fix immutable support in lose mode

src/handleSubmit.js

@@ -3,6 +3,7 @@ import isPromise from 'is-promise'
 import type { SubmitFunction } from './types'
 import type { Props } from './createReduxForm'
 import SubmissionError from './SubmissionError'
+import { List } from 'immutable'
 
 const isSubmissionError = error => error && error.name === SubmissionError.name
 
@@ -11,9 +12,14 @@ const mergeErrors = ({ asyncErrors, syncErrors }) =>
     ? asyncErrors.merge(syncErrors).toJS()
     : { ...asyncErrors, ...syncErrors }
 
+// fields may be an Immutable List which cannot be spread
+// convert the fields to an array if necessary
+const makeFieldsArray = (fields: string[] | List<string>) =>
+  List.isList(fields) ? ((fields: any): List<string>).toArray() : fields
+
 const executeSubmit = (
   submit: SubmitFunction,
-  fields: string[],
+  fields: string[] | List<string>,
   props: Props
 ) => {
   const {
@@ -28,6 +34,8 @@ const executeSubmit = (
     values
   } = props
 
+  fields = makeFieldsArray(fields)
+
   let result
   try {
     result = submit(values, dispatch, props)
@@ -96,7 +104,7 @@ const handleSubmit = (
   props: Props,
   valid: boolean,
   asyncValidate: Function,
-  fields: string[]
+  fields: string[] | List<string>
 ) => {
   const {
     dispatch,
@@ -108,7 +116,9 @@ const handleSubmit = (
     persistentSubmitErrors
   } = props
 
-  touch(...Array.from(fields)) // mark all fields as touched
+  fields = makeFieldsArray(fields)
+
+  touch(...fields) // mark all fields as touched
 
   if (valid || persistentSubmitErrors) {
     const asyncValidateResult = asyncValidate && asyncValidate()