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-rw-r--r--src/test/ui/transmutability/abstraction/abstracted_assume.rs73
-rw-r--r--src/test/ui/transmutability/abstraction/const_generic_fn.rs41
-rw-r--r--src/test/ui/transmutability/arrays/should_have_correct_length.rs44
-rw-r--r--src/test/ui/transmutability/arrays/should_inherit_alignment.rs55
-rw-r--r--src/test/ui/transmutability/arrays/should_require_well_defined_layout.rs61
-rw-r--r--src/test/ui/transmutability/arrays/should_require_well_defined_layout.stderr99
-rw-r--r--src/test/ui/transmutability/enums/repr/primitive_reprs_should_have_correct_length.rs149
-rw-r--r--src/test/ui/transmutability/enums/repr/primitive_reprs_should_have_correct_length.stderr323
-rw-r--r--src/test/ui/transmutability/enums/repr/should_require_well_defined_layout.rs117
-rw-r--r--src/test/ui/transmutability/enums/repr/should_require_well_defined_layout.stderr99
-rw-r--r--src/test/ui/transmutability/enums/should_order_correctly.rs32
-rw-r--r--src/test/ui/transmutability/enums/should_pad_variants.rs40
-rw-r--r--src/test/ui/transmutability/enums/should_pad_variants.stderr19
-rw-r--r--src/test/ui/transmutability/enums/should_respect_endianness.rs33
-rw-r--r--src/test/ui/transmutability/enums/should_respect_endianness.stderr19
-rw-r--r--src/test/ui/transmutability/malformed-program-gracefulness/feature-missing.rs9
-rw-r--r--src/test/ui/transmutability/malformed-program-gracefulness/feature-missing.stderr21
-rw-r--r--src/test/ui/transmutability/malformed-program-gracefulness/unknown_dst.rs21
-rw-r--r--src/test/ui/transmutability/malformed-program-gracefulness/unknown_dst.stderr12
-rw-r--r--src/test/ui/transmutability/malformed-program-gracefulness/unknown_src.rs21
-rw-r--r--src/test/ui/transmutability/malformed-program-gracefulness/unknown_src.stderr12
-rw-r--r--src/test/ui/transmutability/malformed-program-gracefulness/unknown_src_field.rs22
-rw-r--r--src/test/ui/transmutability/malformed-program-gracefulness/unknown_src_field.stderr9
-rw-r--r--src/test/ui/transmutability/malformed-program-gracefulness/wrong-type-assume.rs40
-rw-r--r--src/test/ui/transmutability/malformed-program-gracefulness/wrong-type-assume.stderr27
-rw-r--r--src/test/ui/transmutability/primitives/bool.rs25
-rw-r--r--src/test/ui/transmutability/primitives/bool.stderr19
-rw-r--r--src/test/ui/transmutability/primitives/numbers.rs128
-rw-r--r--src/test/ui/transmutability/primitives/numbers.stderr915
-rw-r--r--src/test/ui/transmutability/primitives/unit.rs24
-rw-r--r--src/test/ui/transmutability/primitives/unit.stderr19
-rw-r--r--src/test/ui/transmutability/references.rs20
-rw-r--r--src/test/ui/transmutability/references.stderr19
-rw-r--r--src/test/ui/transmutability/structs/repr/should_handle_align.rs36
-rw-r--r--src/test/ui/transmutability/structs/repr/should_handle_packed.rs35
-rw-r--r--src/test/ui/transmutability/structs/repr/should_require_well_defined_layout.rs76
-rw-r--r--src/test/ui/transmutability/structs/repr/should_require_well_defined_layout.stderr195
-rw-r--r--src/test/ui/transmutability/structs/should_order_fields_correctly.rs31
-rw-r--r--src/test/ui/transmutability/unions/boolish.rs31
-rw-r--r--src/test/ui/transmutability/unions/repr/should_handle_align.rs40
-rw-r--r--src/test/ui/transmutability/unions/repr/should_handle_packed.rs41
-rw-r--r--src/test/ui/transmutability/unions/repr/should_require_well_defined_layout.rs37
-rw-r--r--src/test/ui/transmutability/unions/repr/should_require_well_defined_layout.stderr35
-rw-r--r--src/test/ui/transmutability/unions/should_pad_variants.rs40
-rw-r--r--src/test/ui/transmutability/unions/should_pad_variants.stderr19
-rw-r--r--src/test/ui/transmutability/unions/should_permit_intersecting_if_validity_is_assumed.rs39
-rw-r--r--src/test/ui/transmutability/unions/should_reject_contraction.rs36
-rw-r--r--src/test/ui/transmutability/unions/should_reject_contraction.stderr19
-rw-r--r--src/test/ui/transmutability/unions/should_reject_disjoint.rs36
-rw-r--r--src/test/ui/transmutability/unions/should_reject_disjoint.stderr35
-rw-r--r--src/test/ui/transmutability/unions/should_reject_intersecting.rs38
-rw-r--r--src/test/ui/transmutability/unions/should_reject_intersecting.stderr35
-rw-r--r--src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_private_field.rs38
-rw-r--r--src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_private_variant.rs39
-rw-r--r--src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_tricky_unreachable_field.rs46
-rw-r--r--src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_field.rs39
-rw-r--r--src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_field.stderr12
-rw-r--r--src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_ty.rs40
-rw-r--r--src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_ty.stderr15
-rw-r--r--src/test/ui/transmutability/visibility/should_accept_if_src_has_private_field.rs38
-rw-r--r--src/test/ui/transmutability/visibility/should_accept_if_src_has_private_variant.rs39
-rw-r--r--src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_field.rs38
-rw-r--r--src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_field.stderr12
-rw-r--r--src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_ty.rs39
-rw-r--r--src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_ty.stderr15
-rw-r--r--src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_field.rs37
-rw-r--r--src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_field.stderr19
-rw-r--r--src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_variant.rs38
-rw-r--r--src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_variant.stderr19
-rw-r--r--src/test/ui/transmutability/visibility/should_reject_if_dst_has_tricky_unreachable_field.rs52
-rw-r--r--src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_field.rs39
-rw-r--r--src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_field.stderr19
-rw-r--r--src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_ty.rs42
-rw-r--r--src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_ty.stderr32
74 files changed, 4128 insertions, 0 deletions
diff --git a/src/test/ui/transmutability/abstraction/abstracted_assume.rs b/src/test/ui/transmutability/abstraction/abstracted_assume.rs
new file mode 100644
index 000000000..2abbbf3c1
--- /dev/null
+++ b/src/test/ui/transmutability/abstraction/abstracted_assume.rs
@@ -0,0 +1,73 @@
+// check-pass
+//! The implementation should behave correctly when the `ASSUME` parameters are
+//! provided indirectly through an abstraction.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code, incomplete_features, non_camel_case_types)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+
+ pub fn is_transmutable<
+ Src,
+ Dst,
+ Context,
+ const ASSUME_ALIGNMENT: bool,
+ const ASSUME_LIFETIMES: bool,
+ const ASSUME_VALIDITY: bool,
+ const ASSUME_VISIBILITY: bool,
+ >()
+ where
+ Dst: BikeshedIntrinsicFrom<
+ Src,
+ Context,
+ ASSUME_ALIGNMENT,
+ ASSUME_LIFETIMES,
+ ASSUME_VALIDITY,
+ ASSUME_VISIBILITY,
+ >,
+ {}
+}
+
+fn direct() {
+ struct Context;
+ #[repr(C)] struct Src;
+ #[repr(C)] struct Dst;
+
+ assert::is_transmutable::<Src, Dst, Context, false, false, false, false>();
+}
+
+fn via_const() {
+ struct Context;
+ #[repr(C)] struct Src;
+ #[repr(C)] struct Dst;
+
+ const FALSE: bool = false;
+
+ assert::is_transmutable::<Src, Dst, Context, FALSE, FALSE, FALSE, FALSE>();
+}
+
+fn via_associated_const() {
+ struct Context;
+ #[repr(C)] struct Src;
+ #[repr(C)] struct Dst;
+
+ trait Trait {
+ const FALSE: bool = true;
+ }
+
+ struct Ty;
+
+ impl Trait for Ty {}
+
+ assert::is_transmutable::<
+ Src,
+ Dst,
+ Context,
+ {Ty::FALSE},
+ {Ty::FALSE},
+ {Ty::FALSE},
+ {Ty::FALSE}
+ >();
+}
diff --git a/src/test/ui/transmutability/abstraction/const_generic_fn.rs b/src/test/ui/transmutability/abstraction/const_generic_fn.rs
new file mode 100644
index 000000000..94c38bb28
--- /dev/null
+++ b/src/test/ui/transmutability/abstraction/const_generic_fn.rs
@@ -0,0 +1,41 @@
+// check-pass
+//! An array must have the correct length.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code, incomplete_features, non_camel_case_types)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn array_like<T, E, const N: usize>()
+ where
+ T: BikeshedIntrinsicFrom<[E; N], Context, false, false, false, true>,
+ [E; N]: BikeshedIntrinsicFrom<T, Context, false, false, false, true>
+ {}
+}
+
+fn len_0() {
+ type Array = [u8; 0];
+ #[repr(C)] struct Struct();
+ assert::array_like::<Struct, u8, 0>();
+}
+
+fn len_1() {
+ type Array = [u8; 1];
+ #[repr(C)] struct Struct(u8);
+ assert::array_like::<Struct, u8, 1>();
+}
+
+fn len_2() {
+ type Array = [u8; 2];
+ #[repr(C)] struct Struct(u8, u8);
+ assert::array_like::<Struct, u8, 2>();
+}
+
+fn len_3() {
+ type Array = [u8; 3];
+ #[repr(C)] struct Struct(u8, u8, u8);
+ assert::array_like::<Struct, u8, 3>();
+}
diff --git a/src/test/ui/transmutability/arrays/should_have_correct_length.rs b/src/test/ui/transmutability/arrays/should_have_correct_length.rs
new file mode 100644
index 000000000..bfe6d830a
--- /dev/null
+++ b/src/test/ui/transmutability/arrays/should_have_correct_length.rs
@@ -0,0 +1,44 @@
+// check-pass
+//! An array must have the correct length.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code, incomplete_features, non_camel_case_types)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_maybe_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ {}
+}
+
+fn should_have_len_0() {
+ type Array = [u8; 0];
+ #[repr(C)] struct Struct();
+ assert::is_maybe_transmutable::<Array, Struct>();
+ assert::is_maybe_transmutable::<Struct, Array>();
+}
+
+fn should_have_len_1() {
+ type Array = [u8; 1];
+ #[repr(C)] struct Struct(u8);
+ assert::is_maybe_transmutable::<Array, Struct>();
+ assert::is_maybe_transmutable::<Struct, Array>();
+}
+
+fn should_have_len_2() {
+ type Array = [u8; 2];
+ #[repr(C)] struct Struct(u8, u8);
+ assert::is_maybe_transmutable::<Array, Struct>();
+ assert::is_maybe_transmutable::<Struct, Array>();
+}
+
+fn should_have_len_3() {
+ type Array = [u8; 3];
+ #[repr(C)] struct Struct(u8, u8, u8);
+ assert::is_maybe_transmutable::<Array, Struct>();
+ assert::is_maybe_transmutable::<Struct, Array>();
+}
diff --git a/src/test/ui/transmutability/arrays/should_inherit_alignment.rs b/src/test/ui/transmutability/arrays/should_inherit_alignment.rs
new file mode 100644
index 000000000..fcb1765ea
--- /dev/null
+++ b/src/test/ui/transmutability/arrays/should_inherit_alignment.rs
@@ -0,0 +1,55 @@
+// check-pass
+//! An array must inherit the alignment of its inner type.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code, incomplete_features, non_camel_case_types)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_maybe_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ {}
+}
+
+#[derive(Clone, Copy)] #[repr(u8)] enum Ox00 { V = 0x00 }
+#[derive(Clone, Copy)] #[repr(u8)] enum Ox01 { V = 0x01 }
+#[derive(Clone, Copy)] #[repr(u8)] enum OxFF { V = 0xFF }
+
+#[repr(C)]
+union Uninit {
+ a: (),
+ b: OxFF,
+}
+
+#[repr(C, align(2))] struct align_2(Ox00);
+
+fn len_0() {
+ #[repr(C)] struct ImplicitlyPadded([align_2; 0], Ox01);
+ #[repr(C)] struct ExplicitlyPadded(Ox01, Uninit);
+
+ #[repr(C)] struct Struct();
+ assert::is_maybe_transmutable::<ImplicitlyPadded, ExplicitlyPadded>();
+ assert::is_maybe_transmutable::<ExplicitlyPadded, ImplicitlyPadded>();
+}
+
+fn len_1() {
+ #[repr(C)] struct ImplicitlyPadded([align_2; 1], Ox01);
+ #[repr(C)] struct ExplicitlyPadded(Ox00, Uninit, Ox01, Uninit);
+
+ #[repr(C)] struct Struct();
+ assert::is_maybe_transmutable::<ImplicitlyPadded, ExplicitlyPadded>();
+ assert::is_maybe_transmutable::<ExplicitlyPadded, ImplicitlyPadded>();
+}
+
+fn len_2() {
+ #[repr(C)] struct ImplicitlyPadded([align_2; 2], Ox01);
+ #[repr(C)] struct ExplicitlyPadded(Ox00, Uninit, Ox00, Uninit, Ox01, Uninit);
+
+ #[repr(C)] struct Struct();
+ assert::is_maybe_transmutable::<ImplicitlyPadded, ExplicitlyPadded>();
+ assert::is_maybe_transmutable::<ExplicitlyPadded, ImplicitlyPadded>();
+}
diff --git a/src/test/ui/transmutability/arrays/should_require_well_defined_layout.rs b/src/test/ui/transmutability/arrays/should_require_well_defined_layout.rs
new file mode 100644
index 000000000..8e69527c1
--- /dev/null
+++ b/src/test/ui/transmutability/arrays/should_require_well_defined_layout.rs
@@ -0,0 +1,61 @@
+//! An array 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::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_maybe_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ {}
+}
+
+fn should_reject_repr_rust()
+{
+ fn unit() {
+ type repr_rust = [String; 0];
+ assert::is_maybe_transmutable::<repr_rust, ()>(); //~ ERROR cannot be safely transmuted
+ assert::is_maybe_transmutable::<u128, repr_rust>(); //~ ERROR cannot be safely transmuted
+ }
+
+ fn singleton() {
+ type repr_rust = [String; 1];
