload[i + 1];
     if (propKey === STYLE) {
-      CSSPropertyOperations.setValueForStyles(domElement, propValue, getStack);
+      CSSPropertyOperations.setValueForStyles(
+        domElement,
+        propValue,
+        getStackInDevOrNull,
+      );
     } else if (propKey === DANGEROUSLY_SET_INNER_HTML) {
       setInnerHTML(domElement, propValue);
     } else if (propKey === CHILDREN) {
@@ -442,7 +449,7 @@ export function setInitialProperties(
         false,
         '%s is using shady DOM. Using shady DOM with React can ' +
           'cause things to break subtly.',
-        getCurrentFiberOwnerName() || 'A component',
+        getCurrentFiberOwnerNameInDevOrNull() || 'A component',
       );
       didWarnShadyDOM = true;
     }
@@ -516,7 +523,7 @@ export function setInitialProperties(
       props = rawProps;
   }
 
-  assertValidProps(tag, props, getStack);
+  assertValidProps(tag, props, getStackInDevOrNull);
 
   setInitialDOMProperties(
     tag,
@@ -604,7 +611,7 @@ export function diffProperties(
       break;
   }
 
-  assertValidProps(tag, nextProps, getStack);
+  assertValidProps(tag, nextProps, getStackInDevOrNull);
 
   let propKey;
   let styleName;
@@ -834,7 +841,7 @@ export function diffHydratedProperties(
         false,
         '%s is using shady DOM. Using shady DOM with React can ' +
           'cause things to break subtly.',
-        getCurrentFiberOwnerName() || 'A component',
+        getCurrentFiberOwnerNameInDevOrNull() || 'A component',
       );
       didWarnShadyDOM = true;
     }
@@ -895,7 +902,7 @@ export function diffHydratedProperties(
       break;
   }
 
-  assertValidProps(tag, rawProps, getStack);
+  assertValidProps(tag, rawProps, getStackInDevOrNull);
 
   if (__DEV__) {
     extraAttributeNames = new Set();
diff --git a/packages/react-dom/src/client/ReactDOMFiberInput.js b/packages/react-dom/src/client/ReactDOMFiberInput.js
index 07b4752182..82603a64ca 100644
--- a/packages/react-dom/src/client/ReactDOMFiberInput.js
+++ b/packages/react-dom/src/client/ReactDOMFiberInput.js
@@ -8,7 +8,10 @@
  */
 
 // TODO: direct imports like some-package/src/* are bad. Fix me.
-import ReactDebugCurrentFiber from 'react-reconciler/src/ReactDebugCurrentFiber';
+import {
+  getCurrentFiberOwnerNameInDevOrNull,
+  getCurrentFiberStackInDevOrNull,
+} from 'react-reconciler/src/ReactCurrentFiber';
 import invariant from 'shared/invariant';
 import warning from 'shared/warning';
 
@@ -25,10 +28,6 @@ type InputWithWrapperState = HTMLInputElement & {
   },
 };
 
-const {
-  getCurrentFiberOwnerName,
-  getCurrentFiberStackAddendum,
-} = ReactDebugCurrentFiber;
 let didWarnValueDefaultValue = false;
 let didWarnCheckedDefaultChecked = false;
 let didWarnControlledToUncontrolled = false;
@@ -75,7 +74,7 @@ export function initWrapperState(element: Element, props: Object) {
     ReactControlledValuePropTypes.checkPropTypes(
       'input',
       props,
-      getCurrentFiberStackAddendum,
+      getCurrentFiberStackInDevOrNull,
     );
 
     if (
@@ -91,7 +90,7 @@ export function initWrapperState(element: Element, props: Object) {
           'both). Decide between using a controlled or uncontrolled input ' +
           'element and remove one of these props. More info: ' +
           'https://fb.me/react-controlled-components',
-        getCurrentFiberOwnerName() || 'A component',
+        getCurrentFiberOwnerNameInDevOrNull() || 'A component',
         props.type,
       );
       didWarnCheckedDefaultChecked = true;
@@ -109,7 +108,7 @@ export function initWrapperState(element: Element, props: Object) {
           'both). Decide between using a controlled or uncontrolled input ' +
           'element and remove one of these props. More info: ' +
           'https://fb.me/react-controlled-components',
-        getCurrentFiberOwnerName() || 'A component',
+        getCurrentFiberOwnerNameInDevOrNull() || 'A component',
         props.type,
       );
       didWarnValueDefaultValue = true;
@@ -154,7 +153,7 @@ export function updateWrapper(element: Element, props: Object) {
           'Decide between using a controlled or uncontrolled input ' +
           'element for the lifetime of the component. More info: https://fb.me/react-controlled-components%s',
         props.type,
-        getCurrentFiberStackAddendum(),
+        getCurrentFiberStackInDevOrNull(),
       );
       didWarnUncontrolledToControlled = true;
     }
@@ -170,7 +169,7 @@ export function updateWrapper(element: Element, props: Object) {
           'Decide between using a controlled or uncontrolled input ' +
           'element for the lifetime of the component. More info: https://fb.me/react-controlled-components%s',
         props.type,
-        getCurrentFiberStackAddendum(),
+        getCurrentFiberStackInDevOrNull(),
       );
       didWarnControlledToUncontrolled = true;
     }
diff --git a/packages/react-dom/src/client/ReactDOMFiberSelect.js b/packages/react-dom/src/client/ReactDOMFiberSelect.js
index 21c7e62ece..1f03a93a05 100644
--- a/packages/react-dom/src/client/ReactDOMFiberSelect.js
+++ b/packages/react-dom/src/client/ReactDOMFiberSelect.js
@@ -8,16 +8,14 @@
  */
 
