diff --git a/compiler/rustc_data_structures/src/lib.rs b/compiler/rustc_data_structures/src/lib.rs
index 1a3fe652521..98d4870e645 100644
--- a/compiler/rustc_data_structures/src/lib.rs
+++ b/compiler/rustc_data_structures/src/lib.rs
@@ -27,7 +27,6 @@
 #![feature(thread_id_value)]
 #![feature(vec_into_raw_parts)]
 #![allow(rustc::default_hash_types)]
-#![deny(unaligned_references)]
 #![allow(rustc::potential_query_instability)]
 
 #[macro_use]
diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs
index 89ce307d12c..0953e5eeb14 100644
--- a/compiler/rustc_lint_defs/src/builtin.rs
+++ b/compiler/rustc_lint_defs/src/builtin.rs
@@ -1110,8 +1110,6 @@ declare_lint! {
     /// ### Example
     ///
     /// ```rust,compile_fail
-    /// #![deny(unaligned_references)]
-    ///
     /// #[repr(packed)]
     /// pub struct Foo {
     ///     field1: u64,
@@ -1139,7 +1137,7 @@ declare_lint! {
     /// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
     /// [issue #82523]: https://github.com/rust-lang/rust/issues/82523
     pub UNALIGNED_REFERENCES,
-    Warn,
+    Deny,
     "detects unaligned references to fields of packed structs",
     @future_incompatible = FutureIncompatibleInfo {
         reference: "issue #82523 <https://github.com/rust-lang/rust/issues/82523>",
diff --git a/src/test/ui/binding/issue-53114-safety-checks.rs b/src/test/ui/binding/issue-53114-safety-checks.rs
index ca4f0efd239..5042ad024af 100644
--- a/src/test/ui/binding/issue-53114-safety-checks.rs
+++ b/src/test/ui/binding/issue-53114-safety-checks.rs
@@ -20,13 +20,13 @@ fn let_wild_gets_unsafe_field() {
     let u1 = U { a: I(0) };
     let u2 = U { a: I(1) };
     let p = P { a: &2, b: &3 };
-    let _ = &p.b;  //~ WARN    reference to packed field
+    let _ = &p.b;  //~ ERROR    reference to packed field
     //~^  WARN will become a hard error
     let _ = u1.a;  // #53114: should eventually signal error as well
     let _ = &u2.a; //~ ERROR  [E0133]
 
     // variation on above with `_` in substructure
-    let (_,) = (&p.b,);  //~ WARN     reference to packed field
+    let (_,) = (&p.b,);  //~ ERROR     reference to packed field
     //~^  WARN will become a hard error
     let (_,) = (u1.a,);  //~ ERROR   [E0133]
     let (_,) = (&u2.a,); //~ ERROR   [E0133]
@@ -36,13 +36,13 @@ fn match_unsafe_field_to_wild() {
     let u1 = U { a: I(0) };
     let u2 = U { a: I(1) };
     let p = P { a: &2, b: &3 };
-    match &p.b  { _ => { } } //~ WARN     reference to packed field
+    match &p.b  { _ => { } } //~ ERROR     reference to packed field
     //~^  WARN will become a hard error
     match u1.a  { _ => { } } //~ ERROR   [E0133]
     match &u2.a { _ => { } } //~ ERROR   [E0133]
 
     // variation on above with `_` in substructure
-    match (&p.b,)  { (_,) => { } } //~ WARN     reference to packed field
+    match (&p.b,)  { (_,) => { } } //~ ERROR     reference to packed field
     //~^  WARN will become a hard error
     match (u1.a,)  { (_,) => { } } //~ ERROR   [E0133]
     match (&u2.a,) { (_,) => { } } //~ ERROR   [E0133]
diff --git a/src/test/ui/binding/issue-53114-safety-checks.stderr b/src/test/ui/binding/issue-53114-safety-checks.stderr
index 84cdb1453f8..66727086bf4 100644
--- a/src/test/ui/binding/issue-53114-safety-checks.stderr
+++ b/src/test/ui/binding/issue-53114-safety-checks.stderr
@@ -1,16 +1,16 @@
-warning: reference to packed field is unaligned
+error: reference to packed field is unaligned
   --> $DIR/issue-53114-safety-checks.rs:23:13
    |
 LL |     let _ = &p.b;
    |             ^^^^
    |
-   = note: `#[warn(unaligned_references)]` on by default
+   = note: `#[deny(unaligned_references)]` on by default
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #82523 <https://github.com/rust-lang/rust/issues/82523>
    = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
    = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers)
 
-warning: reference to packed field is unaligned
+error: reference to packed field is unaligned
   --> $DIR/issue-53114-safety-checks.rs:29:17
    |
 LL |     let (_,) = (&p.b,);
@@ -21,7 +21,7 @@ LL |     let (_,) = (&p.b,);
    = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
    = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers)
 
-warning: reference to packed field is unaligned
+error: reference to packed field is unaligned
   --> $DIR/issue-53114-safety-checks.rs:39:11
    |
 LL |     match &p.b  { _ => { } }
@@ -32,7 +32,7 @@ LL |     match &p.b  { _ => { } }
    = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
    = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers)
 