+ assert::is_maybe_transmutable::<repr_rust, ()>(); //~ ERROR cannot be safely transmuted
+ assert::is_maybe_transmutable::<u128, repr_rust>(); //~ ERROR cannot be safely transmuted
+ }
+
+ fn duplex() {
+ type repr_rust = [String; 2];
+ 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()
+{
+ fn unit() {
+ #[repr(C)] struct repr_c(u8, u16, u8);
+ type array = [repr_c; 0];
+ assert::is_maybe_transmutable::<array, ()>();
+ assert::is_maybe_transmutable::<i128, array>();
+ }
+
+ fn singleton() {
+ #[repr(C)] struct repr_c(u8, u16, u8);
+ type array = [repr_c; 1];
+ assert::is_maybe_transmutable::<array, repr_c>();
+ assert::is_maybe_transmutable::<repr_c, array>();
+ }
+
+ fn duplex() {
+ #[repr(C)] struct repr_c(u8, u16, u8);
+ #[repr(C)] struct duplex(repr_c, repr_c);
+ type array = [repr_c; 2];
+ assert::is_maybe_transmutable::<array, duplex>();
+ assert::is_maybe_transmutable::<duplex, array>();
+ }
+}
diff --git a/src/test/ui/transmutability/arrays/should_require_well_defined_layout.stderr b/src/test/ui/transmutability/arrays/should_require_well_defined_layout.stderr
new file mode 100644
index 000000000..eae0c947d
--- /dev/null
+++ b/src/test/ui/transmutability/arrays/should_require_well_defined_layout.stderr
@@ -0,0 +1,99 @@
+error[E0277]: `[String; 0]` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:21:52
+ |
+LL | assert::is_maybe_transmutable::<repr_rust, ()>();
+ | ^^ `[String; 0]` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<[String; 0], assert::Context, true, true, true, 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, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `u128` cannot be safely transmuted into `[String; 0]` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:22:47
+ |
+LL | assert::is_maybe_transmutable::<u128, repr_rust>();
+ | ^^^^^^^^^ `u128` cannot be safely transmuted into `[String; 0]` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `[String; 0]`
+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, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `[String; 1]` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:27:52
+ |
+LL | assert::is_maybe_transmutable::<repr_rust, ()>();
+ | ^^ `[String; 1]` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<[String; 1], assert::Context, true, true, true, 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, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `u128` cannot be safely transmuted into `[String; 1]` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:28:47
+ |
+LL | assert::is_maybe_transmutable::<u128, repr_rust>();
+ | ^^^^^^^^^ `u128` cannot be safely transmuted into `[String; 1]` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `[String; 1]`
+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, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `[String; 2]` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:33:52
+ |
+LL | assert::is_maybe_transmutable::<repr_rust, ()>();
+ | ^^ `[String; 2]` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<[String; 2], assert::Context, true, true, true, 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, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `u128` cannot be safely transmuted into `[String; 2]` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:34:47
+ |
+LL | assert::is_maybe_transmutable::<u128, repr_rust>();
+ | ^^^^^^^^^ `u128` cannot be safely transmuted into `[String; 2]` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `[String; 2]`
+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, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error: aborting due to 6 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/transmutability/enums/repr/primitive_reprs_should_have_correct_length.rs b/src/test/ui/transmutability/enums/repr/primitive_reprs_should_have_correct_length.rs
new file mode 100644
index 000000000..18e02b0d2
--- /dev/null
+++ b/src/test/ui/transmutability/enums/repr/primitive_reprs_should_have_correct_length.rs
@@ -0,0 +1,149 @@
+//! An enum with a primitive repr should have exactly the size of that primitive.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+
+ pub fn is_transmutable<Src, Dst, Context>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ {}
+}
+
+#[repr(C)]
+struct Zst;
+
+#[derive(Clone, Copy)]
+#[repr(i8)] enum V0i8 { V }
+#[repr(u8)] enum V0u8 { V }
+#[repr(i16)] enum V0i16 { V }
+#[repr(u16)] enum V0u16 { V }
+#[repr(i32)] enum V0i32 { V }
+#[repr(u32)] enum V0u32 { V }
+#[repr(i64)] enum V0i64 { V }
+#[repr(u64)] enum V0u64 { V }
+#[repr(isize)] enum V0isize { V }
+#[repr(usize)] enum V0usize { V }
+
+fn n8() {
+ struct Context;
+
+ type Smaller = Zst;
+ type Analog = u8;
+ type Larger = u16;
+
+ fn i_should_have_correct_length() {
+ type Current = V0i8;
+
+ assert::is_transmutable::<Smaller, Current, Context>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::<Current, Analog, Context>();
+ assert::is_transmutable::<Current, Larger, Context>(); //~ ERROR cannot be safely transmuted
+ }
+
+ fn u_should_have_correct_length() {
+ type Current = V0u8;
+
+ assert::is_transmutable::<Smaller, Current, Context>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::<Current, Analog, Context>();
+ assert::is_transmutable::<Current, Larger, Context>(); //~ ERROR cannot be safely transmuted
+ }
+}
+
+fn n16() {
+ struct Context;
+
+ type Smaller = u8;
+ type Analog = u16;
+ type Larger = u32;
+
+ fn i_should_have_correct_length() {
+ type Current = V0i16;
+
+ assert::is_transmutable::<Smaller, Current, Context>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::<Current, Analog, Context>();
+ assert::is_transmutable::<Current, Larger, Context>(); //~ ERROR cannot be safely transmuted
+ }
+
+ fn u_should_have_correct_length() {
+ type Current = V0u16;
+
+ assert::is_transmutable::<Smaller, Current, Context>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::<Current, Analog, Context>();
+ assert::is_transmutable::<Current, Larger, Context>(); //~ ERROR cannot be safely transmuted
+ }
+}
+
+fn n32() {
+ struct Context;
+
+ type Smaller = u16;
+ type Analog = u32;
+ type Larger = u64;
+
+ fn i_should_have_correct_length() {
+ type Current = V0i32;
+
+ assert::is_transmutable::<Smaller, Current, Context>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::<Current, Analog, Context>();
+ assert::is_transmutable::<Current, Larger, Context>(); //~ ERROR cannot be safely transmuted
+ }
+
+ fn u_should_have_correct_length() {
+ type Current = V0u32;
+
+ assert::is_transmutable::<Smaller, Current, Context>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::<Current, Analog, Context>();
+ assert::is_transmutable::<Current, Larger, Context>(); //~ ERROR cannot be safely transmuted
+ }
+}
+
+fn n64() {
+ struct Context;
+
+ type Smaller = u32;
+ type Analog = u64;
+ type Larger = u128;
+
+ fn i_should_have_correct_length() {
+ type Current = V0i64;
+
+ assert::is_transmutable::<Smaller, Current, Context>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::<Current, Analog, Context>();
+ assert::is_transmutable::<Current, Larger, Context>(); //~ ERROR cannot be safely transmuted
+ }
+
+ fn u_should_have_correct_length() {
+ type Current = V0u64;
+
+ assert::is_transmutable::<Smaller, Current, Context>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::<Current, Analog, Context>();
+ assert::is_transmutable::<Current, Larger, Context>(); //~ ERROR cannot be safely transmuted
+ }
+}
+
+fn nsize() {
+ struct Context;
+
+ type Smaller = u8;
+ type Analog = usize;
+ type Larger = [usize; 2];
+
+ fn i_should_have_correct_length() {
+ type Current = V0isize;
+
+ assert::is_transmutable::<Smaller, Current, Context>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::<Current, Analog, Context>();
+ assert::is_transmutable::<Current, Larger, Context>(); //~ ERROR cannot be safely transmuted
+ }
+
+ fn u_should_have_correct_length() {
+ type Current = V0usize;
+
+ assert::is_transmutable::<Smaller, Current, Context>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::<Current, Analog, Context>();
+ assert::is_transmutable::<Current, Larger, Context>(); //~ ERROR cannot be safely transmuted
+ }
+}
diff --git a/src/test/ui/transmutability/enums/repr/primitive_reprs_should_have_correct_length.stderr b/src/test/ui/transmutability/enums/repr/primitive_reprs_should_have_correct_length.stderr
new file mode 100644
index 000000000..fa2e3b89b
--- /dev/null
+++ b/src/test/ui/transmutability/enums/repr/primitive_reprs_should_have_correct_length.stderr
@@ -0,0 +1,323 @@
+error[E0277]: `Zst` cannot be safely transmuted into `V0i8` in the defining scope of `n8::Context`.
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:41:44
+ |
+LL | assert::is_transmutable::<Smaller, Current, Context>();
+ | ^^^^^^^ `Zst` cannot be safely transmuted into `V0i8` in the defining scope of `n8::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<Zst, n8::Context, true, true, true, true>` is not implemented for `V0i8`
+note: required by a bound in `is_transmutable`
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `V0i8` cannot be safely transmuted into `u16` in the defining scope of `n8::Context`.
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:43:44
+ |
+LL | assert::is_transmutable::<Current, Larger, Context>();
+ | ^^^^^^ `V0i8` cannot be safely transmuted into `u16` in the defining scope of `n8::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<V0i8, n8::Context, true, true, true, true>` is not implemented for `u16`
+note: required by a bound in `is_transmutable`
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `Zst` cannot be safely transmuted into `V0u8` in the defining scope of `n8::Context`.
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:49:44
+ |
+LL | assert::is_transmutable::<Smaller, Current, Context>();
+ | ^^^^^^^ `Zst` cannot be safely transmuted into `V0u8` in the defining scope of `n8::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<Zst, n8::Context, true, true, true, true>` is not implemented for `V0u8`
+note: required by a bound in `is_transmutable`
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `V0u8` cannot be safely transmuted into `u16` in the defining scope of `n8::Context`.
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:51:44
+ |
+LL | assert::is_transmutable::<Current, Larger, Context>();
+ | ^^^^^^ `V0u8` cannot be safely transmuted into `u16` in the defining scope of `n8::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<V0u8, n8::Context, true, true, true, true>` is not implemented for `u16`
+note: required by a bound in `is_transmutable`
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u8` cannot be safely transmuted into `V0i16` in the defining scope of `n16::Context`.
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:65:44
+ |
+LL | assert::is_transmutable::<Smaller, Current, Context>();
+ | ^^^^^^^ `u8` cannot be safely transmuted into `V0i16` in the defining scope of `n16::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u8, n16::Context, true, true, true, true>` is not implemented for `V0i16`
+note: required by a bound in `is_transmutable`
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `V0i16` cannot be safely transmuted into `u32` in the defining scope of `n16::Context`.
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:67:44
+ |
+LL | assert::is_transmutable::<Current, Larger, Context>();
+ | ^^^^^^ `V0i16` cannot be safely transmuted into `u32` in the defining scope of `n16::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<V0i16, n16::Context, true, true, true, true>` is not implemented for `u32`
+note: required by a bound in `is_transmutable`
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u8` cannot be safely transmuted into `V0u16` in the defining scope of `n16::Context`.
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:73:44
+ |
+LL | assert::is_transmutable::<Smaller, Current, Context>();
+ | ^^^^^^^ `u8` cannot be safely transmuted into `V0u16` in the defining scope of `n16::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u8, n16::Context, true, true, true, true>` is not implemented for `V0u16`
+note: required by a bound in `is_transmutable`
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `V0u16` cannot be safely transmuted into `u32` in the defining scope of `n16::Context`.
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:75:44
+ |
+LL | assert::is_transmutable::<Current, Larger, Context>();
+ | ^^^^^^ `V0u16` cannot be safely transmuted into `u32` in the defining scope of `n16::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<V0u16, n16::Context, true, true, true, true>` is not implemented for `u32`
+note: required by a bound in `is_transmutable`
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u16` cannot be safely transmuted into `V0i32` in the defining scope of `n32::Context`.
