diff --git a/lib/6to5/traversal/scope.js b/lib/6to5/traversal/scope.js
index 489c758b73..06e878382e 100644
--- a/lib/6to5/traversal/scope.js
+++ b/lib/6to5/traversal/scope.js
@@ -320,11 +320,12 @@ Scope.prototype.crawl = function () {
     for (i = 0; i < block.params.length; i++) {
       this.register(block.params[i]);
     }
+    this.traverse(block.body, blockVariableVisitor, this);
   }
 
   // Program, BlockStatement, Function - let variables
 
-  if (t.isBlockStatement(block) || t.isProgram(block) || t.isFunction(block)) {
+  if (t.isBlockStatement(block) || t.isProgram(block)) {
     this.traverse(block, blockVariableVisitor, this);
   }