From c0299320f0169d0e5937fef244e4bacf9c3f0374 Mon Sep 17 00:00:00 2001
From: Sebastian McKenzie <sebmck@gmail.com>
Date: Sat, 31 Jan 2015 21:27:20 +1100
Subject: [PATCH] avoid transforming of inner labels and propagation of maps in
 block scoping transformer - #644

---
 .../transformers/es6/block-scoping.js         | 21 +++++++++++++++++--
 .../es6-block-scoping-exec/nested-labels-4.js | 14 +++++++++++++
 .../es6-let-scoping/.switch-break/exec.js     | 11 ----------
 3 files changed, 33 insertions(+), 13 deletions(-)
 create mode 100644 test/fixtures/transformation/es6-block-scoping-exec/nested-labels-4.js
 delete mode 100644 test/fixtures/transformation/es6-let-scoping/.switch-break/exec.js

diff --git a/lib/6to5/transformation/transformers/es6/block-scoping.js b/lib/6to5/transformation/transformers/es6/block-scoping.js
index 2fb6c02cad..6ccc69ddc3 100644
--- a/lib/6to5/transformation/transformers/es6/block-scoping.js
+++ b/lib/6to5/transformation/transformers/es6/block-scoping.js
@@ -311,9 +311,9 @@ var loopVisitor = {
     var replace;
 
     if (t.isLoop(node)) {
-      state = clone(state);
       state.ignoreLabeless = true;
       traverse(node, loopVisitor, scope, state);
+      state.ignoreLabeless = false;
     }
 
     if (t.isFunction(node) || t.isLoop(node)) {
@@ -324,9 +324,15 @@ var loopVisitor = {
 
     if (loopText) {
       if (node.label) {
+        // we shouldn't be transforming this because it exists somewhere inside
+        if (state.innerLabels.indexOf(node.label.name) >= 0) {
+          return;
+        }
+
         loopText = loopText + "|" + node.label.name;
       } else {
-        // we shouldn't be dealing with this
+        // we shouldn't be transforming these statements because
+        // they don't refer to the actual loop we're scopifying
         if (state.ignoreLabeless) return;
 
         // break statements mean something different in this context
@@ -352,6 +358,14 @@ var loopVisitor = {
   }
 };
 
+var loopLabelVisitor = {
+  enter: function (node, parent, scope, context, state) {
+    if (t.isLabeledStatement(node)) {
+      state.innerLabels.push(node.label.name);
+    }
+  }
+};
+
 /**
  * If we're inside of a loop then traverse it and check if it has one of
  * the following node types `ReturnStatement`, `BreakStatement`,
@@ -365,12 +379,15 @@ LetScoping.prototype.checkLoop = function () {
   var state = {
     hasBreakContinue: false,
     ignoreLabeless:   false,
+    innerLabels:      [],
     hasReturn:        false,
     isLoop:           !!this.loopParent,
     map:              {}
   };
 
+  traverse(this.block, loopLabelVisitor, this.scope, state);
   traverse(this.block, loopVisitor, this.scope, state);
+
   return state;
 };
 
diff --git a/test/fixtures/transformation/es6-block-scoping-exec/nested-labels-4.js b/test/fixtures/transformation/es6-block-scoping-exec/nested-labels-4.js
new file mode 100644
index 0000000000..f6a7fa54f1
--- /dev/null
+++ b/test/fixtures/transformation/es6-block-scoping-exec/nested-labels-4.js
@@ -0,0 +1,14 @@
+(function () {
+  var stack = [];
+
+  loop1:
+  for (let j = 0; j < 10; j++) {
+    for (let i = 0; i < 10; i++) {
+      stack.push(() => [i, j]);
+      break loop1;
+    }
+  }
+
+  assert.deepEqual(stack.length, 1);
+  assert.deepEqual(stack[0](), [0, 0]);
+})();
diff --git a/test/fixtures/transformation/es6-let-scoping/.switch-break/exec.js b/test/fixtures/transformation/es6-let-scoping/.switch-break/exec.js
deleted file mode 100644
index 0e7eb1fb2f..0000000000
--- a/test/fixtures/transformation/es6-let-scoping/.switch-break/exec.js
+++ /dev/null
@@ -1,11 +0,0 @@
-if (true) {
-  const x = 1;
-  switch (x) {
-    case 1: {
-      function y() {
-        assert(x, 1);
-      };
-      break;
-    }
-  }
-}