From db28c18458ef8f62e80d9cc9ddbeb2be0a943a92 Mon Sep 17 00:00:00 2001
From: Logan Smyth <loganfsmyth@gmail.com>
Date: Wed, 22 Nov 2017 18:23:28 -0800
Subject: [PATCH] Disallow nested '.env' blocks since they are useless.

---
 packages/babel-core/src/config/options.js | 3 +++
 packages/babel-core/test/api.js           | 8 --------
 2 files changed, 3 insertions(+), 8 deletions(-)

diff --git a/packages/babel-core/src/config/options.js b/packages/babel-core/src/config/options.js
index 5ca278b14b..450f52b8e8 100644
--- a/packages/babel-core/src/config/options.js
+++ b/packages/babel-core/src/config/options.js
@@ -206,6 +206,9 @@ export function validate(type: OptionsType, opts: {}): ValidatedOptions {
     if (type !== "arguments" && ROOT_VALIDATORS[key]) {
       throw new Error(`.${key} is only allowed in root programmatic options`);
     }
+    if (type === "env" && key === "env") {
+      throw new Error(`.${key} is not allowed inside another env block`);
+    }
 
     const validator =
       COMMON_VALIDATORS[key] ||
diff --git a/packages/babel-core/test/api.js b/packages/babel-core/test/api.js
index cad0308862..215a8960f1 100644
--- a/packages/babel-core/test/api.js
+++ b/packages/babel-core/test/api.js
@@ -296,12 +296,6 @@ describe("api", function() {
         development: {
           passPerPreset: true,
           presets: [pushPreset("argthree"), pushPreset("argfour")],
-          env: {
-            development: {
-              passPerPreset: true,
-              presets: [pushPreset("argfive"), pushPreset("argsix")],
-            },
-          },
         },
       },
     });
@@ -327,8 +321,6 @@ describe("api", function() {
         "fourteen;",
         "fifteen;",
         "sixteen;",
-        "argfive;",
-        "argsix;",
         "argthree;",
         "argfour;",
         "seven;",