 // TODO: direct imports like some-package/src/* are bad. Fix me.
-import ReactDebugCurrentFiber from 'react-reconciler/src/ReactDebugCurrentFiber';
+import {
+  getCurrentFiberOwnerNameInDevOrNull,
+  getCurrentFiberStackInDevOrNull,
+} from 'react-reconciler/src/ReactCurrentFiber';
 import warning from 'shared/warning';
 
 import ReactControlledValuePropTypes from '../shared/ReactControlledValuePropTypes';
 
-const {
-  getCurrentFiberOwnerName,
-  getCurrentFiberStackAddendum,
-} = ReactDebugCurrentFiber;
-
 let didWarnValueDefaultValue;
 
 if (__DEV__) {
@@ -32,7 +30,7 @@ type SelectWithWrapperState = HTMLSelectElement & {
 };
 
 function getDeclarationErrorAddendum() {
-  const ownerName = getCurrentFiberOwnerName();
+  const ownerName = getCurrentFiberOwnerNameInDevOrNull();
   if (ownerName) {
     return '\n\nCheck the render method of `' + ownerName + '`.';
   }
@@ -48,7 +46,7 @@ function checkSelectPropTypes(props) {
   ReactControlledValuePropTypes.checkPropTypes(
     'select',
     props,
-    getCurrentFiberStackAddendum,
+    getCurrentFiberStackInDevOrNull,
   );
 
   for (let i = 0; i < valuePropNames.length; i++) {
diff --git a/packages/react-dom/src/client/ReactDOMFiberTextarea.js b/packages/react-dom/src/client/ReactDOMFiberTextarea.js
index 4ff024895e..6ffe3db6d3 100644
--- a/packages/react-dom/src/client/ReactDOMFiberTextarea.js
+++ b/packages/react-dom/src/client/ReactDOMFiberTextarea.js
@@ -10,11 +10,10 @@
 import invariant from 'shared/invariant';
 import warning from 'shared/warning';
 // TODO: direct imports like some-package/src/* are bad. Fix me.
-import ReactDebugCurrentFiber from 'react-reconciler/src/ReactDebugCurrentFiber';
+import {getCurrentFiberStackInDevOrNull} from 'react-reconciler/src/ReactCurrentFiber';
 
 import ReactControlledValuePropTypes from '../shared/ReactControlledValuePropTypes';
 
-const {getCurrentFiberStackAddendum} = ReactDebugCurrentFiber;
 let didWarnValDefaultVal = false;
 
 type TextAreaWithWrapperState = HTMLTextAreaElement & {
@@ -68,7 +67,7 @@ export function initWrapperState(element: Element, props: Object) {
     ReactControlledValuePropTypes.checkPropTypes(
       'textarea',
       props,
-      getCurrentFiberStackAddendum,
+      getCurrentFiberStackInDevOrNull,
     );
     if (
       props.value !== undefined &&
diff --git a/packages/react-dom/src/client/validateDOMNesting.js b/packages/react-dom/src/client/validateDOMNesting.js
index 3d3e17cd25..ea7e5f12dd 100644
--- a/packages/react-dom/src/client/validateDOMNesting.js
+++ b/packages/react-dom/src/client/validateDOMNesting.js
@@ -7,9 +7,8 @@
 
 import warning from 'shared/warning';
 // TODO: direct imports like some-package/src/* are bad. Fix me.
-import ReactDebugCurrentFiber from 'react-reconciler/src/ReactDebugCurrentFiber';
+import {getCurrentFiberStackInDevOrNull} from 'react-reconciler/src/ReactCurrentFiber';
 
-const {getCurrentFiberStackAddendum} = ReactDebugCurrentFiber;
 let validateDOMNesting = () => {};
 
 if (__DEV__) {
@@ -427,7 +426,7 @@ if (__DEV__) {
     }
 
     const ancestorTag = invalidParentOrAncestor.tag;
-    const addendum = getCurrentFiberStackAddendum();
+    const addendum = getCurrentFiberStackInDevOrNull();
 
     const warnKey =
       !!invalidParent + '|' + childTag + '|' + ancestorTag + '|' + addendum;
diff --git a/packages/react-native-renderer/src/ReactNativeRenderer.js b/packages/react-native-renderer/src/ReactNativeRenderer.js
index 9ff1749c50..5f044f5f2a 100644
--- a/packages/react-native-renderer/src/ReactNativeRenderer.js
+++ b/packages/react-native-renderer/src/ReactNativeRenderer.js
@@ -13,14 +13,14 @@ import type {ReactNodeList} from 'shared/ReactTypes';
 import './ReactNativeInjection';
 
 import * as ReactNativeFiberRenderer from 'react-reconciler/inline.native';
+// TODO: direct imports like some-package/src/* are bad. Fix me.
+import {getStackByFiberInDevAndProd} from 'react-reconciler/src/ReactCurrentFiber';
 import * as ReactPortal from 'shared/ReactPortal';
 import * as ReactGenericBatching from 'events/ReactGenericBatching';
 import ReactVersion from 'shared/ReactVersion';
 // Module provided by RN:
 import UIManager from 'UIManager';
 
