diff --git a/src/renderers/shared/fiber/ReactChildFiber.js b/src/renderers/shared/fiber/ReactChildFiber.js
index 3cb1cad24762e..3587750b2384e 100644
--- a/src/renderers/shared/fiber/ReactChildFiber.js
+++ b/src/renderers/shared/fiber/ReactChildFiber.js
@@ -59,7 +59,7 @@ 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(child) || '');
+      (getCurrentFiberStackAddendum() || '');
     if (ownerHasKeyUseWarning[currentComponentErrorInfo]) {
       return;
     }
@@ -70,7 +70,7 @@ 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(child),
+      getCurrentFiberStackAddendum(),
     );
   };
 }
diff --git a/src/renderers/shared/fiber/ReactFiberErrorLogger.js b/src/renderers/shared/fiber/ReactFiberErrorLogger.js
index 007be1a8b6186..9289f00a751a8 100644
--- a/src/renderers/shared/fiber/ReactFiberErrorLogger.js
+++ b/src/renderers/shared/fiber/ReactFiberErrorLogger.js
@@ -16,7 +16,7 @@ const invariant = require('fbjs/lib/invariant');
 
 import type {CapturedError} from 'ReactFiberScheduler';
 
-const defaultShowDialog = () => true;
+const defaultShowDialog = (capturedError: CapturedError) => true;
 
 let showDialog = defaultShowDialog;
 
diff --git a/src/renderers/shared/fiber/ReactFiberReconciler.js b/src/renderers/shared/fiber/ReactFiberReconciler.js
index 14426385a0152..4ba62b675716a 100644
--- a/src/renderers/shared/fiber/ReactFiberReconciler.js
+++ b/src/renderers/shared/fiber/ReactFiberReconciler.js
@@ -49,7 +49,7 @@ type OpaqueRoot = FiberRoot;
 
 export type HostConfig<T, P, I, TI, PI, C, CX, PL> = {
   getRootHostContext(rootContainerInstance: C): CX,
-  getChildHostContext(parentHostContext: CX, type: T): CX,
+  getChildHostContext(parentHostContext: CX, type: T, instance: C): CX,
   getPublicInstance(instance: I | TI): PI,
 
   createInstance(
diff --git a/src/renderers/shared/fiber/ReactFiberScheduler.js b/src/renderers/shared/fiber/ReactFiberScheduler.js
index 71e9aca36ac67..279ea3448a7ef 100644
--- a/src/renderers/shared/fiber/ReactFiberScheduler.js
+++ b/src/renderers/shared/fiber/ReactFiberScheduler.js
@@ -462,7 +462,7 @@ module.exports = function<T, P, I, TI, PI, C, CX, PL>(
       firstEffect = finishedWork.firstEffect;
     }
 
-    const commitInfo = prepareForCommit();
+    prepareForCommit();
 
     // Commit all the side-effects within a tree. We'll do this in two passes.
     // The first pass performs all the host insertions, updates, deletions and
@@ -474,15 +474,10 @@ module.exports = function<T, P, I, TI, PI, C, CX, PL>(
     while (nextEffect !== null) {
       let error = null;
       if (__DEV__) {
-        error = invokeGuardedCallback(
-          null,
-          commitAllHostEffects,
-          null,
-          finishedWork,
-        );
+        error = invokeGuardedCallback(null, commitAllHostEffects, null);
       } else {
         try {
-          commitAllHostEffects(finishedWork);
+          commitAllHostEffects();
         } catch (e) {
           error = e;
         }
@@ -504,7 +499,7 @@ module.exports = function<T, P, I, TI, PI, C, CX, PL>(
       stopCommitHostEffectsTimer();
     }
 
-    resetAfterCommit(commitInfo);
+    resetAfterCommit();
 
     // The work-in-progress tree is now the current tree. This must come after
     // the first pass of the commit phase, so that the previous tree is still
@@ -523,15 +518,10 @@ module.exports = function<T, P, I, TI, PI, C, CX, PL>(
     while (nextEffect !== null) {
       let error = null;
       if (__DEV__) {
-        error = invokeGuardedCallback(
-          null,
-          commitAllLifeCycles,
-          null,
-          finishedWork,
-        );
+        error = invokeGuardedCallback(null, commitAllLifeCycles, null);
       } else {
         try {
-          commitAllLifeCycles(finishedWork);
+          commitAllLifeCycles();
         } catch (e) {
           error = e;
         }
diff --git a/src/renderers/shared/stack/reconciler/CallbackQueue.js b/src/renderers/shared/stack/reconciler/CallbackQueue.js
index c82dbfccd974f..0362598ac1e6a 100644
--- a/src/renderers/shared/stack/reconciler/CallbackQueue.js
+++ b/src/renderers/shared/stack/reconciler/CallbackQueue.js
@@ -28,10 +28,10 @@ var validateCallback = require('validateCallback');
  * @implements PooledClass
  * @internal
  */
-class CallbackQueue<T> {
-  _callbacks: ?Array<() => void>;
+class CallbackQueue<T, Targ> {
+  _callbacks: ?Array<(arg: Targ) => void>;
   _contexts: ?Array<T>;
-  _arg: ?mixed;
+  _arg: Targ;
 
   constructor(arg) {
     this._callbacks = null;
diff --git a/src/shared/utils/PooledClass.js b/src/shared/utils/PooledClass.js
index a89b9e1a7f425..7b5d93ab737bd 100644
--- a/src/shared/utils/PooledClass.js
+++ b/src/shared/utils/PooledClass.js
@@ -95,8 +95,10 @@ var addPoolingTo = function<T>(
   CopyConstructor: Class<T>,
   pooler: Pooler,
 ): Class<T> & {
-  getPooled(): /* arguments of the constructor */ T,
-  release(): void,
+  getPooled(
+    ...args: $ReadOnlyArray<mixed>
+  ): /* arguments of the constructor */ T,
+  release(instance: mixed): void,
 } {
   // Casting as any so that flow ignores the actual implementation and trusts
   // it to match the type we declared