From d951082b09b2027ca868720970ce2cb2bbc0c41d Mon Sep 17 00:00:00 2001
From: Sebastian McKenzie <sebmck@gmail.com>
Date: Mon, 29 Dec 2014 01:26:11 +1100
Subject: [PATCH] move replacement node comment inheritance to traverse
 replacement

---
 .../transformation/transformers/es6-modules.js     | 14 --------------
 lib/6to5/traverse/index.js                         | 13 ++++++++++++-
 2 files changed, 12 insertions(+), 15 deletions(-)

diff --git a/lib/6to5/transformation/transformers/es6-modules.js b/lib/6to5/transformation/transformers/es6-modules.js
index 039d716aa2..64bcbff63b 100644
--- a/lib/6to5/transformation/transformers/es6-modules.js
+++ b/lib/6to5/transformation/transformers/es6-modules.js
@@ -1,26 +1,16 @@
 var t = require("../../types");
 
-var inheritsComments = function (node, nodes) {
-  if (nodes.length) {
-    t.inheritsComments(nodes[0], node);
-  }
-};
-
 exports.ImportDeclaration = function (node, parent, file) {
   var nodes = [];
 
   if (node.specifiers.length) {
-    if (!file.moduleFormatter.importSpecifier) return;
     for (var i in node.specifiers) {
       file.moduleFormatter.importSpecifier(node.specifiers[i], node, nodes, parent);
     }
   } else {
-    if (!file.moduleFormatter.importDeclaration) return;
     file.moduleFormatter.importDeclaration(node, nodes, parent);
   }
 
-  inheritsComments(node, nodes);
-
   return nodes;
 };
 
@@ -35,16 +25,12 @@ exports.ExportDeclaration = function (node, parent, file) {
       declar.init = declar.init || t.identifier("undefined");
     }
 
-    if (!file.moduleFormatter.exportDeclaration) return;
     file.moduleFormatter.exportDeclaration(node, nodes, parent);
   } else {
-    if (!file.moduleFormatter.exportSpecifier) return;
     for (var i in node.specifiers) {
       file.moduleFormatter.exportSpecifier(node.specifiers[i], node, nodes, parent);
     }
   }
 
-  inheritsComments(node, nodes);
-
   return nodes;
 };
diff --git a/lib/6to5/traverse/index.js b/lib/6to5/traverse/index.js
index bc85ed7248..02ce4b4465 100644
--- a/lib/6to5/traverse/index.js
+++ b/lib/6to5/traverse/index.js
@@ -42,9 +42,20 @@ function traverse(parent, opts, scope) {
 
         if (result != null) {
           updated = true;
+
+          var isArray = _.isArray(result);
+
+          // inherit comments from original node to the first replacement node
+          var inheritTo = result;
+          if (isArray) inheritTo = result[0];
+          t.inheritsComments(inheritTo, node);
+
+          // replace the node
           node = obj[key] = result;
 
-          if (_.isArray(result) && _.contains(t.STATEMENT_OR_BLOCK_KEYS, key) && !t.isBlockStatement(obj)) {
+          // we're replacing a statement or block node with an array of statements so we better
+          // ensure that it's a block
+          if (isArray && _.contains(t.STATEMENT_OR_BLOCK_KEYS, key) && !t.isBlockStatement(obj)) {
             t.ensureBlock(obj, key);
           }
         }