-import {getStackAddendumByWorkInProgressFiber} from 'shared/ReactFiberComponentTreeHook';
-
 import NativeMethodsMixin from './NativeMethodsMixin';
 import ReactNativeComponent from './ReactNativeComponent';
 import * as ReactNativeComponentTree from './ReactNativeComponentTree';
@@ -80,7 +80,7 @@ function computeComponentStackForErrorReporting(reactTag: number): string {
   if (!fiber) {
     return '';
   }
-  return getStackAddendumByWorkInProgressFiber(fiber);
+  return getStackByFiberInDevAndProd(fiber);
 }
 
 const roots = new Map();
diff --git a/packages/react-reconciler/src/ReactCapturedValue.js b/packages/react-reconciler/src/ReactCapturedValue.js
index 1f6543b246..4fa8d72082 100644
--- a/packages/react-reconciler/src/ReactCapturedValue.js
+++ b/packages/react-reconciler/src/ReactCapturedValue.js
@@ -9,7 +9,7 @@
 
 import type {Fiber} from './ReactFiber';
 
-import {getStackAddendumByWorkInProgressFiber} from 'shared/ReactFiberComponentTreeHook';
+import {getStackByFiberInDevAndProd} from './ReactCurrentFiber';
 
 export type CapturedValue<T> = {
   value: T,
@@ -36,6 +36,6 @@ export function createCapturedValue<T>(
   return {
     value,
     source,
-    stack: getStackAddendumByWorkInProgressFiber(source),
+    stack: getStackByFiberInDevAndProd(source),
   };
 }
diff --git a/packages/react-reconciler/src/ReactChildFiber.js b/packages/react-reconciler/src/ReactChildFiber.js
index 19bdfbd059..64922d94fd 100644
--- a/packages/react-reconciler/src/ReactChildFiber.js
+++ b/packages/react-reconciler/src/ReactChildFiber.js
@@ -27,7 +27,6 @@ import {
   HostPortal,
   Fragment,
 } from 'shared/ReactTypeOfWork';
-import {getStackAddendumByWorkInProgressFiber} from 'shared/ReactFiberComponentTreeHook';
 import invariant from 'shared/invariant';
 import warning from 'shared/warning';
 
@@ -39,11 +38,12 @@ import {
   createFiberFromPortal,
 } from './ReactFiber';
 import {emptyRefsObject} from './ReactFiberClassComponent';
-import ReactDebugCurrentFiber from './ReactDebugCurrentFiber';
+import {
+  getCurrentFiberStackInDevOrNull,
+  getStackByFiberInDevAndProd,
+} from './ReactCurrentFiber';
 import {StrictMode} from './ReactTypeOfMode';
 
-const {getCurrentFiberStackAddendum} = ReactDebugCurrentFiber;
-
 let didWarnAboutMaps;
 let didWarnAboutStringRefInStrictMode;
 let ownerHasKeyUseWarning;
@@ -80,7 +80,7 @@ if (__DEV__) {
       'Each child in an array or iterator should have a unique ' +
       '"key" prop. See https://fb.me/react-warning-keys for ' +
       'more information.' +
-      (getCurrentFiberStackAddendum() || '');
+      (getCurrentFiberStackInDevOrNull() || '');
     if (ownerHasKeyUseWarning[currentComponentErrorInfo]) {
       return;
     }
@@ -91,7 +91,7 @@ if (__DEV__) {
       'Each child in an array or iterator should have a unique ' +
         '"key" prop. See https://fb.me/react-warning-keys for ' +
         'more information.%s',
-      getCurrentFiberStackAddendum(),
+      getCurrentFiberStackInDevOrNull(),
     );
   };
 }
@@ -122,7 +122,7 @@ function coerceRef(
               '\n\nLearn more about using refs safely here:' +
               '\nhttps://fb.me/react-strict-mode-string-ref',
             mixedRef,
-            getStackAddendumByWorkInProgressFiber(returnFiber),
+            getStackByFiberInDevAndProd(returnFiber),
           );
           didWarnAboutStringRefInStrictMode[componentName] = true;
         }
@@ -197,7 +197,7 @@ function throwOnInvalidObjectType(returnFiber: Fiber, newChild: Object) {
       addendum =
         ' If you meant to render a collection of children, use an array ' +
         'instead.' +
-        (getCurrentFiberStackAddendum() || '');
+        (getCurrentFiberStackInDevOrNull() || '');
     }
     invariant(
       false,
@@ -215,7 +215,7 @@ function warnOnFunctionType() {
     'Functions are not valid as a React child. This may happen if ' +
     'you return a Component instead of <Component /> from render. ' +
     'Or maybe you meant to call this function rather than return it.' +
-    (getCurrentFiberStackAddendum() || '');
+    (getCurrentFiberStackInDevOrNull() || '');
 
   if (ownerHasFunctionTypeWarning[currentComponentErrorInfo]) {
     return;
@@ -227,7 +227,7 @@ function warnOnFunctionType() {
     'Functions are not valid as a React child. This may happen if ' +
       'you return a Component instead of <Component /> from render. ' +
       'Or maybe you meant to call this function rather than return it.%s',
-    getCurrentFiberStackAddendum() || '',
+    getCurrentFiberStackInDevOrNull() || '',
   );
 }
 