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:89:44
+ |
+LL | assert::is_transmutable::<Smaller, Current, Context>();
+ | ^^^^^^^ `u16` cannot be safely transmuted into `V0i32` in the defining scope of `n32::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u16, n32::Context, true, true, true, true>` is not implemented for `V0i32`
+note: required by a bound in `is_transmutable`
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `V0i32` cannot be safely transmuted into `u64` in the defining scope of `n32::Context`.
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:91:44
+ |
+LL | assert::is_transmutable::<Current, Larger, Context>();
+ | ^^^^^^ `V0i32` cannot be safely transmuted into `u64` in the defining scope of `n32::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<V0i32, n32::Context, true, true, true, true>` is not implemented for `u64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u16` cannot be safely transmuted into `V0u32` in the defining scope of `n32::Context`.
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:97:44
+ |
+LL | assert::is_transmutable::<Smaller, Current, Context>();
+ | ^^^^^^^ `u16` cannot be safely transmuted into `V0u32` in the defining scope of `n32::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u16, n32::Context, true, true, true, true>` is not implemented for `V0u32`
+note: required by a bound in `is_transmutable`
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `V0u32` cannot be safely transmuted into `u64` in the defining scope of `n32::Context`.
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:99:44
+ |
+LL | assert::is_transmutable::<Current, Larger, Context>();
+ | ^^^^^^ `V0u32` cannot be safely transmuted into `u64` in the defining scope of `n32::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<V0u32, n32::Context, true, true, true, true>` is not implemented for `u64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u32` cannot be safely transmuted into `V0i64` in the defining scope of `n64::Context`.
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:113:44
+ |
+LL | assert::is_transmutable::<Smaller, Current, Context>();
+ | ^^^^^^^ `u32` cannot be safely transmuted into `V0i64` in the defining scope of `n64::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u32, n64::Context, true, true, true, true>` is not implemented for `V0i64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `V0i64` cannot be safely transmuted into `u128` in the defining scope of `n64::Context`.
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:115:44
+ |
+LL | assert::is_transmutable::<Current, Larger, Context>();
+ | ^^^^^^ `V0i64` cannot be safely transmuted into `u128` in the defining scope of `n64::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<V0i64, n64::Context, true, true, true, true>` is not implemented for `u128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u32` cannot be safely transmuted into `V0u64` in the defining scope of `n64::Context`.
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:121:44
+ |
+LL | assert::is_transmutable::<Smaller, Current, Context>();
+ | ^^^^^^^ `u32` cannot be safely transmuted into `V0u64` in the defining scope of `n64::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u32, n64::Context, true, true, true, true>` is not implemented for `V0u64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `V0u64` cannot be safely transmuted into `u128` in the defining scope of `n64::Context`.
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:123:44
+ |
+LL | assert::is_transmutable::<Current, Larger, Context>();
+ | ^^^^^^ `V0u64` cannot be safely transmuted into `u128` in the defining scope of `n64::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<V0u64, n64::Context, true, true, true, true>` is not implemented for `u128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u8` cannot be safely transmuted into `V0isize` in the defining scope of `nsize::Context`.
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:137:44
+ |
+LL | assert::is_transmutable::<Smaller, Current, Context>();
+ | ^^^^^^^ `u8` cannot be safely transmuted into `V0isize` in the defining scope of `nsize::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u8, nsize::Context, true, true, true, true>` is not implemented for `V0isize`
+note: required by a bound in `is_transmutable`
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `V0isize` cannot be safely transmuted into `[usize; 2]` in the defining scope of `nsize::Context`.
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:139:44
+ |
+LL | assert::is_transmutable::<Current, Larger, Context>();
+ | ^^^^^^ `V0isize` cannot be safely transmuted into `[usize; 2]` in the defining scope of `nsize::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<V0isize, nsize::Context, true, true, true, true>` is not implemented for `[usize; 2]`
+note: required by a bound in `is_transmutable`
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u8` cannot be safely transmuted into `V0usize` in the defining scope of `nsize::Context`.
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:145:44
+ |
+LL | assert::is_transmutable::<Smaller, Current, Context>();
+ | ^^^^^^^ `u8` cannot be safely transmuted into `V0usize` in the defining scope of `nsize::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u8, nsize::Context, true, true, true, true>` is not implemented for `V0usize`
+note: required by a bound in `is_transmutable`
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `V0usize` cannot be safely transmuted into `[usize; 2]` in the defining scope of `nsize::Context`.
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:147:44
+ |
+LL | assert::is_transmutable::<Current, Larger, Context>();
+ | ^^^^^^ `V0usize` cannot be safely transmuted into `[usize; 2]` in the defining scope of `nsize::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<V0usize, nsize::Context, true, true, true, true>` is not implemented for `[usize; 2]`
+note: required by a bound in `is_transmutable`
+ --> $DIR/primitive_reprs_should_have_correct_length.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error: aborting due to 20 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/transmutability/enums/repr/should_require_well_defined_layout.rs b/src/test/ui/transmutability/enums/repr/should_require_well_defined_layout.rs
new file mode 100644
index 000000000..978a12648
--- /dev/null
+++ b/src/test/ui/transmutability/enums/repr/should_require_well_defined_layout.rs
@@ -0,0 +1,117 @@
+//! An enum must have a well-defined layout to participate in a transmutation.
+
+#![crate_type = "lib"]
+#![feature(repr128)]
+#![feature(transmutability)]
+#![allow(dead_code, incomplete_features, non_camel_case_types)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_maybe_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ {}
+}
+
+fn should_reject_repr_rust() {
+ fn void() {
+ enum repr_rust {}
+ assert::is_maybe_transmutable::<repr_rust, ()>(); //~ ERROR cannot be safely transmuted
+ assert::is_maybe_transmutable::<u128, repr_rust>(); //~ ERROR cannot be safely transmuted
+ }
+
+ fn singleton() {
+ enum repr_rust { V }
+ assert::is_maybe_transmutable::<repr_rust, ()>(); //~ ERROR cannot be safely transmuted
+ assert::is_maybe_transmutable::<u128, repr_rust>(); //~ ERROR cannot be safely transmuted
+ }
+
+ fn duplex() {
+ enum repr_rust { A, B }
+ 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_primitive_reprs()
+{
+ fn should_accept_repr_i8() {
+ #[repr(i8)] enum repr_i8 { V }
+ assert::is_maybe_transmutable::<repr_i8, ()>();
+ assert::is_maybe_transmutable::<i8, repr_i8>();
+ }
+
+ fn should_accept_repr_u8() {
+ #[repr(u8)] enum repr_u8 { V }
+ assert::is_maybe_transmutable::<repr_u8, ()>();
+ assert::is_maybe_transmutable::<u8, repr_u8>();
+ }
+
+ fn should_accept_repr_i16() {
+ #[repr(i16)] enum repr_i16 { V }
+ assert::is_maybe_transmutable::<repr_i16, ()>();
+ assert::is_maybe_transmutable::<i16, repr_i16>();
+ }
+
+ fn should_accept_repr_u16() {
+ #[repr(u16)] enum repr_u16 { V }
+ assert::is_maybe_transmutable::<repr_u16, ()>();
+ assert::is_maybe_transmutable::<u16, repr_u16>();
+ }
+
+ fn should_accept_repr_i32() {
+ #[repr(i32)] enum repr_i32 { V }
+ assert::is_maybe_transmutable::<repr_i32, ()>();
+ assert::is_maybe_transmutable::<i32, repr_i32>();
+ }
+
+ fn should_accept_repr_u32() {
+ #[repr(u32)] enum repr_u32 { V }
+ assert::is_maybe_transmutable::<repr_u32, ()>();
+ assert::is_maybe_transmutable::<u32, repr_u32>();
+ }
+
+ fn should_accept_repr_i64() {
+ #[repr(i64)] enum repr_i64 { V }
+ assert::is_maybe_transmutable::<repr_i64, ()>();
+ assert::is_maybe_transmutable::<i64, repr_i64>();
+ }
+
+ fn should_accept_repr_u64() {
+ #[repr(u64)] enum repr_u64 { V }
+ assert::is_maybe_transmutable::<repr_u64, ()>();
+ assert::is_maybe_transmutable::<u64, repr_u64>();
+ }
+
+ fn should_accept_repr_i128() {
+ #[repr(i128)] enum repr_i128 { V }
+ assert::is_maybe_transmutable::<repr_i128, ()>();
+ assert::is_maybe_transmutable::<i128, repr_i128>();
+ }
+
+ fn should_accept_repr_u128() {
+ #[repr(u128)] enum repr_u128 { V }
+ assert::is_maybe_transmutable::<repr_u128, ()>();
+ assert::is_maybe_transmutable::<u128, repr_u128>();
+ }
+
+ fn should_accept_repr_isize() {
+ #[repr(isize)] enum repr_isize { V }
+ assert::is_maybe_transmutable::<repr_isize, ()>();
+ assert::is_maybe_transmutable::<isize, repr_isize>();
+ }
+
+ fn should_accept_repr_usize() {
+ #[repr(usize)] enum repr_usize { V }
+ assert::is_maybe_transmutable::<repr_usize, ()>();
+ assert::is_maybe_transmutable::<usize, repr_usize>();
+ }
+}
+
+fn should_accept_repr_C() {
+ #[repr(C)] enum repr_c { V }
+ assert::is_maybe_transmutable::<repr_c, ()>();
+ assert::is_maybe_transmutable::<i128, repr_c>();
+}
diff --git a/src/test/ui/transmutability/enums/repr/should_require_well_defined_layout.stderr b/src/test/ui/transmutability/enums/repr/should_require_well_defined_layout.stderr
new file mode 100644
index 000000000..3273e87c8
--- /dev/null
+++ b/src/test/ui/transmutability/enums/repr/should_require_well_defined_layout.stderr
@@ -0,0 +1,99 @@
+error[E0277]: `void::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:21:52
+ |
+LL | assert::is_maybe_transmutable::<repr_rust, ()>();
+ | ^^ `void::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<void::repr_rust, assert::Context, true, true, true, true>` is not implemented for `()`
+note: required by a bound in `is_maybe_transmutable`
+ --> $DIR/should_require_well_defined_layout.rs:14:14
+ |
+LL | pub fn is_maybe_transmutable<Src, Dst>()
+ | --------------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `u128` cannot be safely transmuted into `void::repr_rust` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:22:47
+ |
+LL | assert::is_maybe_transmutable::<u128, repr_rust>();
+ | ^^^^^^^^^ `u128` cannot be safely transmuted into `void::repr_rust` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `void::repr_rust`
+note: required by a bound in `is_maybe_transmutable`
+ --> $DIR/should_require_well_defined_layout.rs:14:14
+ |
+LL | pub fn is_maybe_transmutable<Src, Dst>()
+ | --------------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `singleton::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:27:52
+ |
+LL | assert::is_maybe_transmutable::<repr_rust, ()>();
+ | ^^ `singleton::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<singleton::repr_rust, assert::Context, true, true, true, true>` is not implemented for `()`
+note: required by a bound in `is_maybe_transmutable`
+ --> $DIR/should_require_well_defined_layout.rs:14:14
+ |
+LL | pub fn is_maybe_transmutable<Src, Dst>()
+ | --------------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `u128` cannot be safely transmuted into `singleton::repr_rust` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:28:47
+ |
+LL | assert::is_maybe_transmutable::<u128, repr_rust>();
+ | ^^^^^^^^^ `u128` cannot be safely transmuted into `singleton::repr_rust` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `singleton::repr_rust`
+note: required by a bound in `is_maybe_transmutable`
+ --> $DIR/should_require_well_defined_layout.rs:14:14
+ |
+LL | pub fn is_maybe_transmutable<Src, Dst>()
+ | --------------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `duplex::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:33:52
+ |
+LL | assert::is_maybe_transmutable::<repr_rust, ()>();
+ | ^^ `duplex::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<duplex::repr_rust, assert::Context, true, true, true, true>` is not implemented for `()`
+note: required by a bound in `is_maybe_transmutable`
+ --> $DIR/should_require_well_defined_layout.rs:14:14
+ |
+LL | pub fn is_maybe_transmutable<Src, Dst>()
+ | --------------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `u128` cannot be safely transmuted into `duplex::repr_rust` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:34:47
+ |
+LL | assert::is_maybe_transmutable::<u128, repr_rust>();
+ | ^^^^^^^^^ `u128` cannot be safely transmuted into `duplex::repr_rust` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `duplex::repr_rust`
+note: required by a bound in `is_maybe_transmutable`
+ --> $DIR/should_require_well_defined_layout.rs:14:14
+ |
+LL | pub fn is_maybe_transmutable<Src, Dst>()
+ | --------------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error: aborting due to 6 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/transmutability/enums/should_order_correctly.rs b/src/test/ui/transmutability/enums/should_order_correctly.rs
new file mode 100644
index 000000000..6558d2658
--- /dev/null
+++ b/src/test/ui/transmutability/enums/should_order_correctly.rs
@@ -0,0 +1,32 @@
+// check-pass
+//! The payloads of an enum variant should be ordered after its tag.
