diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3f205ca1f3..4c7f7ef26b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+# 1.14.6
+
+ * Avoid ensuring a block on non-array node replacements.
+
 # 1.14.5
 
  * Upgrade `acorn-6to5`.
diff --git a/bin/_6to5-node b/bin/_6to5-node
index 62d30b0512..2133bf156e 100644
--- a/bin/_6to5-node
+++ b/bin/_6to5-node
@@ -32,6 +32,7 @@ to5.register({
 
 var _eval = function (code, filename) {
   code = to5.transform(code, {
+    modules: "commonInterop",
     filename: filename,
     blacklist: ["useStrict"],
     experimental: commander.experimental
diff --git a/lib/6to5/traverse/index.js b/lib/6to5/traverse/index.js
index 76ae72e24e..32bad31add 100644
--- a/lib/6to5/traverse/index.js
+++ b/lib/6to5/traverse/index.js
@@ -51,7 +51,7 @@ function traverse(parent, callbacks, opts) {
           updated = true;
           node = obj[key] = result;
 
-          if (_.contains(t.STATEMENT_OR_BLOCK_KEYS, key) && !t.isBlockStatement(obj)) {
+          if (_.isArray(result) && _.contains(t.STATEMENT_OR_BLOCK_KEYS, key) && !t.isBlockStatement(obj)) {
             t.ensureBlock(obj, key);
           }
         }