assorted minor cleanup of variables

src/babel/transformation/transformers/es6/block-scoping.js

@@ -465,14 +465,14 @@ class BlockScoping {
     var declar;
 
     //
-    for (var i = 0; i < declarators.length; i++) {
+    for (let i = 0; i < declarators.length; i++) {
       declar = declarators[i];
       extend(this.outsideLetReferences, t.getBindingIdentifiers(declar));
     }
 
     //
     if (block.body) {
-      for (i = 0; i < block.body.length; i++) {
+      for (let i = 0; i < block.body.length; i++) {
         declar = block.body[i];
         if (isLet(declar, block)) {
           declarators = declarators.concat(declar.declarations);
@@ -481,7 +481,7 @@ class BlockScoping {
     }
 
     //
-    for (i = 0; i < declarators.length; i++) {
+    for (let i = 0; i < declarators.length; i++) {
       declar = declarators[i];
       var keys = t.getBindingIdentifiers(declar);
       extend(this.letReferences, keys);

src/babel/transformation/transformers/optimisation/react.constant-elements.js

@@ -29,14 +29,11 @@ var immutabilityVisitor = {
 };
 
 export function JSXElement(node, parent, scope, file) {
-  if (node._ignoreConstant) return;
+  if (node._hoisted) return;
 
   var state = { isImmutable: true };
   this.traverse(immutabilityVisitor, state);
   this.skip();
 
-  if (state.isImmutable) {
-    this.hoist();
-    node._ignoreConstant = true;
-  }
+  if (state.isImmutable) this.hoist();
 }

src/babel/traversal/path/hoister.js

@@ -19,7 +19,6 @@ var referenceVisitor = {
         if (bindingInfo && bindingInfo.constant) {
           state.bindings[node.name] = bindingInfo;
         } else {
-          scope.dump();
           state.foundIncompatible = true;
           this.stop();
         }
@@ -90,6 +89,10 @@ export default class PathHoister {
   }
 
   run() {
+    var node = this.path.node;
+    if (node._hoisted) return;
+    this.path._hoisted = true;
+
     this.path.traverse(referenceVisitor, this);
     if (this.foundIncompatible) return;