+
+#![crate_type = "lib"]
+#![feature(arbitrary_enum_discriminant)]
+#![feature(transmutability)]
+#![allow(dead_code)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ {}
+}
+
+#[repr(u8)] enum V0 { V = 0 }
+#[repr(u8)] enum V1 { V = 1 }
+#[repr(u8)] enum V2 { V = 2 }
+
+#[repr(u8)] enum E01 { V0(V1) = 0u8 }
+#[repr(u8)] enum E012 { V0(V1, V2) = 0u8 }
+
+fn should_order_tag_and_fields_correctly() {
+ // An implementation that (incorrectly) arranges E01 as [0x01, 0x00] will,
+ // in principle, reject this transmutation.
+ assert::is_transmutable::<E01, V0>();
+ // Again, but with one more field.
+ assert::is_transmutable::<E012, E01>();
+}
diff --git a/src/test/ui/transmutability/enums/should_pad_variants.rs b/src/test/ui/transmutability/enums/should_pad_variants.rs
new file mode 100644
index 000000000..466b6c8a1
--- /dev/null
+++ b/src/test/ui/transmutability/enums/should_pad_variants.rs
@@ -0,0 +1,40 @@
+//! The variants of an enum must be padded with uninit bytes such that they have
+//! the same length (in bytes).
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+
+ pub fn is_transmutable<Src, Dst, Context>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ {}
+}
+
+#[derive(Clone, Copy)]
+#[repr(C)] struct Zst;
+
+#[derive(Clone, Copy)]
+#[repr(u8)] enum V0 { V = 0 }
+
+#[derive(Clone, Copy)]
+#[repr(u8)] enum V2 { V = 2 }
+
+#[repr(C, u8)]
+enum Lopsided {
+ Smol(Zst),
+ Lorg(V0),
+}
+
+#[repr(C)] struct Src(V0, Zst, V2);
+#[repr(C)] struct Dst(Lopsided, V2);
+
+fn should_pad_variants() {
+ struct Context;
+ // If the implementation (incorrectly) fails to pad `Lopsided::Smol` with
+ // an uninitialized byte, this transmutation might be (wrongly) accepted:
+ assert::is_transmutable::<Src, Dst, Context>(); //~ ERROR cannot be safely transmuted
+}
diff --git a/src/test/ui/transmutability/enums/should_pad_variants.stderr b/src/test/ui/transmutability/enums/should_pad_variants.stderr
new file mode 100644
index 000000000..429f7211d
--- /dev/null
+++ b/src/test/ui/transmutability/enums/should_pad_variants.stderr
@@ -0,0 +1,19 @@
+error[E0277]: `Src` cannot be safely transmuted into `Dst` in the defining scope of `should_pad_variants::Context`.
+ --> $DIR/should_pad_variants.rs:39:36
+ |
+LL | assert::is_transmutable::<Src, Dst, Context>();
+ | ^^^ `Src` cannot be safely transmuted into `Dst` in the defining scope of `should_pad_variants::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<Src, should_pad_variants::Context, true, true, true, true>` is not implemented for `Dst`
+note: required by a bound in `is_transmutable`
+ --> $DIR/should_pad_variants.rs:13:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/transmutability/enums/should_respect_endianness.rs b/src/test/ui/transmutability/enums/should_respect_endianness.rs
new file mode 100644
index 000000000..67a3c4e94
--- /dev/null
+++ b/src/test/ui/transmutability/enums/should_respect_endianness.rs
@@ -0,0 +1,33 @@
+//! The target endianness should be a consideration in computing the layout of
+//! an enum with a multi-byte tag.
+
+#![crate_type = "lib"]
+#![feature(arbitrary_enum_discriminant)]
+#![feature(transmutability)]
+#![allow(dead_code)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ {}
+}
+
+#[repr(u16)] enum Src { V = 0xCAFE }
+
+#[repr(u8)] enum OxCA { V = 0xCA }
+#[repr(u8)] enum OxFE { V = 0xFE }
+
+#[cfg(target_endian = "big")] #[repr(C)] struct Expected(OxCA, OxFE);
+#[cfg(target_endian = "big")] #[repr(C)] struct Unexpected(OxFE, OxCA);
+
+#[cfg(target_endian = "little")] #[repr(C)] struct Expected(OxFE, OxCA);
+#[cfg(target_endian = "little")] #[repr(C)] struct Unexpected(OxCA, OxFE);
+
+fn should_respect_endianness() {
+ assert::is_transmutable::<Src, Expected>();
+ assert::is_transmutable::<Src, Unexpected>(); //~ ERROR cannot be safely transmuted
+}
diff --git a/src/test/ui/transmutability/enums/should_respect_endianness.stderr b/src/test/ui/transmutability/enums/should_respect_endianness.stderr
new file mode 100644
index 000000000..78023cb37
--- /dev/null
+++ b/src/test/ui/transmutability/enums/should_respect_endianness.stderr
@@ -0,0 +1,19 @@
+error[E0277]: `Src` cannot be safely transmuted into `Unexpected` in the defining scope of `assert::Context`.
+ --> $DIR/should_respect_endianness.rs:32:36
+ |
+LL | assert::is_transmutable::<Src, Unexpected>();
+ | ^^^^^^^^^^ `Src` cannot be safely transmuted into `Unexpected` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<Src, assert::Context, true, true, true, true>` is not implemented for `Unexpected`
+note: required by a bound in `is_transmutable`
+ --> $DIR/should_respect_endianness.rs:15:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/transmutability/malformed-program-gracefulness/feature-missing.rs b/src/test/ui/transmutability/malformed-program-gracefulness/feature-missing.rs
new file mode 100644
index 000000000..30c381745
--- /dev/null
+++ b/src/test/ui/transmutability/malformed-program-gracefulness/feature-missing.rs
@@ -0,0 +1,9 @@
+// The trait must not be available if its feature flag is absent.
+
+#![crate_type = "lib"]
+
+use std::mem::BikeshedIntrinsicFrom;
+//~^ ERROR use of unstable library feature 'transmutability' [E0658]
+
+use std::mem::Assume;
+//~^ ERROR use of unstable library feature 'transmutability' [E0658]
diff --git a/src/test/ui/transmutability/malformed-program-gracefulness/feature-missing.stderr b/src/test/ui/transmutability/malformed-program-gracefulness/feature-missing.stderr
new file mode 100644
index 000000000..ba8093f86
--- /dev/null
+++ b/src/test/ui/transmutability/malformed-program-gracefulness/feature-missing.stderr
@@ -0,0 +1,21 @@
+error[E0658]: use of unstable library feature 'transmutability'
+ --> $DIR/feature-missing.rs:5:5
+ |
+LL | use std::mem::BikeshedIntrinsicFrom;
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: see issue #99571 <https://github.com/rust-lang/rust/issues/99571> for more information
+ = help: add `#![feature(transmutability)]` to the crate attributes to enable
+
+error[E0658]: use of unstable library feature 'transmutability'
+ --> $DIR/feature-missing.rs:8:5
+ |
+LL | use std::mem::Assume;
+ | ^^^^^^^^^^^^^^^^
+ |
+ = note: see issue #99571 <https://github.com/rust-lang/rust/issues/99571> for more information
+ = help: add `#![feature(transmutability)]` to the crate attributes to enable
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/transmutability/malformed-program-gracefulness/unknown_dst.rs b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_dst.rs
new file mode 100644
index 000000000..e13462d39
--- /dev/null
+++ b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_dst.rs
@@ -0,0 +1,21 @@
+// An unknown destination type should be gracefully handled.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code, incomplete_features, non_camel_case_types)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_transmutable<Src, Dst, Context>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ {}
+}
+
+fn should_gracefully_handle_unknown_dst() {
+ struct Context;
+ struct Src;
+ assert::is_transmutable::<Src, Dst, Context>(); //~ cannot find type
+}
diff --git a/src/test/ui/transmutability/malformed-program-gracefulness/unknown_dst.stderr b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_dst.stderr
new file mode 100644
index 000000000..85087282d
--- /dev/null
+++ b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_dst.stderr
@@ -0,0 +1,12 @@
+error[E0412]: cannot find type `Dst` in this scope
+ --> $DIR/unknown_dst.rs:20:36
+ |
+LL | fn should_gracefully_handle_unknown_dst() {
+ | - help: you might be missing a type parameter: `<Dst>`
+...
+LL | assert::is_transmutable::<Src, Dst, Context>();
+ | ^^^ not found in this scope
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0412`.
diff --git a/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src.rs b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src.rs
new file mode 100644
index 000000000..dc51e2a8f
--- /dev/null
+++ b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src.rs
@@ -0,0 +1,21 @@
+// An unknown source type should be gracefully handled.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code, incomplete_features, non_camel_case_types)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_transmutable<Src, Dst, Context>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ {}
+}
+
+fn should_gracefully_handle_unknown_src() {
+ struct Context;
+ #[repr(C)] struct Dst;
+ assert::is_transmutable::<Src, Dst, Context>(); //~ cannot find type
+}
diff --git a/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src.stderr b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src.stderr
new file mode 100644
index 000000000..9bedbe87c
--- /dev/null
+++ b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src.stderr
@@ -0,0 +1,12 @@
+error[E0412]: cannot find type `Src` in this scope
+ --> $DIR/unknown_src.rs:20:31
+ |
+LL | fn should_gracefully_handle_unknown_src() {
+ | - help: you might be missing a type parameter: `<Src>`
+...
+LL | assert::is_transmutable::<Src, Dst, Context>();
+ | ^^^ not found in this scope
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0412`.
diff --git a/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src_field.rs b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src_field.rs
new file mode 100644
index 000000000..86fc8bd6b
--- /dev/null
+++ b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src_field.rs
@@ -0,0 +1,22 @@
+// An unknown destination type should be gracefully handled.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code, incomplete_features, non_camel_case_types)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_transmutable<Src, Dst, Context>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ {}
+}
+
+fn should_gracefully_handle_unknown_dst_field() {
+ struct Context;
+ #[repr(C)] struct Src;
+ #[repr(C)] struct Dst(Missing); //~ cannot find type
+ assert::is_transmutable::<Src, Dst, Context>();
+}
diff --git a/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src_field.stderr b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src_field.stderr
new file mode 100644
index 000000000..475e6f429
--- /dev/null
+++ b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src_field.stderr
@@ -0,0 +1,9 @@
+error[E0412]: cannot find type `Missing` in this scope
+ --> $DIR/unknown_src_field.rs:20:27
+ |
+LL | #[repr(C)] struct Dst(Missing);
+ | ^^^^^^^ not found in this scope
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0412`.
diff --git a/src/test/ui/transmutability/malformed-program-gracefulness/wrong-type-assume.rs b/src/test/ui/transmutability/malformed-program-gracefulness/wrong-type-assume.rs
new file mode 100644
index 000000000..bd36748e7
--- /dev/null
+++ b/src/test/ui/transmutability/malformed-program-gracefulness/wrong-type-assume.rs
@@ -0,0 +1,40 @@
+//! The implementation must behave well if const values of wrong types are
+//! provided.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code, incomplete_features, non_camel_case_types)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+
+ pub fn is_transmutable<
+ Src,
+ Dst,
+ Context,
+ const ASSUME_ALIGNMENT: bool,
+ const ASSUME_LIFETIMES: bool,
+ const ASSUME_VALIDITY: bool,
+ const ASSUME_VISIBILITY: bool,
+ >()
+ where
+ Dst: BikeshedIntrinsicFrom<
+ Src,
+ Context,
+ ASSUME_ALIGNMENT,
+ ASSUME_LIFETIMES,
+ ASSUME_VALIDITY,
+ ASSUME_VISIBILITY,
+ >,
+ {}
+}
+
+fn test() {
+ struct Context;
+ #[repr(C)] struct Src;
+ #[repr(C)] struct Dst;
+ assert::is_transmutable::<Src, Dst, Context, {0u8}, false, false, false>(); //~ ERROR mismatched types
+ assert::is_transmutable::<Src, Dst, Context, false, {0u8}, false, false>(); //~ ERROR mismatched types
+ assert::is_transmutable::<Src, Dst, Context, false, false, {0u8}, false>(); //~ ERROR mismatched types
+ assert::is_transmutable::<Src, Dst, Context, false, false, false, {0u8}>(); //~ ERROR mismatched types
+}
diff --git a/src/test/ui/transmutability/malformed-program-gracefulness/wrong-type-assume.stderr b/src/test/ui/transmutability/malformed-program-gracefulness/wrong-type-assume.stderr
new file mode 100644
index 000000000..e1464e023
--- /dev/null
+++ b/src/test/ui/transmutability/malformed-program-gracefulness/wrong-type-assume.stderr
@@ -0,0 +1,27 @@
+error[E0308]: mismatched types
+ --> $DIR/wrong-type-assume.rs:36:51
+ |
+LL | assert::is_transmutable::<Src, Dst, Context, {0u8}, false, false, false>();
+ | ^^^ expected `bool`, found `u8`
+
+error[E0308]: mismatched types
+ --> $DIR/wrong-type-assume.rs:37:58
+ |
+LL | assert::is_transmutable::<Src, Dst, Context, false, {0u8}, false, false>();
+ | ^^^ expected `bool`, found `u8`
+
+error[E0308]: mismatched types
+ --> $DIR/wrong-type-assume.rs:38:65
+ |
+LL | assert::is_transmutable::<Src, Dst, Context, false, false, {0u8}, false>();
+ | ^^^ expected `bool`, found `u8`
+
+error[E0308]: mismatched types
+ --> $DIR/wrong-type-assume.rs:39:72
+ |
+LL | assert::is_transmutable::<Src, Dst, Context, false, false, false, {0u8}>();
+ | ^^^ expected `bool`, found `u8`
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/transmutability/primitives/bool.rs b/src/test/ui/transmutability/primitives/bool.rs
new file mode 100644
index 000000000..4f79bc253
--- /dev/null
+++ b/src/test/ui/transmutability/primitives/bool.rs
@@ -0,0 +1,25 @@
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code)]
+#![allow(incomplete_features)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
+ {}
+
+ pub fn is_maybe_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, true, true>
+ {}
+}
+
+fn contrast_with_u8() {
+ assert::is_transmutable::<u8, bool>(); //~ ERROR cannot be safely transmuted
+ assert::is_maybe_transmutable::<u8, bool>();
+ assert::is_transmutable::<bool, u8>();
+}
diff --git a/src/test/ui/transmutability/primitives/bool.stderr b/src/test/ui/transmutability/primitives/bool.stderr
new file mode 100644
index 000000000..dc740251c
--- /dev/null
+++ b/src/test/ui/transmutability/primitives/bool.stderr
@@ -0,0 +1,19 @@
+error[E0277]: `u8` cannot be safely transmuted into `bool` in the defining scope of `assert::Context`.
