diff --git a/src/bootstrap/bin/main.rs b/src/bootstrap/bin/main.rs
index da35c971f97..bd1a87c5744 100644
--- a/src/bootstrap/bin/main.rs
+++ b/src/bootstrap/bin/main.rs
@@ -6,7 +6,7 @@
 //! directory in each respective module.
 
 // NO-RUSTC-WRAPPER
-#![deny(warnings, rust_2018_idioms)]
+#![deny(warnings, rust_2018_idioms, unused_lifetimes)]
 
 use std::env;
 
diff --git a/src/bootstrap/bin/rustc.rs b/src/bootstrap/bin/rustc.rs
index 3888d0ef627..2e9044a8150 100644
--- a/src/bootstrap/bin/rustc.rs
+++ b/src/bootstrap/bin/rustc.rs
@@ -16,7 +16,7 @@
 //! never get replaced.
 
 // NO-RUSTC-WRAPPER
-#![deny(warnings, rust_2018_idioms)]
+#![deny(warnings, rust_2018_idioms, unused_lifetimes)]
 
 use std::env;
 use std::ffi::OsString;
@@ -129,6 +129,7 @@ fn main() {
        env::var_os("RUSTC_EXTERNAL_TOOL").is_none() {
         cmd.arg("-Dwarnings");
         cmd.arg("-Drust_2018_idioms");
+        cmd.arg("-Dunused_lifetimes");
         // cfg(not(bootstrap)): Remove this during the next stage 0 compiler update.
         // `-Drustc::internal` is a new feature and `rustc_version` mis-reports the `stage`.
         let cfg_not_bootstrap = stage != "0" && crate_name != Some("rustc_version");
diff --git a/src/bootstrap/bin/rustdoc.rs b/src/bootstrap/bin/rustdoc.rs
index 057daaf2dc4..ff38ee8788f 100644
--- a/src/bootstrap/bin/rustdoc.rs
+++ b/src/bootstrap/bin/rustdoc.rs
@@ -3,7 +3,7 @@
 //! See comments in `src/bootstrap/rustc.rs` for more information.
 
 // NO-RUSTC-WRAPPER
-#![deny(warnings, rust_2018_idioms)]
+#![deny(warnings, rust_2018_idioms, unused_lifetimes)]
 
 use std::env;
 use std::process::Command;
diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs
index 0f7e4f6e977..c2e64ef51a7 100644
--- a/src/bootstrap/lib.rs
+++ b/src/bootstrap/lib.rs
@@ -104,7 +104,7 @@
 //! also check out the `src/bootstrap/README.md` file for more information.
 
 // NO-RUSTC-WRAPPER
-#![deny(warnings, rust_2018_idioms)]
+#![deny(warnings, rust_2018_idioms, unused_lifetimes)]
 
 #![feature(core_intrinsics)]
 #![feature(drain_filter)]
@@ -1313,7 +1313,7 @@ fn chmod(path: &Path, perms: u32) {
 fn chmod(_path: &Path, _perms: u32) {}
 
 
-impl<'a> Compiler {
+impl Compiler {
     pub fn with_stage(mut self, stage: u32) -> Compiler {
         self.stage = stage;
         self
diff --git a/src/build_helper/lib.rs b/src/build_helper/lib.rs
index f9371e878ef..c30307f3a1b 100644
--- a/src/build_helper/lib.rs
+++ b/src/build_helper/lib.rs
@@ -1,5 +1,5 @@
 // NO-RUSTC-WRAPPER
-#![deny(warnings, rust_2018_idioms)]
+#![deny(warnings, rust_2018_idioms, unused_lifetimes)]
 
 use std::fs::File;
 use std::path::{Path, PathBuf};
diff --git a/src/liballoc/string.rs b/src/liballoc/string.rs
index 366191e2c85..eca726cd410 100644
--- a/src/liballoc/string.rs
+++ b/src/liballoc/string.rs
@@ -1838,6 +1838,7 @@ impl PartialEq for String {
 macro_rules! impl_eq {
     ($lhs:ty, $rhs: ty) => {
         #[stable(feature = "rust1", since = "1.0.0")]
+        #[allow(unused_lifetimes)]
         impl<'a, 'b> PartialEq<$rhs> for $lhs {
             #[inline]
             fn eq(&self, other: &$rhs) -> bool { PartialEq::eq(&self[..], &other[..]) }
@@ -1846,6 +1847,7 @@ macro_rules! impl_eq {
         }
 