-warning: reference to packed field is unaligned
+error: reference to packed field is unaligned
   --> $DIR/issue-53114-safety-checks.rs:45:12
    |
 LL |     match (&p.b,)  { (_,) => { } }
@@ -99,6 +99,6 @@ LL |     match (&u2.a,) { (_,) => { } }
    |
    = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior
 
-error: aborting due to 7 previous errors; 4 warnings emitted
+error: aborting due to 11 previous errors
 
 For more information about this error, try `rustc --explain E0133`.
diff --git a/src/test/ui/closures/2229_closure_analysis/diagnostics/repr_packed.rs b/src/test/ui/closures/2229_closure_analysis/diagnostics/repr_packed.rs
index 4799f488d7d..1488f329648 100644
--- a/src/test/ui/closures/2229_closure_analysis/diagnostics/repr_packed.rs
+++ b/src/test/ui/closures/2229_closure_analysis/diagnostics/repr_packed.rs
@@ -1,7 +1,5 @@
 // edition:2021
 
-// check-pass
-
 // Given how the closure desugaring is implemented (at least at the time of writing this test),
 // we don't need to truncate the captured path to a reference into a packed-struct if the field
 // being referenced will be moved into the closure, since it's safe to move out a field from a
@@ -11,9 +9,8 @@
 // inlined we will truncate the capture to access just the struct regardless of if the field
 // might get moved into the closure.
 //
-// It is possible for someone to try writing the code that relies on the desugaring to access a ref
-// into a packed-struct without explicity using unsafe. Here we test that the compiler warns the
-// user that such an access is still unsafe.
+// It is possible for someone to try writing the code that relies on the desugaring to create a ref
+// into a packed-struct. Here we test that the compiler still detects that case.
 fn test_missing_unsafe_warning_on_repr_packed() {
     #[repr(packed)]
     struct Foo { x: String }
@@ -22,7 +19,7 @@ fn test_missing_unsafe_warning_on_repr_packed() {
 
     let c = || {
         println!("{}", foo.x);
-        //~^ WARNING: reference to packed field is unaligned
+        //~^ ERROR: reference to packed field is unaligned
         //~| WARNING: this was previously accepted by the compiler but is being phased out
         let _z = foo.x;
     };
diff --git a/src/test/ui/closures/2229_closure_analysis/diagnostics/repr_packed.stderr b/src/test/ui/closures/2229_closure_analysis/diagnostics/repr_packed.stderr
index fc0179d2cb4..276a1f00f8d 100644
--- a/src/test/ui/closures/2229_closure_analysis/diagnostics/repr_packed.stderr
+++ b/src/test/ui/closures/2229_closure_analysis/diagnostics/repr_packed.stderr
@@ -1,15 +1,15 @@
-warning: reference to packed field is unaligned
-  --> $DIR/repr_packed.rs:24:24
+error: reference to packed field is unaligned
+  --> $DIR/repr_packed.rs:21:24
    |
 LL |         println!("{}", foo.x);
    |                        ^^^^^
    |
-   = note: `#[warn(unaligned_references)]` on by default
+   = note: `#[deny(unaligned_references)]` on by default
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #82523 <https://github.com/rust-lang/rust/issues/82523>
    = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
    = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers)
-   = note: this warning originates in the macro `$crate::format_args_nl` (in Nightly builds, run with -Z macro-backtrace for more info)
+   = note: this error originates in the macro `$crate::format_args_nl` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-warning: 1 warning emitted
+error: aborting due to previous error
 
diff --git a/src/test/ui/packed/issue-27060.rs b/src/test/ui/packed/issue-27060.rs
index 5317a616719..886a00239f9 100644
--- a/src/test/ui/packed/issue-27060.rs
+++ b/src/test/ui/packed/issue-27060.rs
@@ -5,7 +5,6 @@ pub struct Good {
     aligned: [u8; 32],
 }
 
-#[deny(unaligned_references)]
 fn main() {
     let good = Good {
         data: &0,
diff --git a/src/test/ui/packed/issue-27060.stderr b/src/test/ui/packed/issue-27060.stderr
index bba056d59f8..58dc816a142 100644
--- a/src/test/ui/packed/issue-27060.stderr
+++ b/src/test/ui/packed/issue-27060.stderr
@@ -1,21 +1,17 @@
 error: reference to packed field is unaligned
-  --> $DIR/issue-27060.rs:16:13
+  --> $DIR/issue-27060.rs:15:13
    |
 LL |     let _ = &good.data;
    |             ^^^^^^^^^^
    |
-note: the lint level is defined here
-  --> $DIR/issue-27060.rs:8:8
-   |
-LL | #[deny(unaligned_references)]
-   |        ^^^^^^^^^^^^^^^^^^^^
+   = note: `#[deny(unaligned_references)]` on by default
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #82523 <https://github.com/rust-lang/rust/issues/82523>
    = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
    = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers)
 