+ --> $DIR/bool.rs:22:35
+ |
+LL | assert::is_transmutable::<u8, bool>();
+ | ^^^^ `u8` cannot be safely transmuted into `bool` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, true>` is not implemented for `bool`
+note: required by a bound in `is_transmutable`
+ --> $DIR/bool.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/transmutability/primitives/numbers.rs b/src/test/ui/transmutability/primitives/numbers.rs
new file mode 100644
index 000000000..a5f79065d
--- /dev/null
+++ b/src/test/ui/transmutability/primitives/numbers.rs
@@ -0,0 +1,128 @@
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code)]
+#![allow(incomplete_features)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+ struct Context;
+
+ pub fn is_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ {}
+}
+
+fn should_accept_identity() {
+ assert::is_transmutable::< i8, i8>();
+ assert::is_transmutable::< u8, u8>();
+ assert::is_transmutable::< i16, i16>();
+ assert::is_transmutable::< u16, u16>();
+ assert::is_transmutable::< i32, i32>();
+ assert::is_transmutable::< f32, f32>();
+ assert::is_transmutable::< u32, u32>();
+ assert::is_transmutable::< i64, i64>();
+ assert::is_transmutable::< f64, f64>();
+ assert::is_transmutable::< u64, u64>();
+ assert::is_transmutable::< i128, i128>();
+ assert::is_transmutable::< u128, u128>();
+ assert::is_transmutable::<isize, isize>();
+ assert::is_transmutable::<usize, usize>();
+}
+
+fn should_be_bitransmutable() {
+ assert::is_transmutable::< i8, u8>();
+ assert::is_transmutable::< u8, i8>();
+
+ assert::is_transmutable::< i16, u16>();
+ assert::is_transmutable::< u16, i16>();
+
+ assert::is_transmutable::< i32, f32>();
+ assert::is_transmutable::< i32, u32>();
+ assert::is_transmutable::< f32, i32>();
+ assert::is_transmutable::< f32, u32>();
+ assert::is_transmutable::< u32, i32>();
+ assert::is_transmutable::< u32, f32>();
+
+ assert::is_transmutable::< u64, i64>();
+ assert::is_transmutable::< u64, f64>();
+ assert::is_transmutable::< i64, u64>();
+ assert::is_transmutable::< i64, f64>();
+ assert::is_transmutable::< f64, u64>();
+ assert::is_transmutable::< f64, i64>();
+
+ assert::is_transmutable::< u128, i128>();
+ assert::is_transmutable::< i128, u128>();
+
+ assert::is_transmutable::<isize, usize>();
+ assert::is_transmutable::<usize, isize>();
+}
+
+fn should_reject_extension() {
+ assert::is_transmutable::< i8, i16>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< i8, u16>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< i8, i32>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< i8, f32>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< i8, u32>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< i8, u64>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< i8, i64>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< i8, f64>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< i8, u128>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< i8, i128>(); //~ ERROR cannot be safely transmuted
+
+ assert::is_transmutable::< u8, i16>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< u8, u16>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< u8, i32>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< u8, f32>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< u8, u32>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< u8, u64>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< u8, i64>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< u8, f64>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< u8, u128>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< u8, i128>(); //~ ERROR cannot be safely transmuted
+
+ assert::is_transmutable::< i16, i32>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< i16, f32>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< i16, u32>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< i16, u64>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< i16, i64>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< i16, f64>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< i16, u128>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< i16, i128>(); //~ ERROR cannot be safely transmuted
+
+ assert::is_transmutable::< u16, i32>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< u16, f32>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< u16, u32>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< u16, u64>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< u16, i64>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< u16, f64>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< u16, u128>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< u16, i128>(); //~ ERROR cannot be safely transmuted
+
+ assert::is_transmutable::< i32, u64>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< i32, i64>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< i32, f64>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< i32, u128>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< i32, i128>(); //~ ERROR cannot be safely transmuted
+
+ assert::is_transmutable::< f32, u64>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< f32, i64>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< f32, f64>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< f32, u128>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< f32, i128>(); //~ ERROR cannot be safely transmuted
+
+ assert::is_transmutable::< u32, u64>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< u32, i64>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< u32, f64>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< u32, u128>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< u32, i128>(); //~ ERROR cannot be safely transmuted
+
+ assert::is_transmutable::< u64, u128>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< u64, i128>(); //~ ERROR cannot be safely transmuted
+
+ assert::is_transmutable::< i64, u128>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< i64, i128>(); //~ ERROR cannot be safely transmuted
+
+ assert::is_transmutable::< f64, u128>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::< f64, i128>(); //~ ERROR cannot be safely transmuted
+}
diff --git a/src/test/ui/transmutability/primitives/numbers.stderr b/src/test/ui/transmutability/primitives/numbers.stderr
new file mode 100644
index 000000000..9b802a444
--- /dev/null
+++ b/src/test/ui/transmutability/primitives/numbers.stderr
@@ -0,0 +1,915 @@
+error[E0277]: `i8` cannot be safely transmuted into `i16` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:62:40
+ |
+LL | assert::is_transmutable::< i8, i16>();
+ | ^^^ `i8` cannot be safely transmuted into `i16` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, false, false, false, false>` is not implemented for `i16`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i8` cannot be safely transmuted into `u16` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:63:40
+ |
+LL | assert::is_transmutable::< i8, u16>();
+ | ^^^ `i8` cannot be safely transmuted into `u16` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, false, false, false, false>` is not implemented for `u16`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i8` cannot be safely transmuted into `i32` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:64:40
+ |
+LL | assert::is_transmutable::< i8, i32>();
+ | ^^^ `i8` cannot be safely transmuted into `i32` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, false, false, false, false>` is not implemented for `i32`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i8` cannot be safely transmuted into `f32` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:65:40
+ |
+LL | assert::is_transmutable::< i8, f32>();
+ | ^^^ `i8` cannot be safely transmuted into `f32` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, false, false, false, false>` is not implemented for `f32`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i8` cannot be safely transmuted into `u32` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:66:40
+ |
+LL | assert::is_transmutable::< i8, u32>();
+ | ^^^ `i8` cannot be safely transmuted into `u32` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, false, false, false, false>` is not implemented for `u32`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i8` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:67:40
+ |
+LL | assert::is_transmutable::< i8, u64>();
+ | ^^^ `i8` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, false, false, false, false>` is not implemented for `u64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i8` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:68:40
+ |
+LL | assert::is_transmutable::< i8, i64>();
+ | ^^^ `i8` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, false, false, false, false>` is not implemented for `i64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i8` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:69:40
+ |
+LL | assert::is_transmutable::< i8, f64>();
+ | ^^^ `i8` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, false, false, false, false>` is not implemented for `f64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i8` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:70:39
+ |
+LL | assert::is_transmutable::< i8, u128>();
+ | ^^^^ `i8` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, false, false, false, false>` is not implemented for `u128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i8` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:71:39
+ |
+LL | assert::is_transmutable::< i8, i128>();
+ | ^^^^ `i8` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, false, false, false, false>` is not implemented for `i128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u8` cannot be safely transmuted into `i16` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:73:40
+ |
+LL | assert::is_transmutable::< u8, i16>();
+ | ^^^ `u8` cannot be safely transmuted into `i16` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, false>` is not implemented for `i16`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u8` cannot be safely transmuted into `u16` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:74:40
+ |
+LL | assert::is_transmutable::< u8, u16>();
+ | ^^^ `u8` cannot be safely transmuted into `u16` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, false>` is not implemented for `u16`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u8` cannot be safely transmuted into `i32` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:75:40
+ |
+LL | assert::is_transmutable::< u8, i32>();
+ | ^^^ `u8` cannot be safely transmuted into `i32` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, false>` is not implemented for `i32`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u8` cannot be safely transmuted into `f32` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:76:40
+ |
+LL | assert::is_transmutable::< u8, f32>();
+ | ^^^ `u8` cannot be safely transmuted into `f32` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, false>` is not implemented for `f32`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u8` cannot be safely transmuted into `u32` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:77:40
+ |
+LL | assert::is_transmutable::< u8, u32>();
+ | ^^^ `u8` cannot be safely transmuted into `u32` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, false>` is not implemented for `u32`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u8` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:78:40
+ |
+LL | assert::is_transmutable::< u8, u64>();
+ | ^^^ `u8` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, false>` is not implemented for `u64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u8` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:79:40
+ |
+LL | assert::is_transmutable::< u8, i64>();
+ | ^^^ `u8` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, false>` is not implemented for `i64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u8` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:80:40
+ |
+LL | assert::is_transmutable::< u8, f64>();
+ | ^^^ `u8` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, false>` is not implemented for `f64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u8` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:81:39
+ |
+LL | assert::is_transmutable::< u8, u128>();
+ | ^^^^ `u8` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, false>` is not implemented for `u128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u8` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:82:39
+ |
+LL | assert::is_transmutable::< u8, i128>();
+ | ^^^^ `u8` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, false, false, false, false>` is not implemented for `i128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i16` cannot be safely transmuted into `i32` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:84:40
+ |
+LL | assert::is_transmutable::< i16, i32>();
+ | ^^^ `i16` cannot be safely transmuted into `i32` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, false, false, false, false>` is not implemented for `i32`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i16` cannot be safely transmuted into `f32` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:85:40
+ |
+LL | assert::is_transmutable::< i16, f32>();
+ | ^^^ `i16` cannot be safely transmuted into `f32` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, false, false, false, false>` is not implemented for `f32`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i16` cannot be safely transmuted into `u32` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:86:40
+ |
+LL | assert::is_transmutable::< i16, u32>();
+ | ^^^ `i16` cannot be safely transmuted into `u32` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, false, false, false, false>` is not implemented for `u32`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i16` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:87:40
+ |
+LL | assert::is_transmutable::< i16, u64>();
+ | ^^^ `i16` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, false, false, false, false>` is not implemented for `u64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i16` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:88:40
+ |
+LL | assert::is_transmutable::< i16, i64>();
+ | ^^^ `i16` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, false, false, false, false>` is not implemented for `i64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i16` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:89:40
+ |
+LL | assert::is_transmutable::< i16, f64>();
+ | ^^^ `i16` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, false, false, false, false>` is not implemented for `f64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i16` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:90:39
+ |
+LL | assert::is_transmutable::< i16, u128>();
+ | ^^^^ `i16` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, false, false, false, false>` is not implemented for `u128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i16` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:91:39
+ |
+LL | assert::is_transmutable::< i16, i128>();
+ | ^^^^ `i16` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, false, false, false, false>` is not implemented for `i128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u16` cannot be safely transmuted into `i32` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:93:40
+ |
+LL | assert::is_transmutable::< u16, i32>();
+ | ^^^ `u16` cannot be safely transmuted into `i32` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, false, false, false, false>` is not implemented for `i32`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u16` cannot be safely transmuted into `f32` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:94:40
+ |
+LL | assert::is_transmutable::< u16, f32>();
+ | ^^^ `u16` cannot be safely transmuted into `f32` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, false, false, false, false>` is not implemented for `f32`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u16` cannot be safely transmuted into `u32` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:95:40
+ |
+LL | assert::is_transmutable::< u16, u32>();
+ | ^^^ `u16` cannot be safely transmuted into `u32` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, false, false, false, false>` is not implemented for `u32`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u16` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:96:40
+ |
+LL | assert::is_transmutable::< u16, u64>();
+ | ^^^ `u16` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, false, false, false, false>` is not implemented for `u64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u16` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:97:40
+ |
+LL | assert::is_transmutable::< u16, i64>();
+ | ^^^ `u16` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, false, false, false, false>` is not implemented for `i64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u16` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:98:40
+ |
+LL | assert::is_transmutable::< u16, f64>();
+ | ^^^ `u16` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, false, false, false, false>` is not implemented for `f64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u16` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:99:39
+ |
+LL | assert::is_transmutable::< u16, u128>();
+ | ^^^^ `u16` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, false, false, false, false>` is not implemented for `u128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u16` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:100:39
+ |
+LL | assert::is_transmutable::< u16, i128>();
+ | ^^^^ `u16` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, false, false, false, false>` is not implemented for `i128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i32` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:102:40
+ |
+LL | assert::is_transmutable::< i32, u64>();
+ | ^^^ `i32` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i32, assert::Context, false, false, false, false>` is not implemented for `u64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i32` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:103:40
+ |
+LL | assert::is_transmutable::< i32, i64>();
+ | ^^^ `i32` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i32, assert::Context, false, false, false, false>` is not implemented for `i64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i32` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:104:40