@@ -719,7 +719,7 @@ function ChildReconciler(shouldTrackSideEffects) {
               'duplicated and/or omitted — the behavior is unsupported and ' +
               'could change in a future version.%s',
             key,
-            getCurrentFiberStackAddendum(),
+            getCurrentFiberStackInDevOrNull(),
           );
           break;
         default:
@@ -912,7 +912,7 @@ function ChildReconciler(shouldTrackSideEffects) {
           'Using Maps as children is unsupported and will likely yield ' +
             'unexpected results. Convert it to a sequence/iterable of keyed ' +
             'ReactElements instead.%s',
-          getCurrentFiberStackAddendum(),
+          getCurrentFiberStackInDevOrNull(),
         );
         didWarnAboutMaps = true;
       }
diff --git a/packages/react-reconciler/src/ReactCurrentFiber.js b/packages/react-reconciler/src/ReactCurrentFiber.js
new file mode 100644
index 0000000000..22d6a557ed
--- /dev/null
+++ b/packages/react-reconciler/src/ReactCurrentFiber.js
@@ -0,0 +1,101 @@
+/**
+ * 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
+ */
+
+import {ReactDebugCurrentFrame} from 'shared/ReactGlobalSharedState';
+import {
+  IndeterminateComponent,
+  FunctionalComponent,
+  ClassComponent,
+  HostComponent,
+} from 'shared/ReactTypeOfWork';
+import describeComponentFrame from 'shared/describeComponentFrame';
+import getComponentName from 'shared/getComponentName';
+
+import type {Fiber} from './ReactFiber';
+
+type LifeCyclePhase = 'render' | 'getChildContext';
+
+function describeFiber(fiber: Fiber): string {
+  switch (fiber.tag) {
+    case IndeterminateComponent:
+    case FunctionalComponent:
+    case ClassComponent:
+    case HostComponent:
+      const owner = fiber._debugOwner;
+      const source = fiber._debugSource;
+      const name = getComponentName(fiber);
+      let ownerName = null;
+      if (owner) {
+        ownerName = getComponentName(owner);
+      }
+      return describeComponentFrame(name, source, ownerName);
+    default:
+      return '';
+  }
+}
+
+export function getStackByFiberInDevAndProd(workInProgress: Fiber): string {
+  let info = '';
+  let node = workInProgress;
+  do {
+    info += describeFiber(node);
+    node = node.return;
+  } while (node);
+  return info;
+}
+
+export let current: Fiber | null = null;
+export let phase: LifeCyclePhase | null = null;
+
+export function getCurrentFiberOwnerNameInDevOrNull(): string | null {
+  if (__DEV__) {
+    if (current === null) {
+      return null;
+    }
+    const owner = current._debugOwner;
+    if (owner !== null && typeof owner !== 'undefined') {
+      return getComponentName(owner);
+    }
+  }
+  return null;
+}
+
+export function getCurrentFiberStackInDevOrNull(): string | null {
+  if (__DEV__) {
+    if (current === null) {
+      return null;
+    }
+    // Safe because if current fiber exists, we are reconciling,
+    // and it is guaranteed to be the work-in-progress version.
+    return getStackByFiberInDevAndProd(current);
+  }
+  return null;
+}
+
+export function resetCurrentFiber() {
+  if (__DEV__) {
+    ReactDebugCurrentFrame.getCurrentStack = null;
+    current = null;
+    phase = null;
+  }
+}
+
+export function setCurrentFiber(fiber: Fiber) {
+  if (__DEV__) {
+    ReactDebugCurrentFrame.getCurrentStack = getCurrentFiberStackInDevOrNull;
+    current = fiber;
+    phase = null;
+  }
+}
+
+export function setCurrentPhase(lifeCyclePhase: LifeCyclePhase | null) {
+  if (__DEV__) {
+    phase = lifeCyclePhase;
+  }
+}
diff --git a/packages/react-reconciler/src/ReactDebugCurrentFiber.js b/packages/react-reconciler/src/ReactDebugCurrentFiber.js
deleted file mode 100644
index 7b0f6b5cf8..0000000000
--- a/packages/react-reconciler/src/ReactDebugCurrentFiber.js
+++ /dev/null
@@ -1,71 +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
- */
-
-import {ReactDebugCurrentFrame} from 'shared/ReactGlobalSharedState';
-import {getStackAddendumByWorkInProgressFiber} from 'shared/ReactFiberComponentTreeHook';
-import getComponentName from 'shared/getComponentName';
-
-import type {Fiber} from './ReactFiber';
-
-type LifeCyclePhase = 'render' | 'getChildContext';
-
-function getCurrentFiberOwnerName(): string | null {
-  if (__DEV__) {
-    const fiber = ReactDebugCurrentFiber.current;
-    if (fiber === null) {
-      return null;
-    }
-    const owner = fiber._debugOwner;
-    if (owner !== null && typeof owner !== 'undefined') {
-      return getComponentName(owner);
-    }
-  }
-  return null;
-}
-
-function getCurrentFiberStackAddendum(): string | null {
-  if (__DEV__) {
-    const fiber = ReactDebugCurrentFiber.current;
-    if (fiber === null) {
-      return null;
-    }
-    // Safe because if current fiber exists, we are reconciling,
-    // and it is guaranteed to be the work-in-progress version.
-    return getStackAddendumByWorkInProgressFiber(fiber);
-  }
-  return null;
-}
-
-function resetCurrentFiber() {
-  ReactDebugCurrentFrame.getCurrentStack = null;
-  ReactDebugCurrentFiber.current = null;
-  ReactDebugCurrentFiber.phase = null;
-}
-
-function setCurrentFiber(fiber: Fiber) {
-  ReactDebugCurrentFrame.getCurrentStack = getCurrentFiberStackAddendum;
-  ReactDebugCurrentFiber.current = fiber;
-  ReactDebugCurrentFiber.phase = null;
-}
-
-function setCurrentPhase(phase: LifeCyclePhase | null) {
-  ReactDebugCurrentFiber.phase = phase;
-}
-
-const ReactDebugCurrentFiber = {
-  current: (null: Fiber | null),
-  phase: (null: LifeCyclePhase | null),
-  resetCurrentFiber,
-  setCurrentFiber,
-  setCurrentPhase,
-  getCurrentFiberOwnerName,
-  getCurrentFiberStackAddendum,
-};
-
-export default ReactDebugCurrentFiber;
diff --git a/packages/react-reconciler/src/ReactFiberBeginWork.js b/packages/react-reconciler/src/ReactFiberBeginWork.js
index 9c95166258..2057dba048 100644
--- a/packages/react-reconciler/src/ReactFiberBeginWork.js
+++ b/packages/react-reconciler/src/ReactFiberBeginWork.js
@@ -50,7 +50,7 @@ import invariant from 'shared/invariant';
 import getComponentName from 'shared/getComponentName';
 import ReactStrictModeWarnings from './ReactStrictModeWarnings';
 import warning from 'shared/warning';
-import ReactDebugCurrentFiber from './ReactDebugCurrentFiber';
+import * as ReactCurrentFiber from './ReactCurrentFiber';
 import {cancelWorkTimer} from './ReactDebugFiberPerf';
 
