diff --git a/Cargo.lock b/Cargo.lock
index 9119af126672754335d30038f557dc13b231e203..71ea6f242b13fef3f6983d7a4a34b337e7d6c24e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3393,6 +3393,7 @@ dependencies = [
  "serde",
  "serde_json",
  "smallvec",
+ "syn 0.15.35",
  "url 2.1.0",
  "winapi 0.3.6",
 ]
diff --git a/src/tools/rustc-workspace-hack/Cargo.toml b/src/tools/rustc-workspace-hack/Cargo.toml
index a78cbdc2c4c6afb0fa31909496d0a1db949521b1..285af038a1ef45438ae0c14961d59fe286f6e58c 100644
--- a/src/tools/rustc-workspace-hack/Cargo.toml
+++ b/src/tools/rustc-workspace-hack/Cargo.toml
@@ -64,7 +64,7 @@ serde = { version = "1.0.82", features = ['derive'] }
 serde_json = { version = "1.0.31", features = ["raw_value"] }
 smallvec = { version = "0.6", features = ['union', 'may_dangle'] }
 url = { version = "2.0", features = ['serde'] }
-
+syn = { version = "0.15", features = ['full'] }
 
 [target.'cfg(not(windows))'.dependencies]
 openssl = { version = "0.10.12", optional = true }