Add location to propTypeRequiredWrapper error message.

src/utils/propTypeRequiredWrapper.js

@@ -1,11 +1,16 @@
 const checkRequiredThenValidate = (validator) =>
-    (props, propName, componentName, ...rest) =>
+    (props, propName, componentName, location) =>
 {
     if (props[propName] !== null) {
-        return validator(props, propName, componentName, ...rest);
+        return validator(props, propName, componentName, location);
     }
+
+    /* global ReactPropTypesLocationNames */ // Pacify ESLint
+    const location_name = ReactPropTypesLocationNames[location];
+
     return new Error(
-        `Missing prop \`${propName}\` not supplied to \`${componentName}\``
+        `Required prop \`${propName}\` was not specified in ` +
+        `\`${componentName}\`. Check the render method of \`${location_name}\`.`
     );
 };