         #[stable(feature = "rust1", since = "1.0.0")]
+        #[allow(unused_lifetimes)]
         impl<'a, 'b> PartialEq<$lhs> for $rhs {
             #[inline]
             fn eq(&self, other: &$lhs) -> bool { PartialEq::eq(&self[..], &other[..]) }
diff --git a/src/libarena/lib.rs b/src/libarena/lib.rs
index 7baec3ed1cf..690d8344acf 100644
--- a/src/libarena/lib.rs
+++ b/src/libarena/lib.rs
@@ -11,8 +11,6 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/",
        test(no_crate_inject, attr(deny(warnings))))]
 
-#![deny(unused_lifetimes)]
-
 #![feature(core_intrinsics)]
 #![feature(dropck_eyepatch)]
 #![feature(raw_vec_internals)]
diff --git a/src/libcore/array.rs b/src/libcore/array.rs
index 6ecc0487fae..6023bc21e74 100644
--- a/src/libcore/array.rs
+++ b/src/libcore/array.rs
@@ -250,7 +250,7 @@ where
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, 'b, A, B, const N: usize> PartialEq<[A; N]> for [B]
+impl<A, B, const N: usize> PartialEq<[A; N]> for [B]
 where
     B: PartialEq<A>,
     [A; N]: LengthAtMost32,
@@ -266,7 +266,7 @@ where
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, 'b, A, B, const N: usize> PartialEq<&'b [B]> for [A; N]
+impl<'b, A, B, const N: usize> PartialEq<&'b [B]> for [A; N]
 where
     A: PartialEq<B>,
     [A; N]: LengthAtMost32,
@@ -282,7 +282,7 @@ where
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, 'b, A, B, const N: usize> PartialEq<[A; N]> for &'b [B]
+impl<'b, A, B, const N: usize> PartialEq<[A; N]> for &'b [B]
 where
     B: PartialEq<A>,
     [A; N]: LengthAtMost32,
@@ -298,7 +298,7 @@ where
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, 'b, A, B, const N: usize> PartialEq<&'b mut [B]> for [A; N]
+impl<'b, A, B, const N: usize> PartialEq<&'b mut [B]> for [A; N]
 where
     A: PartialEq<B>,
     [A; N]: LengthAtMost32,
@@ -314,7 +314,7 @@ where
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, 'b, A, B, const N: usize> PartialEq<[A; N]> for &'b mut [B]
+impl<'b, A, B, const N: usize> PartialEq<[A; N]> for &'b mut [B]
 where
     B: PartialEq<A>,
     [A; N]: LengthAtMost32,
diff --git a/src/libcore/pin.rs b/src/libcore/pin.rs
index 2feaab7a09c..88a56174629 100644
--- a/src/libcore/pin.rs
+++ b/src/libcore/pin.rs
@@ -775,7 +775,7 @@ where
 {}
 
 #[stable(feature = "pin", since = "1.33.0")]
-impl<'a, P, U> DispatchFromDyn<Pin<U>> for Pin<P>
+impl<P, U> DispatchFromDyn<Pin<U>> for Pin<P>
 where
     P: DispatchFromDyn<U>,
 {}
diff --git a/src/libcore/ptr/unique.rs b/src/libcore/ptr/unique.rs
index d2517e51fc5..f0d011fe6b2 100644
--- a/src/libcore/ptr/unique.rs
+++ b/src/libcore/ptr/unique.rs
@@ -172,7 +172,7 @@ impl<T: ?Sized> From<&T> for Unique<T> {
 }
 
 #[unstable(feature = "ptr_internals", issue = "0")]
-impl<'a, T: ?Sized> From<NonNull<T>> for Unique<T> {
+impl<T: ?Sized> From<NonNull<T>> for Unique<T> {
     #[inline]
     fn from(p: NonNull<T>) -> Self {
         unsafe { Unique::new_unchecked(p.as_ptr()) }
diff --git a/src/libfmt_macros/lib.rs b/src/libfmt_macros/lib.rs
index d673088fe45..83e24a48ea0 100644
--- a/src/libfmt_macros/lib.rs
+++ b/src/libfmt_macros/lib.rs
@@ -8,8 +8,6 @@
        html_playground_url = "https://play.rust-lang.org/",
        test(attr(deny(warnings))))]
 
-#![deny(unused_lifetimes)]
-
 #![feature(nll)]
 #![feature(rustc_private)]
 #![feature(unicode_internals)]
diff --git a/src/libproc_macro/bridge/scoped_cell.rs b/src/libproc_macro/bridge/scoped_cell.rs
index 89fb7070015..2cde1f65adf 100644
--- a/src/libproc_macro/bridge/scoped_cell.rs
+++ b/src/libproc_macro/bridge/scoped_cell.rs
@@ -5,6 +5,7 @@ use std::mem;
 use std::ops::{Deref, DerefMut};
 