+ |
+LL | assert::is_transmutable::< i32, f64>();
+ | ^^^ `i32` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i32, assert::Context, false, false, false, false>` is not implemented for `f64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i32` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:105:39
+ |
+LL | assert::is_transmutable::< i32, u128>();
+ | ^^^^ `i32` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i32, assert::Context, false, false, false, false>` is not implemented for `u128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i32` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:106:39
+ |
+LL | assert::is_transmutable::< i32, i128>();
+ | ^^^^ `i32` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i32, assert::Context, false, false, false, false>` is not implemented for `i128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `f32` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:108:40
+ |
+LL | assert::is_transmutable::< f32, u64>();
+ | ^^^ `f32` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<f32, assert::Context, false, false, false, false>` is not implemented for `u64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `f32` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:109:40
+ |
+LL | assert::is_transmutable::< f32, i64>();
+ | ^^^ `f32` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<f32, assert::Context, false, false, false, false>` is not implemented for `i64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `f32` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:110:40
+ |
+LL | assert::is_transmutable::< f32, f64>();
+ | ^^^ `f32` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<f32, assert::Context, false, false, false, false>` is not implemented for `f64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `f32` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:111:39
+ |
+LL | assert::is_transmutable::< f32, u128>();
+ | ^^^^ `f32` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<f32, assert::Context, false, false, false, false>` is not implemented for `u128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `f32` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:112:39
+ |
+LL | assert::is_transmutable::< f32, i128>();
+ | ^^^^ `f32` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<f32, assert::Context, false, false, false, false>` is not implemented for `i128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u32` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:114:40
+ |
+LL | assert::is_transmutable::< u32, u64>();
+ | ^^^ `u32` cannot be safely transmuted into `u64` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u32, assert::Context, false, false, false, false>` is not implemented for `u64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u32` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:115:40
+ |
+LL | assert::is_transmutable::< u32, i64>();
+ | ^^^ `u32` cannot be safely transmuted into `i64` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u32, assert::Context, false, false, false, false>` is not implemented for `i64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u32` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:116:40
+ |
+LL | assert::is_transmutable::< u32, f64>();
+ | ^^^ `u32` cannot be safely transmuted into `f64` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u32, assert::Context, false, false, false, false>` is not implemented for `f64`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u32` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:117:39
+ |
+LL | assert::is_transmutable::< u32, u128>();
+ | ^^^^ `u32` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u32, assert::Context, false, false, false, false>` is not implemented for `u128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u32` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:118:39
+ |
+LL | assert::is_transmutable::< u32, i128>();
+ | ^^^^ `u32` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u32, assert::Context, false, false, false, false>` is not implemented for `i128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u64` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:120:39
+ |
+LL | assert::is_transmutable::< u64, u128>();
+ | ^^^^ `u64` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u64, assert::Context, false, false, false, false>` is not implemented for `u128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `u64` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:121:39
+ |
+LL | assert::is_transmutable::< u64, i128>();
+ | ^^^^ `u64` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u64, assert::Context, false, false, false, false>` is not implemented for `i128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i64` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:123:39
+ |
+LL | assert::is_transmutable::< i64, u128>();
+ | ^^^^ `i64` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i64, assert::Context, false, false, false, false>` is not implemented for `u128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `i64` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:124:39
+ |
+LL | assert::is_transmutable::< i64, i128>();
+ | ^^^^ `i64` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<i64, assert::Context, false, false, false, false>` is not implemented for `i128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `f64` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:126:39
+ |
+LL | assert::is_transmutable::< f64, u128>();
+ | ^^^^ `f64` cannot be safely transmuted into `u128` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<f64, assert::Context, false, false, false, false>` is not implemented for `u128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `f64` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
+ --> $DIR/numbers.rs:127:39
+ |
+LL | assert::is_transmutable::< f64, i128>();
+ | ^^^^ `f64` cannot be safely transmuted into `i128` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<f64, assert::Context, false, false, false, false>` is not implemented for `i128`
+note: required by a bound in `is_transmutable`
+ --> $DIR/numbers.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error: aborting due to 57 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/transmutability/primitives/unit.rs b/src/test/ui/transmutability/primitives/unit.rs
new file mode 100644
index 000000000..86d474030
--- /dev/null
+++ b/src/test/ui/transmutability/primitives/unit.rs
@@ -0,0 +1,24 @@
+//! The unit type, `()`, should be one byte.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+
+ pub fn is_transmutable<Src, Dst, Context>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ {}
+}
+
+#[repr(C)]
+struct Zst;
+
+fn should_have_correct_size() {
+ struct Context;
+ assert::is_transmutable::<(), Zst, Context>();
+ assert::is_transmutable::<Zst, (), Context>();
+ assert::is_transmutable::<(), u8, Context>(); //~ ERROR cannot be safely transmuted
+}
diff --git a/src/test/ui/transmutability/primitives/unit.stderr b/src/test/ui/transmutability/primitives/unit.stderr
new file mode 100644
index 000000000..cf27c0d17
--- /dev/null
+++ b/src/test/ui/transmutability/primitives/unit.stderr
@@ -0,0 +1,19 @@
+error[E0277]: `()` cannot be safely transmuted into `u8` in the defining scope of `should_have_correct_size::Context`.
+ --> $DIR/unit.rs:23:35
+ |
+LL | assert::is_transmutable::<(), u8, Context>();
+ | ^^ `()` cannot be safely transmuted into `u8` in the defining scope of `should_have_correct_size::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<(), should_have_correct_size::Context, true, true, true, true>` is not implemented for `u8`
+note: required by a bound in `is_transmutable`
+ --> $DIR/unit.rs:12:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/transmutability/references.rs b/src/test/ui/transmutability/references.rs
new file mode 100644
index 000000000..c6fd4c43e
--- /dev/null
+++ b/src/test/ui/transmutability/references.rs
@@ -0,0 +1,20 @@
+//! Transmutations involving references are not yet supported.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code, incomplete_features, non_camel_case_types)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_maybe_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ {}
+}
+
+fn not_yet_implemented() {
+ #[repr(C)] struct Unit;
+ assert::is_maybe_transmutable::<&'static Unit, &'static Unit>(); //~ ERROR cannot be safely transmuted
+}
diff --git a/src/test/ui/transmutability/references.stderr b/src/test/ui/transmutability/references.stderr
new file mode 100644
index 000000000..b1359ea58
--- /dev/null
+++ b/src/test/ui/transmutability/references.stderr
@@ -0,0 +1,19 @@
+error[E0277]: `&'static Unit` cannot be safely transmuted into `&'static Unit` in the defining scope of `assert::Context`.
+ --> $DIR/references.rs:19:37
+ |
+LL | assert::is_maybe_transmutable::<&'static Unit, &'static Unit>();
+ | ^^^^^^^^^^^^^ `&'static Unit` cannot be safely transmuted into `&'static Unit` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<&'static Unit, assert::Context, true, true, true, true>` is not implemented for `&'static Unit`
+note: required by a bound in `is_maybe_transmutable`
+ --> $DIR/references.rs:13:14
+ |
+LL | pub fn is_maybe_transmutable<Src, Dst>()
+ | --------------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/transmutability/structs/repr/should_handle_align.rs b/src/test/ui/transmutability/structs/repr/should_handle_align.rs
new file mode 100644
index 000000000..71720165a
--- /dev/null
+++ b/src/test/ui/transmutability/structs/repr/should_handle_align.rs
@@ -0,0 +1,36 @@
+// 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::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_maybe_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ {}
+}
+
+fn should_pad_explicitly_aligned_field() {
+ #[derive(Clone, Copy)] #[repr(u8)] enum V0u8 { V = 0 }
+
+ #[repr(C)]
+ pub union Uninit {
+ a: (),
+ b: V0u8,
+ }
+
+ #[repr(C, align(2))] struct align_2(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/src/test/ui/transmutability/structs/repr/should_handle_packed.rs b/src/test/ui/transmutability/structs/repr/should_handle_packed.rs
new file mode 100644
index 000000000..ae8acf504
--- /dev/null
+++ b/src/test/ui/transmutability/structs/repr/should_handle_packed.rs
@@ -0,0 +1,35 @@
+// 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::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_maybe_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ {}
+}
+
+fn should_pad_explicitly_packed_field() {
+ #[derive(Clone, Copy)] #[repr(u8)] enum V0u8 { V = 0 }
+ #[derive(Clone, Copy)] #[repr(u32)] enum V0u32 { V = 0 }
+
+ #[repr(C)]
+ pub union Uninit {
+ a: (),
+ b: V0u8,
+ }
+
+ #[repr(C, packed(2))] struct ImplicitlyPadded(V0u8, V0u32);
+ #[repr(C)] struct ExplicitlyPadded(V0u8, Uninit, V0u8, V0u8, V0u8, 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/src/test/ui/transmutability/structs/repr/should_require_well_defined_layout.rs b/src/test/ui/transmutability/structs/repr/should_require_well_defined_layout.rs
new file mode 100644
index 000000000..556be989d
--- /dev/null
+++ b/src/test/ui/transmutability/structs/repr/should_require_well_defined_layout.rs
@@ -0,0 +1,76 @@
+//! 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::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_maybe_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ {}
+}
+
+fn should_reject_repr_rust()
+{
+ fn unit() {
+ struct repr_rust;
+ assert::is_maybe_transmutable::<repr_rust, ()>(); //~ ERROR cannot be safely transmuted
+ assert::is_maybe_transmutable::<u128, repr_rust>(); //~ ERROR cannot be safely transmuted
+ }
+
+ fn tuple() {
+ struct repr_rust();
+ assert::is_maybe_transmutable::<repr_rust, ()>(); //~ ERROR cannot be safely transmuted
+ assert::is_maybe_transmutable::<u128, repr_rust>(); //~ ERROR cannot be safely transmuted
+ }
+
+ fn braces() {
+ struct repr_rust{}
+ assert::is_maybe_transmutable::<repr_rust, ()>(); //~ ERROR cannot be safely transmuted
+ assert::is_maybe_transmutable::<u128, repr_rust>(); //~ ERROR cannot be safely transmuted
+ }
+
+ fn aligned() {
+ #[repr(align(1))] struct repr_rust{}
+ assert::is_maybe_transmutable::<repr_rust, ()>(); //~ ERROR cannot be safely transmuted
+ assert::is_maybe_transmutable::<u128, repr_rust>(); //~ ERROR cannot be safely transmuted
+ }
+
+ fn packed() {
+ #[repr(packed)] struct repr_rust{}
+ assert::is_maybe_transmutable::<repr_rust, ()>(); //~ ERROR cannot be safely transmuted
+ assert::is_maybe_transmutable::<u128, repr_rust>(); //~ ERROR cannot be safely transmuted
+ }
+
+ fn nested() {
+ struct repr_rust;
+ #[repr(C)] struct repr_c(repr_rust);
+ assert::is_maybe_transmutable::<repr_c, ()>(); //~ ERROR cannot be safely transmuted
+ assert::is_maybe_transmutable::<u128, repr_c>(); //~ ERROR cannot be safely transmuted
+ }
+}
+
+fn should_accept_repr_C()
+{
+ fn unit() {
+ #[repr(C)] struct repr_c;
+ assert::is_maybe_transmutable::<repr_c, ()>();
+ assert::is_maybe_transmutable::<i128, repr_c>();
+ }
+
+ fn tuple() {
+ #[repr(C)] struct repr_c();
+ assert::is_maybe_transmutable::<repr_c, ()>();
+ assert::is_maybe_transmutable::<i128, repr_c>();
+ }
+
+ fn braces() {
+ #[repr(C)] struct repr_c{}
+ assert::is_maybe_transmutable::<repr_c, ()>();
+ assert::is_maybe_transmutable::<i128, repr_c>();
+ }
+}
diff --git a/src/test/ui/transmutability/structs/repr/should_require_well_defined_layout.stderr b/src/test/ui/transmutability/structs/repr/should_require_well_defined_layout.stderr
new file mode 100644
index 000000000..07355f7c2
--- /dev/null
+++ b/src/test/ui/transmutability/structs/repr/should_require_well_defined_layout.stderr
@@ -0,0 +1,195 @@
+error[E0277]: `should_reject_repr_rust::unit::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:21:52
+ |
+LL | assert::is_maybe_transmutable::<repr_rust, ()>();
+ | ^^ `should_reject_repr_rust::unit::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<should_reject_repr_rust::unit::repr_rust, assert::Context, true, true, true, 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, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `u128` cannot be safely transmuted into `should_reject_repr_rust::unit::repr_rust` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:22:47
+ |
+LL | assert::is_maybe_transmutable::<u128, repr_rust>();
+ | ^^^^^^^^^ `u128` cannot be safely transmuted into `should_reject_repr_rust::unit::repr_rust` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `should_reject_repr_rust::unit::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, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `should_reject_repr_rust::tuple::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:27:52
+ |
+LL | assert::is_maybe_transmutable::<repr_rust, ()>();
+ | ^^ `should_reject_repr_rust::tuple::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<should_reject_repr_rust::tuple::repr_rust, assert::Context, true, true, true, 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, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `u128` cannot be safely transmuted into `should_reject_repr_rust::tuple::repr_rust` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:28:47
+ |
+LL | assert::is_maybe_transmutable::<u128, repr_rust>();
+ | ^^^^^^^^^ `u128` cannot be safely transmuted into `should_reject_repr_rust::tuple::repr_rust` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `should_reject_repr_rust::tuple::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, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `should_reject_repr_rust::braces::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:33:52
+ |
+LL | assert::is_maybe_transmutable::<repr_rust, ()>();
+ | ^^ `should_reject_repr_rust::braces::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<should_reject_repr_rust::braces::repr_rust, assert::Context, true, true, true, 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, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `u128` cannot be safely transmuted into `should_reject_repr_rust::braces::repr_rust` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:34:47
+ |
+LL | assert::is_maybe_transmutable::<u128, repr_rust>();
+ | ^^^^^^^^^ `u128` cannot be safely transmuted into `should_reject_repr_rust::braces::repr_rust` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `should_reject_repr_rust::braces::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, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `aligned::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:39:52
+ |
+LL | assert::is_maybe_transmutable::<repr_rust, ()>();
+ | ^^ `aligned::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<aligned::repr_rust, assert::Context, true, true, true, 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, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `u128` cannot be safely transmuted into `aligned::repr_rust` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:40:47
+ |
+LL | assert::is_maybe_transmutable::<u128, repr_rust>();
+ | ^^^^^^^^^ `u128` cannot be safely transmuted into `aligned::repr_rust` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `aligned::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, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `packed::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:45:52
+ |
+LL | assert::is_maybe_transmutable::<repr_rust, ()>();
+ | ^^ `packed::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<packed::repr_rust, assert::Context, true, true, true, 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, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `u128` cannot be safely transmuted into `packed::repr_rust` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:46:47
+ |
+LL | assert::is_maybe_transmutable::<u128, repr_rust>();
+ | ^^^^^^^^^ `u128` cannot be safely transmuted into `packed::repr_rust` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `packed::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, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `nested::repr_c` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:52:49
+ |
+LL | assert::is_maybe_transmutable::<repr_c, ()>();
+ | ^^ `nested::repr_c` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<nested::repr_c, assert::Context, true, true, true, 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, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `u128` cannot be safely transmuted into `nested::repr_c` in the defining scope of `assert::Context`.