 error: reference to packed field is unaligned
-  --> $DIR/issue-27060.rs:18:13
+  --> $DIR/issue-27060.rs:17:13
    |
 LL |     let _ = &good.data2[0];
    |             ^^^^^^^^^^^^^^
@@ -26,7 +22,7 @@ LL |     let _ = &good.data2[0];
    = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers)
 
 error: reference to packed field is unaligned
-  --> $DIR/issue-27060.rs:21:13
+  --> $DIR/issue-27060.rs:20:13
    |
 LL |     let _ = &good.data;
    |             ^^^^^^^^^^
@@ -37,7 +33,7 @@ LL |     let _ = &good.data;
    = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers)
 
 error: reference to packed field is unaligned
-  --> $DIR/issue-27060.rs:23:13
+  --> $DIR/issue-27060.rs:22:13
    |
 LL |     let _ = &good.data2[0];
    |             ^^^^^^^^^^^^^^
diff --git a/src/test/ui/packed/packed-struct-address-of-element.rs b/src/test/ui/packed/packed-struct-address-of-element.rs
index fb3875e6804..d86698cbf38 100644
--- a/src/test/ui/packed/packed-struct-address-of-element.rs
+++ b/src/test/ui/packed/packed-struct-address-of-element.rs
@@ -1,6 +1,5 @@
 // run-pass
 #![allow(dead_code)]
-#![deny(unaligned_references)]
 #![feature(raw_ref_op)]
 // ignore-emscripten weird assertion?
 
diff --git a/src/test/ui/packed/packed-struct-borrow-element-64bit.rs b/src/test/ui/packed/packed-struct-borrow-element-64bit.rs
index ad932fdcd01..00bddfe40b2 100644
--- a/src/test/ui/packed/packed-struct-borrow-element-64bit.rs
+++ b/src/test/ui/packed/packed-struct-borrow-element-64bit.rs
@@ -9,6 +9,7 @@ struct Foo4C {
     baz: usize
 }
 
+#[warn(unaligned_references)]
 pub fn main() {
     let foo = Foo4C { bar: 1, baz: 2 };
     let brw = &foo.baz; //~WARN reference to packed field is unaligned
diff --git a/src/test/ui/packed/packed-struct-borrow-element-64bit.stderr b/src/test/ui/packed/packed-struct-borrow-element-64bit.stderr
index 04585b49986..8ea26a971f4 100644
--- a/src/test/ui/packed/packed-struct-borrow-element-64bit.stderr
+++ b/src/test/ui/packed/packed-struct-borrow-element-64bit.stderr
@@ -1,10 +1,14 @@
 warning: reference to packed field is unaligned
-  --> $DIR/packed-struct-borrow-element-64bit.rs:14:15
+  --> $DIR/packed-struct-borrow-element-64bit.rs:15:15
    |
 LL |     let brw = &foo.baz;
    |               ^^^^^^^^
    |
-   = note: `#[warn(unaligned_references)]` on by default
+note: the lint level is defined here
+  --> $DIR/packed-struct-borrow-element-64bit.rs:12:8
+   |
+LL | #[warn(unaligned_references)]
+   |        ^^^^^^^^^^^^^^^^^^^^
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #82523 <https://github.com/rust-lang/rust/issues/82523>
    = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
diff --git a/src/test/ui/packed/packed-struct-borrow-element.rs b/src/test/ui/packed/packed-struct-borrow-element.rs
index fb6c9c11d56..a6ee90cef44 100644
--- a/src/test/ui/packed/packed-struct-borrow-element.rs
+++ b/src/test/ui/packed/packed-struct-borrow-element.rs
@@ -20,6 +20,7 @@ struct Foo4C {
     baz: usize
 }
 
+#[warn(unaligned_references)]
 pub fn main() {
     let foo = Foo1 { bar: 1, baz: 2 };
     let brw = &foo.baz; //~WARN reference to packed field is unaligned
diff --git a/src/test/ui/packed/packed-struct-borrow-element.stderr b/src/test/ui/packed/packed-struct-borrow-element.stderr
index a50b1302001..6860bb5e85a 100644
--- a/src/test/ui/packed/packed-struct-borrow-element.stderr
+++ b/src/test/ui/packed/packed-struct-borrow-element.stderr
@@ -1,17 +1,21 @@
 warning: reference to packed field is unaligned
-  --> $DIR/packed-struct-borrow-element.rs:25:15
+  --> $DIR/packed-struct-borrow-element.rs:26:15
    |
 LL |     let brw = &foo.baz;
    |               ^^^^^^^^
    |
-   = note: `#[warn(unaligned_references)]` on by default
+note: the lint level is defined here
+  --> $DIR/packed-struct-borrow-element.rs:23:8
+   |
+LL | #[warn(unaligned_references)]
+   |        ^^^^^^^^^^^^^^^^^^^^
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #82523 <https://github.com/rust-lang/rust/issues/82523>
    = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
    = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers)
 
 warning: reference to packed field is unaligned
-  --> $DIR/packed-struct-borrow-element.rs:30:15
+  --> $DIR/packed-struct-borrow-element.rs:31:15
    |
 LL |     let brw = &foo.baz;
    |               ^^^^^^^^