4 files changed, 50 insertions, 2 deletions
diff --git a/tests/ui/layout/base-layout-is-sized-ice-123078.stderr b/tests/ui/layout/base-layout-is-sized-ice-123078.stderr
index 7e0a41a4367..455bd2cbf8b 100644
--- a/tests/ui/layout/base-layout-is-sized-ice-123078.stderr
+++ b/tests/ui/layout/base-layout-is-sized-ice-123078.stderr
@@ -23,7 +23,7 @@ LL | const C: S = unsafe { std::mem::transmute(()) };
    |                       ^^^^^^^^^^^^^^^^^^^
    |
    = note: source type: `()` (0 bits)
-   = note: target type: `S` (this type does not have a fixed size)
+   = note: target type: `S` (size can vary because of [u8])
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/transmute/transmute-different-sizes.rs b/tests/ui/transmute/transmute-different-sizes.rs
index 4fe79b9fa4e..ac98eb231dd 100644
--- a/tests/ui/transmute/transmute-different-sizes.rs
+++ b/tests/ui/transmute/transmute-different-sizes.rs
@@ -28,4 +28,24 @@ unsafe fn specializable<T>(x: u16) -> <T as Specializable>::Output {
     //~^ ERROR cannot transmute between types of different sizes, or dependently-sized types
 }
 
+#[repr(align(32))]
+struct OverAlignZST;
+pub struct PtrAndOverAlignZST<T: ?Sized> {
+    _inner: *mut T,
+    _other: OverAlignZST,
+}
+pub unsafe fn shouldnt_work<T: ?Sized>(from: *mut T) -> PtrAndOverAlignZST<T> {
+    transmute(from)
+    //~^ ERROR cannot transmute between types of different sizes, or dependently-sized types
+}
+
+pub struct PtrAndEmptyArray<T: ?Sized> {
+    _inner: *mut T,
+    _other: [*mut T; 0],
+}
+pub unsafe fn shouldnt_work2<T: ?Sized>(from: *mut T) -> PtrAndEmptyArray<T> {
+    std::mem::transmute(from)
+    //~^ ERROR cannot transmute between types of different sizes, or dependently-sized types
+}
+
 fn main() {}
diff --git a/tests/ui/transmute/transmute-different-sizes.stderr b/tests/ui/transmute/transmute-different-sizes.stderr
index 07a38df6973..ea3a017c16e 100644
--- a/tests/ui/transmute/transmute-different-sizes.stderr
+++ b/tests/ui/transmute/transmute-different-sizes.stderr
@@ -25,6 +25,24 @@ LL |     transmute(x)
    = note: source type: `u16` (N bits)
    = note: target type: `<T as Specializable>::Output` (this type does not have a fixed size)
 
-error: aborting due to 3 previous errors
+error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
+  --> $DIR/transmute-different-sizes.rs:38:5
+   |
+LL |     transmute(from)
+   |     ^^^^^^^^^
+   |
+   = note: source type: `*mut T` (pointer to `T`)
+   = note: target type: `PtrAndOverAlignZST<T>` (size can vary because of <T as Pointee>::Metadata)
+
+error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
+  --> $DIR/transmute-different-sizes.rs:47:5
+   |
+LL |     std::mem::transmute(from)
+   |     ^^^^^^^^^^^^^^^^^^^
+   |
+   = note: source type: `*mut T` (pointer to `T`)
+   = note: target type: `PtrAndEmptyArray<T>` (size can vary because of <T as Pointee>::Metadata)
+
+error: aborting due to 5 previous errors
 
 For more information about this error, try `rustc --explain E0512`.
diff --git a/tests/ui/transmute/transmute-zst-generics.rs b/tests/ui/transmute/transmute-zst-generics.rs
index 9aeb21923ea..b80ec794f83 100644
--- a/tests/ui/transmute/transmute-zst-generics.rs
+++ b/tests/ui/transmute/transmute-zst-generics.rs
@@ -24,11 +24,21 @@ unsafe fn cast_zst3<T>(from: ()) -> [[T; 0]; 8] {
     ::std::mem::transmute::<(), [[T; 0]; 8]>(from)
 }
 
+// Verify transmute with an extra ZST field
+pub struct PtrAndZst<T: ?Sized> {
+    _inner: *mut T,
+    _other: (),
+}
+pub unsafe fn cast_ptr<T: ?Sized>(from: *mut T) -> PtrAndZst<T> {
+    std::mem::transmute(from)
+}
+
 pub fn main() {
     unsafe {
         let _: [u32; 0] = cast_zst0(());
         let _ = cast_zst1::<u32>([]);
         let _: [(u32, u32); 0] = cast_zst2(());
         let _: [[u32; 0]; 8] = cast_zst3(());
+        cast_ptr(&mut 42);
     };
 }