From a80945cfb4199e998efbe3432ceba184ec90a403 Mon Sep 17 00:00:00 2001
From: Sebastian McKenzie <sebmck@gmail.com>
Date: Sun, 18 Jan 2015 21:33:22 +1100
Subject: [PATCH] ignore function declarations in TDZ detection

---
 .../transformation/transformers/es6-let-scoping.js   | 12 +++++++-----
 .../transformers/spec-block-scoped-functions.js      |  3 +++
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/lib/6to5/transformation/transformers/es6-let-scoping.js b/lib/6to5/transformation/transformers/es6-let-scoping.js
index d48e3fcf74..ebff0352b3 100644
--- a/lib/6to5/transformation/transformers/es6-let-scoping.js
+++ b/lib/6to5/transformation/transformers/es6-let-scoping.js
@@ -130,16 +130,18 @@ LetScoping.prototype.checkTDZ = function () {
       // declared node is different in this scope
       if (scope.get(node.name, true) !== declared) return;
 
-      var declaredLoc  = declared.loc.start;
-      var referenceLoc = node.loc.start;
+      var declaredLoc  = declared.loc;
+      var referenceLoc = node.loc;
+
+      if (!declaredLoc || !referenceLoc) return;
 
       // does this reference appear on a line before the declaration?
-      var before = referenceLoc.line < declaredLoc.line;
+      var before = referenceLoc.start.line < declaredLoc.start.line;
 
-      if (referenceLoc.line === declaredLoc.line) {
+      if (referenceLoc.start.line === declaredLoc.start.line) {
         // this reference appears on the same line
         // check it appears before the declaration
-        before = referenceLoc.col < declaredLoc.col;
+        before = referenceLoc.start.col < declaredLoc.start.col;
       }
 
       if (before) {
diff --git a/lib/6to5/transformation/transformers/spec-block-scoped-functions.js b/lib/6to5/transformation/transformers/spec-block-scoped-functions.js
index 3d8d3449c8..087b881d9f 100644
--- a/lib/6to5/transformation/transformers/spec-block-scoped-functions.js
+++ b/lib/6to5/transformation/transformers/spec-block-scoped-functions.js
@@ -7,6 +7,9 @@ exports.FunctionDeclaration = function (node, parent) {
     return;
   }
 
+  // this is to avoid triggering the TDZ detection
+  node.id.loc = null;
+
   var declar = t.variableDeclaration("let", [
     t.variableDeclarator(node.id, t.toExpression(node))
   ]);