diff --git a/Cargo.lock b/Cargo.lock
index b651faac902..392f3e8e4bd 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2877,6 +2877,7 @@ dependencies = [
  "rustc_errors 0.0.0",
  "rustc_target 0.0.0",
  "serialize 0.0.0",
+ "smallvec 0.6.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "stable_deref_trait 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "syntax 0.0.0",
  "syntax_ext 0.0.0",