Merging upstream version 1.68.2+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

4 files changed, 188 insertions, 0 deletions

diff --git a/tests/ui/transmutability/unions/repr/should_handle_align.rs b/tests/ui/transmutability/unions/repr/should_handle_align.rs
new file mode 100644
index 000000000..09c13cc4d
--- /dev/null
+++ b/tests/ui/transmutability/unions/repr/should_handle_align.rs
@@ -0,0 +1,47 @@
+// check-pass
+//! The presence of an `align(X)` annotation must be accounted for.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code, incomplete_features, non_camel_case_types)]
+
+mod assert {
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
+    pub struct Context;
+
+    pub fn is_maybe_transmutable<Src, Dst>()
+    where
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
+    {}
+}
+
+fn should_pad_explicitly_aligned_field() {
+    #[derive(Clone, Copy)] #[repr(u8)] enum V0u8 { V = 0 }
+    #[derive(Clone, Copy)] #[repr(u8)] enum V1u8 { V = 1 }
+
+    #[repr(C)]
+    pub union Uninit {
+        a: (),
+        b: V1u8,
+    }
+
+    #[repr(C, align(2))]
+    pub union align_2 {
+        a: V0u8,
+    }
+
+    #[repr(C)] struct ImplicitlyPadded(align_2, V0u8);
+    #[repr(C)] struct ExplicitlyPadded(V0u8, Uninit, V0u8);
+
+    // An implementation that (incorrectly) does not place a padding byte after
+    // `align_2` will, incorrectly, reject the following transmutations.
+    assert::is_maybe_transmutable::<ImplicitlyPadded, ExplicitlyPadded>();
+    assert::is_maybe_transmutable::<ExplicitlyPadded, ImplicitlyPadded>();
+}
diff --git a/tests/ui/transmutability/unions/repr/should_handle_packed.rs b/tests/ui/transmutability/unions/repr/should_handle_packed.rs
new file mode 100644
index 000000000..24c2abd69
--- /dev/null
+++ b/tests/ui/transmutability/unions/repr/should_handle_packed.rs
@@ -0,0 +1,48 @@
+// check-pass
+//! The presence of an `align(X)` annotation must be accounted for.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code, incomplete_features, non_camel_case_types)]
+
+mod assert {
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
+    pub struct Context;
+
+    pub fn is_maybe_transmutable<Src, Dst>()
+    where
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
+    {}
+}
+
+fn should_pad_explicitly_packed_field() {
+    #[derive(Clone, Copy)] #[repr(u8)] enum V0u8 { V = 0 }
+    #[derive(Clone, Copy)] #[repr(u8)] enum V1u8 { V = 1 }
+    #[derive(Clone, Copy)] #[repr(u8)] enum V2u8 { V = 2 }
+    #[derive(Clone, Copy)] #[repr(u32)] enum V3u32 { V = 3 }
+
+    #[repr(C)]
+    pub union Uninit {
+        a: (),
+        b: V1u8,
+    }
+
+    #[repr(C, packed(2))]
+    pub union Packed {
+        a: [V3u32; 0],
+        b: V0u8,
+    }
+
+    #[repr(C)] struct ImplicitlyPadded(Packed, V2u8);
+    #[repr(C)] struct ExplicitlyPadded(V0u8, Uninit, V2u8);
+
+    assert::is_maybe_transmutable::<ImplicitlyPadded, ExplicitlyPadded>();
+    assert::is_maybe_transmutable::<ExplicitlyPadded, ImplicitlyPadded>();
+}
diff --git a/tests/ui/transmutability/unions/repr/should_require_well_defined_layout.rs b/tests/ui/transmutability/unions/repr/should_require_well_defined_layout.rs
new file mode 100644
index 000000000..b1d5f71dc
--- /dev/null
+++ b/tests/ui/transmutability/unions/repr/should_require_well_defined_layout.rs
@@ -0,0 +1,44 @@
+//! A struct must have a well-defined layout to participate in a transmutation.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code, incomplete_features, non_camel_case_types)]
+
+mod assert {
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
+    pub struct Context;
+
+    pub fn is_maybe_transmutable<Src, Dst>()
+    where
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
+    {}
+}
+
+fn should_reject_repr_rust()
+{
+    union repr_rust {
+        a: u8
+    }
+
+    assert::is_maybe_transmutable::<repr_rust, ()>(); //~ ERROR cannot be safely transmuted
+    assert::is_maybe_transmutable::<u128, repr_rust>(); //~ ERROR cannot be safely transmuted
+}
+
+fn should_accept_repr_C()
+{
+    #[repr(C)]
+    union repr_c {
+        a: u8
+    }
+
+    struct repr_rust;
+    assert::is_maybe_transmutable::<repr_c, ()>();
+    assert::is_maybe_transmutable::<u128, repr_c>();
+}
diff --git a/tests/ui/transmutability/unions/repr/should_require_well_defined_layout.stderr b/tests/ui/transmutability/unions/repr/should_require_well_defined_layout.stderr
new file mode 100644
index 000000000..523bde85a
--- /dev/null
+++ b/tests/ui/transmutability/unions/repr/should_require_well_defined_layout.stderr
@@ -0,0 +1,49 @@
+error[E0277]: `should_reject_repr_rust::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+  --> $DIR/should_require_well_defined_layout.rs:30:48
+   |
+LL |     assert::is_maybe_transmutable::<repr_rust, ()>();
+   |                                                ^^ `should_reject_repr_rust::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+   |
+   = help: the trait `BikeshedIntrinsicFrom<should_reject_repr_rust::repr_rust, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
+note: required by a bound in `is_maybe_transmutable`
+  --> $DIR/should_require_well_defined_layout.rs:13:14
+   |
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `u128` cannot be safely transmuted into `should_reject_repr_rust::repr_rust` in the defining scope of `assert::Context`.
+  --> $DIR/should_require_well_defined_layout.rs:31:43
+   |
+LL |     assert::is_maybe_transmutable::<u128, repr_rust>();
+   |                                           ^^^^^^^^^ `u128` cannot be safely transmuted into `should_reject_repr_rust::repr_rust` in the defining scope of `assert::Context`.
+   |
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `should_reject_repr_rust::repr_rust`
+note: required by a bound in `is_maybe_transmutable`
+  --> $DIR/should_require_well_defined_layout.rs:13:14
+   |
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0277`.