 /// Type lambda application, with a lifetime.
+#[allow(unused_lifetimes)]
 pub trait ApplyL<'a> {
     type Out;
 }
diff --git a/src/librustc/lib.rs b/src/librustc/lib.rs
index 9957b173116..4b3fefcd4de 100644
--- a/src/librustc/lib.rs
+++ b/src/librustc/lib.rs
@@ -28,8 +28,6 @@
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
-#![deny(unused_lifetimes)]
-
 #![feature(arbitrary_self_types)]
 #![feature(box_patterns)]
 #![feature(box_syntax)]
diff --git a/src/librustc_ast_borrowck/lib.rs b/src/librustc_ast_borrowck/lib.rs
index 045671e37c0..dc818278a4b 100644
--- a/src/librustc_ast_borrowck/lib.rs
+++ b/src/librustc_ast_borrowck/lib.rs
@@ -1,7 +1,6 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
 #![allow(non_camel_case_types)]
-#![deny(unused_lifetimes)]
 
 #![feature(in_band_lifetimes)]
 #![feature(nll)]
diff --git a/src/librustc_codegen_llvm/lib.rs b/src/librustc_codegen_llvm/lib.rs
index 90609d6c85a..a630817fb33 100644
--- a/src/librustc_codegen_llvm/lib.rs
+++ b/src/librustc_codegen_llvm/lib.rs
@@ -21,7 +21,6 @@
 #![feature(static_nobundle)]
 #![feature(trusted_len)]
 #![feature(mem_take)]
-#![deny(unused_lifetimes)]
 
 use back::write::{create_target_machine, create_informational_target_machine};
 use syntax_pos::symbol::Symbol;
diff --git a/src/librustc_codegen_ssa/lib.rs b/src/librustc_codegen_ssa/lib.rs
index 4e2977a011c..73ef16e0091 100644
--- a/src/librustc_codegen_ssa/lib.rs
+++ b/src/librustc_codegen_ssa/lib.rs
@@ -11,7 +11,6 @@
 #![feature(nll)]
 #![feature(trusted_len)]
 #![feature(mem_take)]
-#![deny(unused_lifetimes)]
 
 #![recursion_limit="256"]
 
diff --git a/src/librustc_codegen_utils/lib.rs b/src/librustc_codegen_utils/lib.rs
index e3fafc2f2cd..4ea375b59b2 100644
--- a/src/librustc_codegen_utils/lib.rs
+++ b/src/librustc_codegen_utils/lib.rs
@@ -15,8 +15,6 @@
 
 #![recursion_limit="256"]
 
-#![deny(unused_lifetimes)]
-
 #[macro_use]
 extern crate rustc;
 
diff --git a/src/librustc_data_structures/graph/mod.rs b/src/librustc_data_structures/graph/mod.rs
index e59085a9e3a..749709521e8 100644
--- a/src/librustc_data_structures/graph/mod.rs
+++ b/src/librustc_data_structures/graph/mod.rs
@@ -39,6 +39,7 @@ where
     }
 }
 
+#[allow(unused_lifetimes)]
 pub trait GraphSuccessors<'graph> {
     type Item;
     type Iter: Iterator<Item = Self::Item>;
@@ -54,6 +55,7 @@ where
     ) -> <Self as GraphPredecessors<'_>>::Iter;
 }
 
+#[allow(unused_lifetimes)]
 pub trait GraphPredecessors<'graph> {
     type Item;
     type Iter: Iterator<Item = Self::Item>;
diff --git a/src/librustc_data_structures/owning_ref/mod.rs b/src/librustc_data_structures/owning_ref/mod.rs
index a7af615fa50..3b49ce71063 100644
--- a/src/librustc_data_structures/owning_ref/mod.rs
+++ b/src/librustc_data_structures/owning_ref/mod.rs
@@ -283,6 +283,7 @@ impl<T> Erased for T {}
 /// Helper trait for erasing the concrete type of what an owner dereferences to,
 /// for example `Box<T> -> Box<Erased>`. This would be unneeded with
 /// higher kinded types support in the language.
+#[allow(unused_lifetimes)]
 pub unsafe trait IntoErased<'a> {
     /// Owner with the dereference type substituted to `Erased`.
     type Erased;
@@ -293,6 +294,7 @@ pub unsafe trait IntoErased<'a> {
 /// Helper trait for erasing the concrete type of what an owner dereferences to,
 /// for example `Box<T> -> Box<Erased + Send>`. This would be unneeded with
 /// higher kinded types support in the language.
+#[allow(unused_lifetimes)]
 pub unsafe trait IntoErasedSend<'a> {
     /// Owner with the dereference type substituted to `Erased + Send`.
     type Erased: Send;
@@ -303,6 +305,7 @@ pub unsafe trait IntoErasedSend<'a> {
 /// Helper trait for erasing the concrete type of what an owner dereferences to,
 /// for example `Box<T> -> Box<Erased + Send + Sync>`. This would be unneeded with
 /// higher kinded types support in the language.
+#[allow(unused_lifetimes)]
 pub unsafe trait IntoErasedSendSync<'a> {
     /// Owner with the dereference type substituted to `Erased + Send + Sync`.
     type Erased: Send + Sync;
diff --git a/src/librustc_driver/lib.rs b/src/librustc_driver/lib.rs
index 66739761ef0..77b7ef96d3f 100644
--- a/src/librustc_driver/lib.rs
+++ b/src/librustc_driver/lib.rs
@@ -16,8 +16,6 @@
 
