Ensure no strict-mode issues when referencing arguments.

Fixes #28

Author: leebyron

index.js

@@ -200,6 +200,7 @@ var asyncToGenVisitor = {
         var envRecord = currentScope(ast);
         if (envRecord.async) {
           envRecord.referencesArgs = true;
+          editor.overwrite(node.start, node.end, 'argument$');
         }
       }
     }
@@ -335,7 +336,7 @@ function createAsyncWrapping(node) {
   }
 
   if (node.referencesArgs) {
-    argNames.push('arguments');
+    argNames.push('argument$');
     argValues.push('arguments');
   }
 

test/expected.js

@@ -132,13 +132,13 @@ function normalThis() {
 }
 
 // async function referencing arguments
-function asyncThis() {return __async(function*(arguments){
-  return arguments;
+function asyncThis() {return __async(function*(argument$){
+  return argument$;
 }(arguments))}
 
 // async arrow function referencing arguments
-function within1() {return __async(function*(arguments){
-  () => () =>__async(function*(arguments){ return arguments}(arguments))
+function within1() {return __async(function*(argument$){
+  () => () =>__async(function*(argument$){ return argument$}(arguments))
 }(arguments))}