diff --git a/src/babel/transformation/helpers/name-method.js b/src/babel/transformation/helpers/name-method.js
index 6c0b78dca7..8d3c7693d9 100644
--- a/src/babel/transformation/helpers/name-method.js
+++ b/src/babel/transformation/helpers/name-method.js
@@ -99,6 +99,7 @@ export function property(node, file, scope) {
   if (!t.isLiteral(key)) return node; // we can't set a function id with this
 
   var name = t.toIdentifier(key.value);
+  if (name === "eval" || name === "arguments") name = "_" + name;
   var id = t.identifier(name);
 
   var method = node.value;
diff --git a/src/babel/types/validators.js b/src/babel/types/validators.js
index 9fb1403c5b..2c57deac1d 100644
--- a/src/babel/types/validators.js
+++ b/src/babel/types/validators.js
@@ -115,9 +115,7 @@ export function isReferencedIdentifier(node: Object, parent: Object, opts?: Obje
  */
 
 export function isValidIdentifier(name: string): boolean {
-  if (!isString(name)) return false;
-  if (esutils.keyword.isReservedWordES6(name, true)) return false;
-  if (name === "eval" || name === "arguments") return false;
+  if (!isString(name) || esutils.keyword.isReservedWordES6(name, true)) return false;
   return esutils.keyword.isIdentifierNameES6(name);
 }