 #![recursion_limit="256"]
 
-#![deny(unused_lifetimes)]
-
 pub extern crate getopts;
 #[cfg(unix)]
 extern crate libc;
diff --git a/src/librustc_errors/lib.rs b/src/librustc_errors/lib.rs
index f252d0573dc..3f758c2521b 100644
--- a/src/librustc_errors/lib.rs
+++ b/src/librustc_errors/lib.rs
@@ -8,7 +8,6 @@
 #![cfg_attr(unix, feature(libc))]
 #![feature(nll)]
 #![feature(optin_builtin_traits)]
-#![deny(unused_lifetimes)]
 
 pub use emitter::ColorConfig;
 
diff --git a/src/librustc_incremental/lib.rs b/src/librustc_incremental/lib.rs
index 0b5eb41605b..b2573111385 100644
--- a/src/librustc_incremental/lib.rs
+++ b/src/librustc_incremental/lib.rs
@@ -8,8 +8,6 @@
 
 #![recursion_limit="256"]
 
-#![deny(unused_lifetimes)]
-
 #[macro_use] extern crate rustc;
 #[macro_use] extern crate log;
 
diff --git a/src/librustc_interface/lib.rs b/src/librustc_interface/lib.rs
index f4e4612007c..2e593d44155 100644
--- a/src/librustc_interface/lib.rs
+++ b/src/librustc_interface/lib.rs
@@ -6,8 +6,6 @@
 #![feature(generators)]
 #![cfg_attr(unix, feature(libc))]
 
-#![deny(unused_lifetimes)]
-
 #![recursion_limit="256"]
 
 #[cfg(unix)]
diff --git a/src/librustc_lint/lib.rs b/src/librustc_lint/lib.rs
index 1d3b2b62996..d3975360525 100644
--- a/src/librustc_lint/lib.rs
+++ b/src/librustc_lint/lib.rs
@@ -19,8 +19,6 @@
 
 #![recursion_limit="256"]
 
-#![deny(unused_lifetimes)]
-
 #[macro_use]
 extern crate rustc;
 
diff --git a/src/librustc_metadata/lib.rs b/src/librustc_metadata/lib.rs
index ce7fb7cdc66..c96d02d9b37 100644
--- a/src/librustc_metadata/lib.rs
+++ b/src/librustc_metadata/lib.rs
@@ -15,8 +15,6 @@
 
 #![recursion_limit="256"]
 
-#![deny(unused_lifetimes)]
-
 extern crate libc;
 extern crate proc_macro;
 
diff --git a/src/librustc_mir/lib.rs b/src/librustc_mir/lib.rs
index 28e5c5dc99a..20d5e54d2ce 100644
--- a/src/librustc_mir/lib.rs
+++ b/src/librustc_mir/lib.rs
@@ -26,8 +26,6 @@ Rust MIR: a lowered representation of Rust. Also: an experiment!
 
 #![recursion_limit="256"]
 
-#![deny(unused_lifetimes)]
-
 #[macro_use] extern crate log;
 #[macro_use] extern crate rustc;
 #[macro_use] extern crate rustc_data_structures;
diff --git a/src/librustc_passes/lib.rs b/src/librustc_passes/lib.rs
index 6c11d82958b..5614b570b92 100644
--- a/src/librustc_passes/lib.rs
+++ b/src/librustc_passes/lib.rs
@@ -13,8 +13,6 @@
 
 #![recursion_limit="256"]
 
