diff --git a/src/librustc_borrowck/borrowck/mod.rs b/src/librustc_borrowck/borrowck/mod.rs
index 7dca47485bb..669fb9103aa 100644
--- a/src/librustc_borrowck/borrowck/mod.rs
+++ b/src/librustc_borrowck/borrowck/mod.rs
@@ -1487,7 +1487,7 @@ impl DataFlowOperator for LoanDataFlowOperator {
     }
 }
 
-impl<'tcx> fmt::Debug for InteriorKind {
+impl fmt::Debug for InteriorKind {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
             InteriorField(mc::FieldIndex(_, info)) => write!(f, "{}", info),
diff --git a/src/librustc_borrowck/lib.rs b/src/librustc_borrowck/lib.rs
index 14bc77f380a..5d8b0cd14dd 100644
--- a/src/librustc_borrowck/lib.rs
+++ b/src/librustc_borrowck/lib.rs
@@ -3,6 +3,7 @@
 #![allow(non_camel_case_types)]
 #![deny(rust_2018_idioms)]
 #![deny(internal)]
+#![deny(unused_lifetimes)]
 
 #![feature(nll)]