diff --git a/src/renderers/shared/ReactPerf.js b/src/renderers/shared/ReactPerf.js
index 95b92f1ac6..0f3886f69f 100644
--- a/src/renderers/shared/ReactPerf.js
+++ b/src/renderers/shared/ReactPerf.js
@@ -305,7 +305,7 @@ function getOperations(flushHistory = getLastMeasurements()) {
   return stats;
 }
 
-function printExclusive(flushHistory: FlushHistory) {
+function printExclusive(flushHistory?: FlushHistory) {
   if (!__DEV__) {
     warnInProduction();
     return;
@@ -331,7 +331,7 @@ function printExclusive(flushHistory: FlushHistory) {
   consoleTable(table);
 }
 
-function printInclusive(flushHistory: FlushHistory) {
+function printInclusive(flushHistory?: FlushHistory) {
   if (!__DEV__) {
     warnInProduction();
     return;
@@ -350,7 +350,7 @@ function printInclusive(flushHistory: FlushHistory) {
   consoleTable(table);
 }
 
-function printWasted(flushHistory: FlushHistory) {
+function printWasted(flushHistory?: FlushHistory) {
   if (!__DEV__) {
     warnInProduction();
     return;
@@ -369,7 +369,7 @@ function printWasted(flushHistory: FlushHistory) {
   consoleTable(table);
 }
 
-function printOperations(flushHistory: FlushHistory) {
+function printOperations(flushHistory?: FlushHistory) {
   if (!__DEV__) {
     warnInProduction();
     return;
diff --git a/src/shared/types/ReactPropTypeLocationNames.js b/src/shared/types/ReactPropTypeLocationNames.js
index 85e9851dca..1b36b04cc8 100644
--- a/src/shared/types/ReactPropTypeLocationNames.js
+++ b/src/shared/types/ReactPropTypeLocationNames.js
@@ -16,14 +16,14 @@ import type { ReactPropTypeLocations } from 'ReactPropTypeLocations';
 
 type NamesType = {[key: ReactPropTypeLocations]: string};
 
-var ReactPropTypeLocationNames = {};
+var ReactPropTypeLocationNames: NamesType = {};
 
 if (__DEV__) {
-  ReactPropTypeLocationNames = ({
+  ReactPropTypeLocationNames = {
     prop: 'prop',
     context: 'context',
     childContext: 'child context',
-  }: NamesType);
+  };
 }
 
 module.exports = ReactPropTypeLocationNames;