-#![deny(unused_lifetimes)]
-
 #[macro_use]
 extern crate rustc;
 
diff --git a/src/librustc_privacy/lib.rs b/src/librustc_privacy/lib.rs
index 75c98753d31..e291f40ffd2 100644
--- a/src/librustc_privacy/lib.rs
+++ b/src/librustc_privacy/lib.rs
@@ -1,7 +1,5 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
-#![deny(unused_lifetimes)]
-
 #![feature(in_band_lifetimes)]
 #![feature(nll)]
 #![feature(rustc_diagnostic_macros)]
diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index c7982b4a396..bc5898fe78d 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -10,8 +10,6 @@
 
 #![recursion_limit="256"]
 
-#![deny(unused_lifetimes)]
-
 pub use rustc::hir::def::{Namespace, PerNS};
 
 use Determinacy::*;
diff --git a/src/librustc_save_analysis/lib.rs b/src/librustc_save_analysis/lib.rs
index 1e18b34e5c8..9edb4c0fa67 100644
--- a/src/librustc_save_analysis/lib.rs
+++ b/src/librustc_save_analysis/lib.rs
@@ -1,10 +1,8 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 #![feature(nll)]
-#![deny(unused_lifetimes)]
 
 #![recursion_limit="256"]
 
-
 mod dumper;
 mod dump_visitor;
 #[macro_use]
diff --git a/src/librustc_target/lib.rs b/src/librustc_target/lib.rs
index 0fc5fbdc6a2..a349dc26e83 100644
--- a/src/librustc_target/lib.rs
+++ b/src/librustc_target/lib.rs
@@ -13,8 +13,6 @@
 #![feature(nll)]
 #![feature(slice_patterns)]
 
-#![deny(unused_lifetimes)]
-
 #[macro_use] extern crate log;
 
 pub mod abi;
diff --git a/src/librustc_traits/lib.rs b/src/librustc_traits/lib.rs
index ec5a8bc544b..ebe6b7c6138 100644
--- a/src/librustc_traits/lib.rs
+++ b/src/librustc_traits/lib.rs
@@ -1,8 +1,6 @@
 //! New recursive solver modeled on Chalk's recursive solver. Most of
 //! the guts are broken up into modules; see the comments in those modules.
 
-#![deny(unused_lifetimes)]
-
 #![feature(crate_visibility_modifier)]
 #![feature(in_band_lifetimes)]
 #![feature(nll)]
diff --git a/src/librustc_typeck/lib.rs b/src/librustc_typeck/lib.rs
index 284b1d533d5..a34b137aca9 100644
--- a/src/librustc_typeck/lib.rs
+++ b/src/librustc_typeck/lib.rs
@@ -73,8 +73,6 @@ This API is completely unstable and subject to change.
 
 #![recursion_limit="256"]
 
-#![deny(unused_lifetimes)]
-
 #[macro_use] extern crate log;
 #[macro_use] extern crate syntax;
 
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 74a7b2b9152..a8d7ff4a2eb 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -1,5 +1,3 @@
-#![deny(unused_lifetimes)]
-
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/",
        html_playground_url = "https://play.rust-lang.org/")]
 
diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index 1390341cf7c..8fd76eabe39 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -210,6 +210,7 @@
 #![warn(missing_debug_implementations)]
 #![deny(intra_doc_link_resolution_failure)] // rustdoc is run without -D warnings
 #![allow(explicit_outlives_requirements)]
+#![allow(unused_lifetimes)]
 
 // Tell the compiler to link to either panic_abort or panic_unwind
 #![needs_panic_runtime]
diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index 5ef80518b40..1fd20fa0b31 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -7,8 +7,6 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/",
        test(attr(deny(warnings))))]
 
-#![deny(unused_lifetimes)]
-
 #![feature(bind_by_move_pattern_guards)]
 #![feature(box_syntax)]
 #![feature(const_fn)]
diff --git a/src/libsyntax_ext/lib.rs b/src/libsyntax_ext/lib.rs
index 21031109f2a..da11f2ff23f 100644
--- a/src/libsyntax_ext/lib.rs
+++ b/src/libsyntax_ext/lib.rs
@@ -3,8 +3,6 @@
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
-#![deny(unused_lifetimes)]
-
 #![feature(crate_visibility_modifier)]
 #![feature(decl_macro)]
 #![feature(mem_take)]
diff --git a/src/libsyntax_pos/lib.rs b/src/libsyntax_pos/lib.rs
index bc7be9f34ee..acc13aec402 100644
--- a/src/libsyntax_pos/lib.rs
+++ b/src/libsyntax_pos/lib.rs
@@ -6,8 +6,6 @@
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
-#![deny(unused_lifetimes)]
-
 #![feature(const_fn)]
 #![feature(crate_visibility_modifier)]
 #![feature(nll)]