 import {applyDerivedStateFromProps} from './ReactFiberClassComponent';
@@ -98,8 +98,6 @@ import {
 } from './ReactFiberClassComponent';
 import MAX_SIGNED_31_BIT_INT from './maxSigned31BitInt';
 
-const {getCurrentFiberStackAddendum} = ReactDebugCurrentFiber;
-
 let didWarnAboutBadClass;
 let didWarnAboutGetDerivedStateOnFunctionalComponent;
 let didWarnAboutStatelessRefs;
@@ -170,9 +168,9 @@ function updateForwardRef(current, workInProgress) {
   let nextChildren;
   if (__DEV__) {
     ReactCurrentOwner.current = workInProgress;
-    ReactDebugCurrentFiber.setCurrentPhase('render');
+    ReactCurrentFiber.setCurrentPhase('render');
     nextChildren = render(nextProps, ref);
-    ReactDebugCurrentFiber.setCurrentPhase(null);
+    ReactCurrentFiber.setCurrentPhase(null);
   } else {
     nextChildren = render(nextProps, ref);
   }
@@ -258,9 +256,9 @@ function updateFunctionalComponent(current, workInProgress) {
 
   if (__DEV__) {
     ReactCurrentOwner.current = workInProgress;
-    ReactDebugCurrentFiber.setCurrentPhase('render');
+    ReactCurrentFiber.setCurrentPhase('render');
     nextChildren = fn(nextProps, context);
-    ReactDebugCurrentFiber.setCurrentPhase(null);
+    ReactCurrentFiber.setCurrentPhase(null);
   } else {
     nextChildren = fn(nextProps, context);
   }
@@ -359,7 +357,7 @@ function finishClassComponent(
     }
   } else {
     if (__DEV__) {
-      ReactDebugCurrentFiber.setCurrentPhase('render');
+      ReactCurrentFiber.setCurrentPhase('render');
       nextChildren = instance.render();
       if (
         debugRenderPhaseSideEffects ||
@@ -368,7 +366,7 @@ function finishClassComponent(
       ) {
         instance.render();
       }
-      ReactDebugCurrentFiber.setCurrentPhase(null);
+      ReactCurrentFiber.setCurrentPhase(null);
     } else {
       nextChildren = instance.render();
     }
@@ -660,7 +658,7 @@ function mountIndeterminateComponent(
       }
       if (workInProgress.ref !== null) {
         let info = '';
-        const ownerName = ReactDebugCurrentFiber.getCurrentFiberOwnerName();
+        const ownerName = ReactCurrentFiber.getCurrentFiberOwnerNameInDevOrNull();
         if (ownerName) {
           info += '\n\nCheck the render method of `' + ownerName + '`.';
         }
@@ -677,7 +675,7 @@ function mountIndeterminateComponent(
             'Stateless function components cannot be given refs. ' +
               'Attempts to access this ref will fail.%s%s',
             info,
-            ReactDebugCurrentFiber.getCurrentFiberStackAddendum(),
+            ReactCurrentFiber.getCurrentFiberStackInDevOrNull(),
           );
         }
       }
@@ -935,7 +933,7 @@ function updateContextProvider(current, workInProgress, renderExpirationTime) {
         newProps,
         'prop',
         'Context.Provider',
-        getCurrentFiberStackAddendum,
+        ReactCurrentFiber.getCurrentFiberStackInDevOrNull,
       );
     }
   }
@@ -1069,9 +1067,9 @@ function updateContextConsumer(current, workInProgress, renderExpirationTime) {
   let newChildren;
   if (__DEV__) {
     ReactCurrentOwner.current = workInProgress;
-    ReactDebugCurrentFiber.setCurrentPhase('render');
+    ReactCurrentFiber.setCurrentPhase('render');
     newChildren = render(newValue);
-    ReactDebugCurrentFiber.setCurrentPhase(null);
