Add dev warning when type prop is missed for checkbox, radio or multi…

…ple select

src/Field.js

@@ -100,6 +100,24 @@ export default class Field extends React.Component<Props, State> {
     },
     onChange: (event: SyntheticInputEvent<*> | any) => {
       const { parse, value: _value } = this.props
+
+      if (process.env.NODE_ENV !== 'production' && event && event.target) {
+        const { type } = event.target
+        const props: Object = this.props
+        const unknown =
+          ~['checkbox', 'radio', 'select-multiple'].indexOf(type) && !props.type
+
+        warning(
+          !unknown,
+          `You must pass \`type={"${type}"}\` prop to your Field(${
+            props.name
+          }) component.\n` +
+            `Without it we don't know how to unpack your \`value\` prop - ${
+              props.value
+            }.`
+        )
+      }
+
       const value: any =
         event && event.target
           ? getValue(