+ --> $DIR/should_require_well_defined_layout.rs:53:47
+ |
+LL | assert::is_maybe_transmutable::<u128, repr_c>();
+ | ^^^^^^ `u128` cannot be safely transmuted into `nested::repr_c` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `nested::repr_c`
+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, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error: aborting due to 12 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/transmutability/structs/should_order_fields_correctly.rs b/src/test/ui/transmutability/structs/should_order_fields_correctly.rs
new file mode 100644
index 000000000..db49b914f
--- /dev/null
+++ b/src/test/ui/transmutability/structs/should_order_fields_correctly.rs
@@ -0,0 +1,31 @@
+// check-pass
+//! The fields of a struct should be laid out in lexical order.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ {}
+}
+
+#[repr(u8)] enum V0 { V = 0 }
+#[repr(u8)] enum V1 { V = 1 }
+#[repr(u8)] enum V2 { V = 2 }
+
+#[repr(C)] struct S01(V0, V1);
+#[repr(C)] struct S012(V0, V1, V2);
+
+fn should_order_tag_and_fields_correctly() {
+ // An implementation that (incorrectly) arranges S01 as [0x01, 0x00] will,
+ // in principle, reject this transmutation.
+ assert::is_transmutable::<S01, V0>();
+ // Again, but with one more field.
+ assert::is_transmutable::<S012, S01>();
+}
diff --git a/src/test/ui/transmutability/unions/boolish.rs b/src/test/ui/transmutability/unions/boolish.rs
new file mode 100644
index 000000000..975118b99
--- /dev/null
+++ b/src/test/ui/transmutability/unions/boolish.rs
@@ -0,0 +1,31 @@
+// check-pass
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![feature(marker_trait_attr)]
+#![allow(dead_code)]
+#![allow(incomplete_features)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
+ {}
+}
+
+fn should_match_bool() {
+ #[derive(Copy, Clone)] #[repr(u8)] pub enum False { V = 0 }
+ #[derive(Copy, Clone)] #[repr(u8)] pub enum True { V = 1 }
+
+ #[repr(C)]
+ pub union Bool {
+ pub f: False,
+ pub t: True,
+ }
+
+ assert::is_transmutable::<Bool, bool>();
+ assert::is_transmutable::<bool, Bool>();
+}
diff --git a/src/test/ui/transmutability/unions/repr/should_handle_align.rs b/src/test/ui/transmutability/unions/repr/should_handle_align.rs
new file mode 100644
index 000000000..e215799a2
--- /dev/null
+++ b/src/test/ui/transmutability/unions/repr/should_handle_align.rs
@@ -0,0 +1,40 @@
+// 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::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_maybe_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, 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/src/test/ui/transmutability/unions/repr/should_handle_packed.rs b/src/test/ui/transmutability/unions/repr/should_handle_packed.rs
new file mode 100644
index 000000000..34a53c7a8
--- /dev/null
+++ b/src/test/ui/transmutability/unions/repr/should_handle_packed.rs
@@ -0,0 +1,41 @@
+// 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::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_maybe_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, 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/src/test/ui/transmutability/unions/repr/should_require_well_defined_layout.rs b/src/test/ui/transmutability/unions/repr/should_require_well_defined_layout.rs
new file mode 100644
index 000000000..cec8e389f
--- /dev/null
+++ b/src/test/ui/transmutability/unions/repr/should_require_well_defined_layout.rs
@@ -0,0 +1,37 @@
+//! 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::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_maybe_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, 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/src/test/ui/transmutability/unions/repr/should_require_well_defined_layout.stderr b/src/test/ui/transmutability/unions/repr/should_require_well_defined_layout.stderr
new file mode 100644
index 000000000..2ed01b159
--- /dev/null
+++ b/src/test/ui/transmutability/unions/repr/should_require_well_defined_layout.stderr
@@ -0,0 +1,35 @@
+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:23:48
+ |
+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, true, true, true, 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, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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:24:43
+ |
+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, true, true, true, 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, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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`.
diff --git a/src/test/ui/transmutability/unions/should_pad_variants.rs b/src/test/ui/transmutability/unions/should_pad_variants.rs
new file mode 100644
index 000000000..c4757900f
--- /dev/null
+++ b/src/test/ui/transmutability/unions/should_pad_variants.rs
@@ -0,0 +1,40 @@
+//! The variants of a union must be padded with uninit bytes such that they have
+//! the same length (in bytes).
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+
+ pub fn is_transmutable<Src, Dst, Context>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ {}
+}
+
+#[derive(Clone, Copy)]
+#[repr(C)] struct Zst;
+
+#[derive(Clone, Copy)]
+#[repr(u8)] enum V0 { V = 0 }
+
+#[derive(Clone, Copy)]
+#[repr(u8)] enum V2 { V = 2 }
+
+#[repr(C)]
+union Lopsided {
+ smol: Zst,
+ lorg: V0,
+}
+
+#[repr(C)] struct Src(V0, Zst, V2);
+#[repr(C)] struct Dst(V0, Lopsided, V2);
+
+fn should_pad_variants() {
+ struct Context;
+ // If the implementation (incorrectly) fails to pad `Lopsided::smol` with
+ // an uninitialized byte, this transmutation might be (wrongly) accepted:
+ assert::is_transmutable::<Src, Dst, Context>(); //~ ERROR cannot be safely transmuted
+}
diff --git a/src/test/ui/transmutability/unions/should_pad_variants.stderr b/src/test/ui/transmutability/unions/should_pad_variants.stderr
new file mode 100644
index 000000000..429f7211d
--- /dev/null
+++ b/src/test/ui/transmutability/unions/should_pad_variants.stderr
@@ -0,0 +1,19 @@
+error[E0277]: `Src` cannot be safely transmuted into `Dst` in the defining scope of `should_pad_variants::Context`.
+ --> $DIR/should_pad_variants.rs:39:36
+ |
+LL | assert::is_transmutable::<Src, Dst, Context>();
+ | ^^^ `Src` cannot be safely transmuted into `Dst` in the defining scope of `should_pad_variants::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<Src, should_pad_variants::Context, true, true, true, true>` is not implemented for `Dst`
+note: required by a bound in `is_transmutable`
+ --> $DIR/should_pad_variants.rs:13:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/transmutability/unions/should_permit_intersecting_if_validity_is_assumed.rs b/src/test/ui/transmutability/unions/should_permit_intersecting_if_validity_is_assumed.rs
new file mode 100644
index 000000000..2493d7155
--- /dev/null
+++ b/src/test/ui/transmutability/unions/should_permit_intersecting_if_validity_is_assumed.rs
@@ -0,0 +1,39 @@
+// check-pass
+//! If validity is assumed, there need only be one matching bit-pattern between
+//! the source and destination types.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code, incomplete_features, non_camel_case_types)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_maybe_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, true, true>
+ // validity IS assumed --------------------------------^^^^
+ {}
+}
+
+#[derive(Clone, Copy)] #[repr(u8)] enum Ox00 { V = 0x00 }
+#[derive(Clone, Copy)] #[repr(u8)] enum Ox7F { V = 0x7F }
+#[derive(Clone, Copy)] #[repr(u8)] enum OxFF { V = 0xFF }
+
+fn test() {
+ #[repr(C)]
+ union A {
+ a: Ox00,
+ b: Ox7F,
+ }
+
+ #[repr(C)]
+ union B {
+ a: Ox7F,
+ b: OxFF,
+ }
+
+ assert::is_maybe_transmutable::<A, B>();
+ assert::is_maybe_transmutable::<B, A>();
+}
diff --git a/src/test/ui/transmutability/unions/should_reject_contraction.rs b/src/test/ui/transmutability/unions/should_reject_contraction.rs
new file mode 100644
index 000000000..e8138d0e0
--- /dev/null
+++ b/src/test/ui/transmutability/unions/should_reject_contraction.rs
@@ -0,0 +1,36 @@
+//! Validity may not be contracted, unless validity is assumed.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code, incomplete_features, non_camel_case_types)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
+ {}
+}
+
+#[derive(Clone, Copy)] #[repr(u8)] enum Ox00 { V = 0x00 }
+#[derive(Clone, Copy)] #[repr(u8)] enum Ox01 { V = 0x01 }
+#[derive(Clone, Copy)] #[repr(u8)] enum OxFF { V = 0xFF }
+
+fn test() {
+ #[repr(C)]
+ union Subset {
+ a: Ox00,
+ b: OxFF,
+ }
+
+ #[repr(C)]
+ union Superset {
+ a: Ox00,
+ b: OxFF,
+ c: Ox01,
+ }
+
+ assert::is_transmutable::<Superset, Subset>(); //~ ERROR cannot be safely transmuted
+}
diff --git a/src/test/ui/transmutability/unions/should_reject_contraction.stderr b/src/test/ui/transmutability/unions/should_reject_contraction.stderr
new file mode 100644
index 000000000..99f589008
--- /dev/null
+++ b/src/test/ui/transmutability/unions/should_reject_contraction.stderr
@@ -0,0 +1,19 @@
+error[E0277]: `Superset` cannot be safely transmuted into `Subset` in the defining scope of `assert::Context`.
