3 files changed, 14 insertions, 7 deletions

diff --git a/tests/ui/packed/issue-27060.stderr b/tests/ui/packed/issue-27060.stderr
index b4753284f..4dc31a283 100644
--- a/tests/ui/packed/issue-27060.stderr
+++ b/tests/ui/packed/issue-27060.stderr
@@ -4,7 +4,8 @@ error[E0793]: reference to packed field is unaligned
 LL |     let _ = &good.data;
    |             ^^^^^^^^^^
    |
-   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
+   = note: packed structs are only aligned by one byte, and many modern architectures penalize unaligned field accesses
+   = note: 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[E0793]: reference to packed field is unaligned
@@ -13,7 +14,8 @@ error[E0793]: reference to packed field is unaligned
 LL |     let _ = &good.data2[0];
    |             ^^^^^^^^^^^^^^
    |
-   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
+   = note: packed structs are only aligned by one byte, and many modern architectures penalize unaligned field accesses
+   = note: 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[E0793]: reference to packed field is unaligned
@@ -22,7 +24,8 @@ error[E0793]: reference to packed field is unaligned
 LL |     let _ = &good.data;
    |             ^^^^^^^^^^
    |
-   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
+   = note: packed structs are only aligned by one byte, and many modern architectures penalize unaligned field accesses
+   = note: 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[E0793]: reference to packed field is unaligned
@@ -31,7 +34,8 @@ error[E0793]: reference to packed field is unaligned
 LL |     let _ = &good.data2[0];
    |             ^^^^^^^^^^^^^^
    |
-   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
+   = note: packed structs are only aligned by one byte, and many modern architectures penalize unaligned field accesses
+   = note: 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: aborting due to 4 previous errors
diff --git a/tests/ui/packed/packed-struct-borrow-element-64bit.stderr b/tests/ui/packed/packed-struct-borrow-element-64bit.stderr
index 32943b0f0..57630a4b4 100644
--- a/tests/ui/packed/packed-struct-borrow-element-64bit.stderr
+++ b/tests/ui/packed/packed-struct-borrow-element-64bit.stderr
@@ -4,7 +4,8 @@ error[E0793]: reference to packed field is unaligned
 LL |     let brw = &foo.baz;
    |               ^^^^^^^^
    |
-   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
+   = note: packed structs are only aligned by one byte, and many modern architectures penalize unaligned field accesses
+   = note: 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: aborting due to previous error
diff --git a/tests/ui/packed/packed-struct-borrow-element.stderr b/tests/ui/packed/packed-struct-borrow-element.stderr
index 29d867fc5..c1f749d6f 100644
--- a/tests/ui/packed/packed-struct-borrow-element.stderr
+++ b/tests/ui/packed/packed-struct-borrow-element.stderr
@@ -4,7 +4,8 @@ error[E0793]: reference to packed field is unaligned
 LL |     let brw = &foo.baz;
    |               ^^^^^^^^
    |
-   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
+   = note: packed structs are only aligned by one byte, and many modern architectures penalize unaligned field accesses
+   = note: 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[E0793]: reference to packed field is unaligned
@@ -13,7 +14,8 @@ error[E0793]: reference to packed field is unaligned
 LL |     let brw = &foo.baz;
    |               ^^^^^^^^
    |
-   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
+   = note: packed structs are only aligned by one byte, and many modern architectures penalize unaligned field accesses
+   = note: 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: aborting due to 2 previous errors