+    ReactCurrentFiber.setCurrentPhase(null);
   } else {
     newChildren = render(newValue);
   }
diff --git a/packages/react-reconciler/src/ReactFiberCommitWork.js b/packages/react-reconciler/src/ReactFiberCommitWork.js
index 9eb54495a9..34ce416fbe 100644
--- a/packages/react-reconciler/src/ReactFiberCommitWork.js
+++ b/packages/react-reconciler/src/ReactFiberCommitWork.js
@@ -20,7 +20,6 @@ import type {ExpirationTime} from './ReactFiberExpirationTime';
 import type {CapturedValue, CapturedError} from './ReactCapturedValue';
 
 import {enableProfilerTimer, enableSuspense} from 'shared/ReactFeatureFlags';
-import {getCommitTime} from './ReactProfilerTimer';
 import {
   ClassComponent,
   HostRoot,
@@ -38,16 +37,17 @@ import {
   Snapshot,
   Update,
 } from 'shared/ReactTypeOfSideEffect';
-import {commitUpdateQueue} from './ReactUpdateQueue';
+import getComponentName from 'shared/getComponentName';
 import invariant from 'shared/invariant';
 import warning from 'shared/warning';
 
 import {Sync} from './ReactFiberExpirationTime';
 import {onCommitUnmount} from './ReactFiberDevToolsHook';
 import {startPhaseTimer, stopPhaseTimer} from './ReactDebugFiberPerf';
-import getComponentName from 'shared/getComponentName';
-import {getStackAddendumByWorkInProgressFiber} from 'shared/ReactFiberComponentTreeHook';
+import {getStackByFiberInDevAndProd} from './ReactCurrentFiber';
 import {logCapturedError} from './ReactFiberErrorLogger';
+import {getCommitTime} from './ReactProfilerTimer';
+import {commitUpdateQueue} from './ReactUpdateQueue';
 import {
   getPublicInstance,
   supportsMutation,
@@ -89,7 +89,7 @@ export function logError(boundary: Fiber, errorInfo: CapturedValue<mixed>) {
   const source = errorInfo.source;
   let stack = errorInfo.stack;
   if (stack === null && source !== null) {
-    stack = getStackAddendumByWorkInProgressFiber(source);
+    stack = getStackByFiberInDevAndProd(source);
   }
 
   const capturedError: CapturedError = {
@@ -373,7 +373,7 @@ function commitAttachRef(finishedWork: Fiber) {
             'Unexpected ref object provided for %s. ' +
               'Use either a ref-setter function or React.createRef().%s',
             getComponentName(finishedWork),
-            getStackAddendumByWorkInProgressFiber(finishedWork),
+            getStackByFiberInDevAndProd(finishedWork),
           );
         }
       }
diff --git a/packages/react-reconciler/src/ReactFiberContext.js b/packages/react-reconciler/src/ReactFiberContext.js
index 1a1a30f35e..a27515fec8 100644
--- a/packages/react-reconciler/src/ReactFiberContext.js
+++ b/packages/react-reconciler/src/ReactFiberContext.js
@@ -17,7 +17,7 @@ import invariant from 'shared/invariant';
 import warning from 'shared/warning';
 import checkPropTypes from 'prop-types/checkPropTypes';
 
-import ReactDebugCurrentFiber from './ReactDebugCurrentFiber';
+import * as ReactCurrentFiber from './ReactCurrentFiber';
 import {startPhaseTimer, stopPhaseTimer} from './ReactDebugFiberPerf';
 import {createCursor, push, pop} from './ReactFiberStack';
 
@@ -96,7 +96,7 @@ function getMaskedContext(
       context,
       'context',
       name,
-      ReactDebugCurrentFiber.getCurrentFiberStackAddendum,
+      ReactCurrentFiber.getCurrentFiberStackInDevOrNull,
     );
   }
 
