diff --git a/src/renderers/shared/fiber/ReactFiberContext.js b/src/renderers/shared/fiber/ReactFiberContext.js
index a94ebf77e8..f29b96378a 100644
--- a/src/renderers/shared/fiber/ReactFiberContext.js
+++ b/src/renderers/shared/fiber/ReactFiberContext.js
@@ -35,6 +35,7 @@ const {
 if (__DEV__) {
   var checkReactTypeSpec = require('checkReactTypeSpec');
   var ReactDebugCurrentFrame = require('ReactDebugCurrentFrame');
+  var ReactDebugLifeCycle = require('ReactDebugLifeCycle');
   var warnedAboutMissingGetChildContext = {};
 }
 
@@ -47,21 +48,6 @@ let didPerformWorkStackCursor : StackCursor<boolean> = createCursor(false);
 // pushed the next context provider, and now need to merge their contexts.
 let previousContext : Object = emptyObject;
 
-if (__DEV__) {
-  var _isProcessingChildContext = false;
-  var onBeginProcessingChildContext = function() {
-    _isProcessingChildContext = true;
-  };
-  exports.onBeginProcessingChildContext = onBeginProcessingChildContext;
-  var onEndProcessingChildContext = function() {
-    _isProcessingChildContext = false;
-  };
-  exports.onEndProcessingChildContext = onEndProcessingChildContext;
-  exports.isProcessingChildContext = function() : boolean {
-    return _isProcessingChildContext;
-  };
-}
-
 function getUnmaskedContext(workInProgress : Fiber) : Object {
   const hasOwnContext = isContextProvider(workInProgress);
   if (hasOwnContext) {
@@ -159,10 +145,6 @@ exports.pushTopLevelContextObject = function(fiber : Fiber, context : Object, di
 };
 
 function processChildContext(fiber : Fiber, parentContext : Object, isReconciling : boolean): Object {
-  if (__DEV__) {
-    onBeginProcessingChildContext();
-  }
-
   const instance = fiber.stateNode;
   const childContextTypes = fiber.type.childContextTypes;
 
@@ -187,7 +169,16 @@ function processChildContext(fiber : Fiber, parentContext : Object, isReconcilin
     return parentContext;
   }
 
-  const childContext = instance.getChildContext();
+  let childContext;
+  if (__DEV__) {
+    ReactDebugLifeCycle.current = fiber;
+    ReactDebugLifeCycle.phase = 'getChildContext';
+    childContext = instance.getChildContext();
+    ReactDebugLifeCycle.current = null;
+    ReactDebugLifeCycle.phase = null;
+  } else {
+    childContext = instance.getChildContext();
+  }
   for (let contextKey in childContext) {
     invariant(
       contextKey in childContextTypes,
@@ -209,10 +200,6 @@ function processChildContext(fiber : Fiber, parentContext : Object, isReconcilin
     ReactDebugCurrentFrame.current = null;
   }
 
-  if (__DEV__) {
-    onEndProcessingChildContext();
-  }
-
   return {...parentContext, ...childContext};
 }
 exports.processChildContext = processChildContext;
diff --git a/src/renderers/shared/fiber/ReactFiberScheduler.js b/src/renderers/shared/fiber/ReactFiberScheduler.js
index d90dedcb0d..08f08c9fe5 100644
--- a/src/renderers/shared/fiber/ReactFiberScheduler.js
+++ b/src/renderers/shared/fiber/ReactFiberScheduler.js
@@ -91,10 +91,6 @@ if (__DEV__) {
   var ReactFiberInstrumentation = require('ReactFiberInstrumentation');
   var ReactDebugCurrentFiber = require('ReactDebugCurrentFiber');
   var ReactDebugLifeCycle = require('ReactDebugLifeCycle');
-  var {
-    isProcessingChildContext,
-    onEndProcessingChildContext,
-  } = require('ReactFiberContext');
 
   var warnAboutUpdateOnUnmounted = function(instance : ReactClass<any>) {
     const ctor = instance.constructor;
@@ -109,19 +105,22 @@ if (__DEV__) {
   };
 
   var warnAboutInvalidUpdates = function(instance : ReactClass<any>) {
-    if (isProcessingChildContext()) {
-      warning(
-        false,
-        'setState(...): Cannot call setState() inside getChildContext()',
-      );
-    } else if (ReactDebugLifeCycle.phase === 'render') {
-      warning(
-        false,
-        'Cannot update during an existing state transition (such as within ' +
-        '`render` or another component\'s constructor). Render methods should ' +
-        'be a pure function of props and state; constructor side-effects are ' +
-        'an anti-pattern, but can be moved to `componentWillMount`.'
-      );
+    switch (ReactDebugLifeCycle.phase) {
+      case 'getChildContext':
+        warning(
+          false,
+          'setState(...): Cannot call setState() inside getChildContext()',
+        );
+        break;
+      case 'render':
+        warning(
+          false,
+          'Cannot update during an existing state transition (such as within ' +
+          '`render` or another component\'s constructor). Render methods should ' +
+          'be a pure function of props and state; constructor side-effects are ' +
+          'an anti-pattern, but can be moved to `componentWillMount`.'
+        );
+        break;
     }
   };
 }
@@ -883,7 +882,6 @@ module.exports = function<T, P, I, TI, PI, C, CX, PL>(config : HostConfig<T, P,
       ReactDebugCurrentFiber.current = null;
       ReactDebugLifeCycle.current = null;
       ReactDebugLifeCycle.phase = null;
-      onEndProcessingChildContext();
     }
     // It is no longer valid because this unit of work failed.
     nextUnitOfWork = null;
diff --git a/src/renderers/shared/fiber/isomorphic/ReactDebugLifeCycle.js b/src/renderers/shared/fiber/isomorphic/ReactDebugLifeCycle.js
index afe0dc3fef..3e74494e93 100644
--- a/src/renderers/shared/fiber/isomorphic/ReactDebugLifeCycle.js
+++ b/src/renderers/shared/fiber/isomorphic/ReactDebugLifeCycle.js
@@ -14,7 +14,7 @@
 
 import type { Fiber } from 'ReactFiber';
 
-type LifeCyclePhase = 'render';
+type LifeCyclePhase = 'render' | 'getChildContext';
 
 const ReactDebugLifeCycle = {
   current: (null : Fiber | null),