diff --git a/compiler/rustc_ast/src/lib.rs b/compiler/rustc_ast/src/lib.rs
index cbdc89f9deed..10a8e181c840 100644
--- a/compiler/rustc_ast/src/lib.rs
+++ b/compiler/rustc_ast/src/lib.rs
@@ -6,6 +6,7 @@
 
 // tidy-alphabetical-start
 #![cfg_attr(bootstrap, feature(array_windows))]
+#![deny(clippy::manual_let_else)]
 #![doc(test(attr(deny(warnings), allow(internal_features))))]
 #![feature(associated_type_defaults)]
 #![feature(box_patterns)]
diff --git a/compiler/rustc_borrowck/src/lib.rs b/compiler/rustc_borrowck/src/lib.rs
index 8d61ffde116c..d82357fca2d4 100644
--- a/compiler/rustc_borrowck/src/lib.rs
+++ b/compiler/rustc_borrowck/src/lib.rs
@@ -2,6 +2,7 @@
 
 // tidy-alphabetical-start
 #![allow(internal_features)]
+#![deny(clippy::manual_let_else)]
 #![feature(assert_matches)]
 #![feature(box_patterns)]
 #![feature(file_buffered)]
diff --git a/compiler/rustc_const_eval/src/lib.rs b/compiler/rustc_const_eval/src/lib.rs
index 2fce4b8c0566..6c74ed2a5121 100644
--- a/compiler/rustc_const_eval/src/lib.rs
+++ b/compiler/rustc_const_eval/src/lib.rs
@@ -1,5 +1,6 @@
 // tidy-alphabetical-start
 #![allow(rustc::diagnostic_outside_of_impl)]
+#![deny(clippy::manual_let_else)]
 #![feature(array_try_map)]
 #![feature(assert_matches)]
 #![feature(box_patterns)]
diff --git a/compiler/rustc_hir/src/lib.rs b/compiler/rustc_hir/src/lib.rs
index 7a5776f0d5a9..c27954b6d14e 100644
--- a/compiler/rustc_hir/src/lib.rs
+++ b/compiler/rustc_hir/src/lib.rs
@@ -4,6 +4,7 @@
 
 // tidy-alphabetical-start
 #![cfg_attr(bootstrap, feature(debug_closure_helpers))]
+#![deny(clippy::manual_let_else)]
 #![feature(associated_type_defaults)]
 #![feature(closure_track_caller)]
 #![feature(const_default)]
diff --git a/compiler/rustc_hir_analysis/src/lib.rs b/compiler/rustc_hir_analysis/src/lib.rs
index 538fb8c7df1e..79c5fbab1ffa 100644
--- a/compiler/rustc_hir_analysis/src/lib.rs
+++ b/compiler/rustc_hir_analysis/src/lib.rs
@@ -59,6 +59,7 @@ This API is completely unstable and subject to change.
 #![allow(rustc::diagnostic_outside_of_impl)]
 #![allow(rustc::untranslatable_diagnostic)]
 #![cfg_attr(bootstrap, feature(debug_closure_helpers))]
+#![deny(clippy::manual_let_else)]
 #![feature(assert_matches)]
 #![feature(gen_blocks)]
 #![feature(if_let_guard)]
diff --git a/compiler/rustc_hir_typeck/src/lib.rs b/compiler/rustc_hir_typeck/src/lib.rs
index d3ef1d63e8ba..9ca5ddd494ae 100644
--- a/compiler/rustc_hir_typeck/src/lib.rs
+++ b/compiler/rustc_hir_typeck/src/lib.rs
@@ -1,4 +1,5 @@
 // tidy-alphabetical-start
+#![deny(clippy::manual_let_else)]
 #![feature(assert_matches)]
 #![feature(box_patterns)]
 #![feature(if_let_guard)]
diff --git a/compiler/rustc_lint/src/lib.rs b/compiler/rustc_lint/src/lib.rs
index 4e7a3e405176..49929a0a9bc7 100644
--- a/compiler/rustc_lint/src/lib.rs
+++ b/compiler/rustc_lint/src/lib.rs
@@ -22,6 +22,7 @@
 // tidy-alphabetical-start
 #![allow(internal_features)]
 #![cfg_attr(bootstrap, feature(array_windows))]
+#![deny(clippy::manual_let_else)]
 #![feature(assert_matches)]
 #![feature(box_patterns)]
 #![feature(if_let_guard)]
diff --git a/compiler/rustc_middle/src/lib.rs b/compiler/rustc_middle/src/lib.rs
index 5f62d44df6b6..ee3e89e57bd4 100644
--- a/compiler/rustc_middle/src/lib.rs
+++ b/compiler/rustc_middle/src/lib.rs
@@ -30,6 +30,7 @@
 #![allow(rustc::direct_use_of_rustc_type_ir)]
 #![allow(rustc::untranslatable_diagnostic)]
 #![cfg_attr(bootstrap, feature(array_windows))]
+#![deny(clippy::manual_let_else)]
 #![feature(allocator_api)]
 #![feature(assert_matches)]
 #![feature(associated_type_defaults)]
diff --git a/compiler/rustc_next_trait_solver/src/lib.rs b/compiler/rustc_next_trait_solver/src/lib.rs
index 5fa29b7d9f81..117751810e29 100644
--- a/compiler/rustc_next_trait_solver/src/lib.rs
+++ b/compiler/rustc_next_trait_solver/src/lib.rs
@@ -8,6 +8,7 @@
 #![allow(rustc::direct_use_of_rustc_type_ir)]
 #![allow(rustc::usage_of_type_ir_inherent)]
 #![allow(rustc::usage_of_type_ir_traits)]
+#![deny(clippy::manual_let_else)]
 // tidy-alphabetical-end
 
 pub mod canonical;
diff --git a/compiler/rustc_resolve/src/lib.rs b/compiler/rustc_resolve/src/lib.rs
index 0b4ec6956bd1..38cf83dc23f7 100644
--- a/compiler/rustc_resolve/src/lib.rs
+++ b/compiler/rustc_resolve/src/lib.rs
@@ -10,6 +10,7 @@
 #![allow(internal_features)]
 #![allow(rustc::diagnostic_outside_of_impl)]
 #![allow(rustc::untranslatable_diagnostic)]
+#![deny(clippy::manual_let_else)]
 #![feature(arbitrary_self_types)]
 #![feature(assert_matches)]
 #![feature(box_patterns)]