@@ -177,13 +177,13 @@ function processChildContext(fiber: Fiber, parentContext: Object): Object {
 
   let childContext;
   if (__DEV__) {
-    ReactDebugCurrentFiber.setCurrentPhase('getChildContext');
+    ReactCurrentFiber.setCurrentPhase('getChildContext');
   }
   startPhaseTimer(fiber, 'getChildContext');
   childContext = instance.getChildContext();
   stopPhaseTimer();
   if (__DEV__) {
-    ReactDebugCurrentFiber.setCurrentPhase(null);
+    ReactCurrentFiber.setCurrentPhase(null);
   }
   for (let contextKey in childContext) {
     invariant(
@@ -205,7 +205,7 @@ function processChildContext(fiber: Fiber, parentContext: Object): Object {
       // context from the parent component instance. The stack will be missing
       // because it's outside of the reconciliation, and so the pointer has not
       // been set. This is rare and doesn't matter. We'll also remove that API.
-      ReactDebugCurrentFiber.getCurrentFiberStackAddendum,
+      ReactCurrentFiber.getCurrentFiberStackInDevOrNull,
     );
   }
 
diff --git a/packages/react-reconciler/src/ReactFiberReconciler.js b/packages/react-reconciler/src/ReactFiberReconciler.js
index 245b1654e2..3f8554fb5a 100644
--- a/packages/react-reconciler/src/ReactFiberReconciler.js
+++ b/packages/react-reconciler/src/ReactFiberReconciler.js
@@ -55,7 +55,7 @@ import {
 } from './ReactFiberScheduler';
 import {createUpdate, enqueueUpdate} from './ReactUpdateQueue';
 import ReactFiberInstrumentation from './ReactFiberInstrumentation';
-import ReactDebugCurrentFiber from './ReactDebugCurrentFiber';
+import * as ReactCurrentFiber from './ReactCurrentFiber';
 
 type OpaqueRoot = FiberRoot;
 
@@ -104,8 +104,8 @@ function scheduleRootUpdate(
 ) {
   if (__DEV__) {
     if (
-      ReactDebugCurrentFiber.phase === 'render' &&
-      ReactDebugCurrentFiber.current !== null &&
+      ReactCurrentFiber.phase === 'render' &&
+      ReactCurrentFiber.current !== null &&
       !didWarnAboutNestedUpdates
     ) {
       didWarnAboutNestedUpdates = true;
@@ -115,7 +115,7 @@ function scheduleRootUpdate(
           'triggering nested component updates from render is not allowed. ' +
           'If necessary, trigger nested updates in componentDidUpdate.\n\n' +
           'Check the render method of %s.',
-        getComponentName(ReactDebugCurrentFiber.current) || 'Unknown',
+        getComponentName(ReactCurrentFiber.current) || 'Unknown',
       );
     }
   }
diff --git a/packages/react-reconciler/src/ReactFiberScheduler.js b/packages/react-reconciler/src/ReactFiberScheduler.js
index f18d833438..e5f1c86ba1 100644
--- a/packages/react-reconciler/src/ReactFiberScheduler.js
+++ b/packages/react-reconciler/src/ReactFiberScheduler.js
@@ -12,7 +12,6 @@ import type {FiberRoot, Batch} from './ReactFiberRoot';
 import type {ExpirationTime} from './ReactFiberExpirationTime';
 
 import ReactErrorUtils from 'shared/ReactErrorUtils';
-import {getStackAddendumByWorkInProgressFiber} from 'shared/ReactFiberComponentTreeHook';
 import {ReactCurrentOwner} from 'shared/ReactGlobalSharedState';
 import ReactStrictModeWarnings from './ReactStrictModeWarnings';
 import {
@@ -56,7 +55,7 @@ import {
 } from './ReactFiberHostConfig';
 
 import ReactFiberInstrumentation from './ReactFiberInstrumentation';
-import ReactDebugCurrentFiber from './ReactDebugCurrentFiber';
+import * as ReactCurrentFiber from './ReactCurrentFiber';
 import {
   now,
   scheduleDeferredCallback,
@@ -185,13 +184,13 @@ if (__DEV__) {
         'is a no-op, but it indicates a memory leak in your application. To ' +
         'fix, cancel all subscriptions and asynchronous tasks in the ' +
         'componentWillUnmount method.%s',
-      getStackAddendumByWorkInProgressFiber(fiber),
+      ReactCurrentFiber.getStackByFiberInDevAndProd(fiber),
     );
     didWarnStateUpdateForUnmountedComponent[componentName] = true;
   };
 
   warnAboutInvalidUpdates = function(instance: React$Component<any>) {
-    switch (ReactDebugCurrentFiber.phase) {
+    switch (ReactCurrentFiber.phase) {
       case 'getChildContext':
         if (didWarnSetStateChildContext) {
           return;
@@ -363,7 +362,7 @@ function resetStack() {
 function commitAllHostEffects() {
   while (nextEffect !== null) {
     if (__DEV__) {
-      ReactDebugCurrentFiber.setCurrentFiber(nextEffect);
+      ReactCurrentFiber.setCurrentFiber(nextEffect);
     }
     recordEffect();
 
@@ -422,7 +421,7 @@ function commitAllHostEffects() {
   }
 
   if (__DEV__) {
-    ReactDebugCurrentFiber.resetCurrentFiber();
+    ReactCurrentFiber.resetCurrentFiber();
   }
 }
 
