diff --git a/library/alloc/src/lib.rs b/library/alloc/src/lib.rs
index b84273848ee..45e93feb6c5 100644
--- a/library/alloc/src/lib.rs
+++ b/library/alloc/src/lib.rs
@@ -92,6 +92,7 @@
 #![warn(multiple_supertrait_upcastable)]
 #![allow(internal_features)]
 #![allow(rustdoc::redundant_explicit_links)]
+#![deny(ffi_unwind_calls)]
 //
 // Library features:
 // tidy-alphabetical-start
diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index 456d88122af..49cead680e3 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -106,6 +106,7 @@
 #![allow(incomplete_features)]
 #![warn(multiple_supertrait_upcastable)]
 #![allow(internal_features)]
+#![deny(ffi_unwind_calls)]
 // Do not check link redundancy on bootstraping phase
 #![allow(rustdoc::redundant_explicit_links)]
 //
diff --git a/library/proc_macro/src/lib.rs b/library/proc_macro/src/lib.rs
index d05458a6944..610966625b5 100644
--- a/library/proc_macro/src/lib.rs
+++ b/library/proc_macro/src/lib.rs
@@ -36,6 +36,7 @@
 #![feature(strict_provenance)]
 #![recursion_limit = "256"]
 #![allow(internal_features)]
+#![deny(ffi_unwind_calls)]
 
 #[unstable(feature = "proc_macro_internals", issue = "27812")]
 #[doc(hidden)]