@@ -778,7 +777,7 @@ function completeUnitOfWork(workInProgress: Fiber): Fiber | null {
     // progress.
     const current = workInProgress.alternate;
     if (__DEV__) {
-      ReactDebugCurrentFiber.setCurrentFiber(workInProgress);
+      ReactCurrentFiber.setCurrentFiber(workInProgress);
     }
 
     const returnFiber = workInProgress.return;
@@ -794,7 +793,7 @@ function completeUnitOfWork(workInProgress: Fiber): Fiber | null {
       stopWorkTimer(workInProgress);
       resetExpirationTime(workInProgress, nextRenderExpirationTime);
       if (__DEV__) {
-        ReactDebugCurrentFiber.resetCurrentFiber();
+        ReactCurrentFiber.resetCurrentFiber();
       }
 
       if (next !== null) {
@@ -873,7 +872,7 @@ function completeUnitOfWork(workInProgress: Fiber): Fiber | null {
       }
 
       if (__DEV__) {
-        ReactDebugCurrentFiber.resetCurrentFiber();
+        ReactCurrentFiber.resetCurrentFiber();
       }
 
       if (next !== null) {
@@ -929,7 +928,7 @@ function performUnitOfWork(workInProgress: Fiber): Fiber | null {
   // See if beginning this work spawns more work.
   startWorkTimer(workInProgress);
   if (__DEV__) {
-    ReactDebugCurrentFiber.setCurrentFiber(workInProgress);
+    ReactCurrentFiber.setCurrentFiber(workInProgress);
   }
 
   if (__DEV__ && replayFailedUnitOfWorkWithInvokeGuardedCallback) {
@@ -957,7 +956,7 @@ function performUnitOfWork(workInProgress: Fiber): Fiber | null {
   }
 
   if (__DEV__) {
-    ReactDebugCurrentFiber.resetCurrentFiber();
+    ReactCurrentFiber.resetCurrentFiber();
     if (isReplayingFailedUnitOfWork) {
       // Currently replaying a failed unit of work. This should be unreachable,
       // because the render phase is meant to be idempotent, and it should
diff --git a/packages/react-reconciler/src/ReactStrictModeWarnings.js b/packages/react-reconciler/src/ReactStrictModeWarnings.js
index 365f4bf4d6..cd29d2de93 100644
--- a/packages/react-reconciler/src/ReactStrictModeWarnings.js
+++ b/packages/react-reconciler/src/ReactStrictModeWarnings.js
@@ -9,8 +9,9 @@
 
 import type {Fiber} from './ReactFiber';
 
+import {getStackByFiberInDevAndProd} from './ReactCurrentFiber';
+
 import getComponentName from 'shared/getComponentName';
-import {getStackAddendumByWorkInProgressFiber} from 'shared/ReactFiberComponentTreeHook';
 import {StrictMode} from './ReactTypeOfMode';
 import lowPriorityWarning from 'shared/lowPriorityWarning';
 import warning from 'shared/warning';
@@ -94,7 +95,7 @@ if (__DEV__) {
         });
 
         if (lifecyclesWarningMesages.length > 0) {
-          const strictRootComponentStack = getStackAddendumByWorkInProgressFiber(
+          const strictRootComponentStack = getStackByFiberInDevAndProd(
             strictRoot,
           );
 
@@ -341,7 +342,7 @@ if (__DEV__) {
         });
 
         const sortedNames = setToSortedString(uniqueNames);
-        const strictRootComponentStack = getStackAddendumByWorkInProgressFiber(
+        const strictRootComponentStack = getStackByFiberInDevAndProd(
           strictRoot,
         );
 
diff --git a/packages/shared/ReactFiberComponentTreeHook.js b/packages/shared/ReactFiberComponentTreeHook.js
deleted file mode 100644
index 8926ce3426..0000000000
--- a/packages/shared/ReactFiberComponentTreeHook.js
+++ /dev/null
@@ -1,54 +0,0 @@
-/**
- * Copyright (c) 2016-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 type {Fiber} from 'react-reconciler/src/ReactFiber';
-
-import {
-  IndeterminateComponent,
-  FunctionalComponent,
-  ClassComponent,
-  HostComponent,
-} from './ReactTypeOfWork';
-import describeComponentFrame from './describeComponentFrame';
-import getComponentName from './getComponentName';
-
-function describeFiber(fiber: Fiber): string {
-  switch (fiber.tag) {
-    case IndeterminateComponent:
-    case FunctionalComponent:
-    case ClassComponent:
-    case HostComponent:
-      const owner = fiber._debugOwner;
-      const source = fiber._debugSource;
-      const name = getComponentName(fiber);
-      let ownerName = null;
-      if (owner) {
-        ownerName = getComponentName(owner);
-      }
-      return describeComponentFrame(name, source, ownerName);
-    default:
-      return '';
-  }
-}
-
-// This function can only be called with a work-in-progress fiber and
-// only during begin or complete phase. Do not call it under any other
-// circumstances.
-export function getStackAddendumByWorkInProgressFiber(
-  workInProgress: Fiber,
-): string {
-  let info = '';
-  let node = workInProgress;
-  do {
-    info += describeFiber(node);
-    // Otherwise this return pointer might point to the wrong tree:
-    node = node.return;
-  } while (node);
-  return info;
-}