+ --> $DIR/should_reject_contraction.rs:35:41
+ |
+LL | assert::is_transmutable::<Superset, Subset>();
+ | ^^^^^^ `Superset` cannot be safely transmuted into `Subset` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<Superset, assert::Context, false, false, false, true>` is not implemented for `Subset`
+note: required by a bound in `is_transmutable`
+ --> $DIR/should_reject_contraction.rs:13:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/transmutability/unions/should_reject_disjoint.rs b/src/test/ui/transmutability/unions/should_reject_disjoint.rs
new file mode 100644
index 000000000..16160e29a
--- /dev/null
+++ b/src/test/ui/transmutability/unions/should_reject_disjoint.rs
@@ -0,0 +1,36 @@
+//! Validity must be satisfiable, even if validity is assumed.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code, incomplete_features, non_camel_case_types)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_maybe_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, true, true>
+ // validity IS assumed --------------------------------^^^^
+ {}
+}
+
+#[derive(Clone, Copy)] #[repr(u8)] enum Ox00 { V = 0x00 }
+#[derive(Clone, Copy)] #[repr(u8)] enum Ox01 { V = 0x01 }
+#[derive(Clone, Copy)] #[repr(u8)] enum OxFF { V = 0xFF }
+
+fn test() {
+ #[repr(C)]
+ union A {
+ a: Ox00,
+ b: OxFF,
+ }
+
+ #[repr(C)]
+ union B {
+ c: Ox01,
+ }
+
+ assert::is_maybe_transmutable::<A, B>(); //~ ERROR cannot be safely transmuted
+ assert::is_maybe_transmutable::<B, A>(); //~ ERROR cannot be safely transmuted
+}
diff --git a/src/test/ui/transmutability/unions/should_reject_disjoint.stderr b/src/test/ui/transmutability/unions/should_reject_disjoint.stderr
new file mode 100644
index 000000000..5714e2bf3
--- /dev/null
+++ b/src/test/ui/transmutability/unions/should_reject_disjoint.stderr
@@ -0,0 +1,35 @@
+error[E0277]: `A` cannot be safely transmuted into `B` in the defining scope of `assert::Context`.
+ --> $DIR/should_reject_disjoint.rs:34:40
+ |
+LL | assert::is_maybe_transmutable::<A, B>();
+ | ^ `A` cannot be safely transmuted into `B` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<A, assert::Context, false, false, true, true>` is not implemented for `B`
+note: required by a bound in `is_maybe_transmutable`
+ --> $DIR/should_reject_disjoint.rs:13:14
+ |
+LL | pub fn is_maybe_transmutable<Src, Dst>()
+ | --------------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+
+error[E0277]: `B` cannot be safely transmuted into `A` in the defining scope of `assert::Context`.
+ --> $DIR/should_reject_disjoint.rs:35:40
+ |
+LL | assert::is_maybe_transmutable::<B, A>();
+ | ^ `B` cannot be safely transmuted into `A` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<B, assert::Context, false, false, true, true>` is not implemented for `A`
+note: required by a bound in `is_maybe_transmutable`
+ --> $DIR/should_reject_disjoint.rs:13:14
+ |
+LL | pub fn is_maybe_transmutable<Src, Dst>()
+ | --------------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, true, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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`.
diff --git a/src/test/ui/transmutability/unions/should_reject_intersecting.rs b/src/test/ui/transmutability/unions/should_reject_intersecting.rs
new file mode 100644
index 000000000..58e399fb9
--- /dev/null
+++ b/src/test/ui/transmutability/unions/should_reject_intersecting.rs
@@ -0,0 +1,38 @@
+//! ALL valid bit patterns of the source must be valid bit patterns of the
+//! destination type, unless validity is assumed.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code, incomplete_features, non_camel_case_types)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+ pub struct Context;
+
+ pub fn is_transmutable<Src, Dst>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
+ // validity is NOT assumed ----------------------------^^^^^
+ {}
+}
+
+#[derive(Clone, Copy)] #[repr(u8)] enum Ox00 { V = 0x00 }
+#[derive(Clone, Copy)] #[repr(u8)] enum Ox7F { V = 0x7F }
+#[derive(Clone, Copy)] #[repr(u8)] enum OxFF { V = 0xFF }
+
+fn test() {
+ #[repr(C)]
+ union A {
+ a: Ox00,
+ b: Ox7F,
+ }
+
+ #[repr(C)]
+ union B {
+ a: Ox7F,
+ b: OxFF,
+ }
+
+ assert::is_transmutable::<A, B>(); //~ ERROR cannot be safely transmuted
+ assert::is_transmutable::<B, A>(); //~ ERROR cannot be safely transmuted
+}
diff --git a/src/test/ui/transmutability/unions/should_reject_intersecting.stderr b/src/test/ui/transmutability/unions/should_reject_intersecting.stderr
new file mode 100644
index 000000000..92689a5f8
--- /dev/null
+++ b/src/test/ui/transmutability/unions/should_reject_intersecting.stderr
@@ -0,0 +1,35 @@
+error[E0277]: `A` cannot be safely transmuted into `B` in the defining scope of `assert::Context`.
+ --> $DIR/should_reject_intersecting.rs:36:34
+ |
+LL | assert::is_transmutable::<A, B>();
+ | ^ `A` cannot be safely transmuted into `B` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<A, assert::Context, false, false, false, true>` is not implemented for `B`
+note: required by a bound in `is_transmutable`
+ --> $DIR/should_reject_intersecting.rs:14:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error[E0277]: `B` cannot be safely transmuted into `A` in the defining scope of `assert::Context`.
+ --> $DIR/should_reject_intersecting.rs:37:34
+ |
+LL | assert::is_transmutable::<B, A>();
+ | ^ `B` cannot be safely transmuted into `A` in the defining scope of `assert::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<B, assert::Context, false, false, false, true>` is not implemented for `A`
+note: required by a bound in `is_transmutable`
+ --> $DIR/should_reject_intersecting.rs:14:14
+ |
+LL | pub fn is_transmutable<Src, Dst>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_private_field.rs b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_private_field.rs
new file mode 100644
index 000000000..5a8c81049
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_private_field.rs
@@ -0,0 +1,38 @@
+// check-pass
+//! If visibility is assumed, a transmutation should be accepted even if the
+//! destination type contains a private field.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+
+ pub fn is_transmutable<Src, Dst, Context>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
+ // visibility IS assumed -------------------------------------^^^^
+ {}
+}
+
+mod src {
+ #[repr(C)] pub(self) struct Zst;
+
+ #[repr(C)] pub(in super) struct Src {
+ pub(self) field: Zst,
+ }
+}
+
+mod dst {
+ #[repr(C)] pub(in super) struct Zst;
+
+ #[repr(C)] pub(in super) struct Dst {
+ pub(self) field: Zst, // <- private field
+ }
+}
+
+fn test() {
+ struct Context;
+ assert::is_transmutable::<src::Src, dst::Dst, Context>();
+}
diff --git a/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_private_variant.rs b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_private_variant.rs
new file mode 100644
index 000000000..77ab4fa6b
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_private_variant.rs
@@ -0,0 +1,39 @@
+// check-pass
+//! If visibility is assumed, a transmutation should be accepted even if the
+//! destination type contains a private variant.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+
+ pub fn is_transmutable<Src, Dst, Context>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
+ // visibility IS assumed -------------------------------------^^^^
+ {}
+}
+
+mod src {
+ #[repr(C)] pub(self) struct Zst;
+
+ #[repr(C)] pub(in super) struct Src {
+ pub(self) field: Zst,
+ }
+}
+
+mod dst {
+ #[derive(Copy, Clone)]
+ #[repr(C)] pub(in super) struct Zst;
+
+ #[repr(C)] pub(in super) union Dst {
+ pub(self) field: Zst, // <- private variant
+ }
+}
+
+fn test() {
+ struct Context;
+ assert::is_transmutable::<src::Src, dst::Dst, Context>();
+}
diff --git a/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_tricky_unreachable_field.rs b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_tricky_unreachable_field.rs
new file mode 100644
index 000000000..2421b24cb
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_tricky_unreachable_field.rs
@@ -0,0 +1,46 @@
+// check-pass
+//! Unless visibility is assumed, a transmutation should be rejected if the
+//! destination type contains an unreachable field (e.g., a public field with a
+//! private type). (This rule is distinct from type privacy, which still may
+//! forbid naming such types.)
+//!
+//! This test exercises a tricky-to-implement instance of this principle: the
+//! "pub-in-priv trick". In the below example, the type `dst::private::Zst` is
+//! unreachable from `Context`.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+
+ pub fn is_transmutable<Src, Dst, Context>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
+ // visibility IS assumed -------------------------------------^^^^
+ {}
+}
+
+mod src {
+ #[repr(C)] pub(in super) struct Zst;
+
+ #[repr(C)] pub(in super) struct Src {
+ pub(in super) field: Zst,
+ }
+}
+
+mod dst {
+ mod private {
+ #[repr(C)] pub struct Zst; // <- unreachable type
+ }
+
+ #[repr(C)] pub(in super) struct Dst {
+ pub(in super) field: private::Zst,
+ }
+}
+
+fn test() {
+ struct Context;
+ assert::is_transmutable::<src::Src, dst::Dst, Context>();
+}
diff --git a/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_field.rs b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_field.rs
new file mode 100644
index 000000000..80b454fda
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_field.rs
@@ -0,0 +1,39 @@
+//! If visibility is assumed, a transmutation should be accepted even if the
+//! destination type contains an unreachable field (e.g., a public field with a
+//! private type). (This rule is distinct from type privacy, which still may
+//! forbid naming such types.)
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+
+ pub fn is_transmutable<Src, Dst, Context>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
+ // visibility IS assumed -------------------------------------^^^^
+ {}
+}
+
+mod src {
+ #[repr(C)] pub(self) struct Zst;
+
+ #[repr(C)] pub(in super) struct Src {
+ pub(self) field: Zst,
+ }
+}
+
+mod dst {
+ #[repr(C)] pub(self) struct Zst; // <- unreachable type
+
+ #[repr(C)] pub(in super) struct Dst {
+ pub(in super) field: Zst, //~ ERROR private type
+ }
+}
+
+fn test() {
+ struct Context;
+ assert::is_transmutable::<src::Src, dst::Dst, Context>();
+}
diff --git a/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_field.stderr b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_field.stderr
new file mode 100644
index 000000000..be83b7ce3
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_field.stderr
@@ -0,0 +1,12 @@
+error[E0446]: private type `dst::Zst` in public interface
+ --> $DIR/should_accept_if_dst_has_unreachable_field.rs:32:9
+ |
+LL | #[repr(C)] pub(self) struct Zst; // <- unreachable type
+ | -------------------- `dst::Zst` declared as private
+...
+LL | pub(in super) field: Zst,
+ | ^^^^^^^^^^^^^^^^^^^^^^^^ can't leak private type
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0446`.
diff --git a/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_ty.rs b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_ty.rs
new file mode 100644
index 000000000..7c53c91e4
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_ty.rs
@@ -0,0 +1,40 @@
+//! If visibility is assumed, a transmutation should be accepted even if the
+//! destination type contains an unreachable field (e.g., a public field with a
+//! private type). (This rule is distinct from type privacy, which still may
+//! forbid naming such types.)
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+
+ pub fn is_transmutable<Src, Dst, Context>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
+ // visibility IS assumed -------------------------------------^^^^
+ {}
+}
+
+mod src {
+ #[repr(C)] pub(self) struct Zst;
+
+ #[repr(C)] pub(in super) struct Src {
+ pub(self) field: Zst,
+ }
+}
+
+mod dst {
+ #[repr(C)] pub(in super) struct Zst;
+
+ // unreachable type
+ #[repr(C)] pub(self) struct Dst {
+ pub(in super) field: Zst,
+ }
+}
+
+fn test() {
+ struct Context;
+ assert::is_transmutable::<src::Src, dst::Dst, Context>(); //~ ERROR `Dst` is private
+}
diff --git a/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_ty.stderr b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_ty.stderr
new file mode 100644
index 000000000..827df05de
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/assume/should_accept_if_dst_has_unreachable_ty.stderr
@@ -0,0 +1,15 @@
+error[E0603]: struct `Dst` is private
+ --> $DIR/should_accept_if_dst_has_unreachable_ty.rs:39:46
+ |
+LL | assert::is_transmutable::<src::Src, dst::Dst, Context>();
+ | ^^^ private struct
+ |
+note: the struct `Dst` is defined here
+ --> $DIR/should_accept_if_dst_has_unreachable_ty.rs:32:16
+ |
+LL | #[repr(C)] pub(self) struct Dst {
+ | ^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0603`.
diff --git a/src/test/ui/transmutability/visibility/should_accept_if_src_has_private_field.rs b/src/test/ui/transmutability/visibility/should_accept_if_src_has_private_field.rs
new file mode 100644
index 000000000..c3f298f01
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/should_accept_if_src_has_private_field.rs
@@ -0,0 +1,38 @@
+// check-pass
+//! The presence of a private field in the source type does not affect
+//! transmutability.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+
+ pub fn is_transmutable<Src, Dst, Context>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ // visibility is NOT assumed ---------------------------------^^^^^
+ {}
+}
+
+mod src {
+ #[repr(C)] pub(in super) struct Zst;
+
+ #[repr(C)] pub(in super) struct Src {
+ pub(self) field: Zst, // <- private field
+ }
+}
+
+mod dst {
+ #[repr(C)] pub(in super) struct Zst;
+
+ #[repr(C)] pub(in super) struct Dst {
+ pub(in super) field: Zst,
+ }
+}
+
+fn test() {
+ struct Context;
+ assert::is_transmutable::<src::Src, dst::Dst, Context>();
+}
diff --git a/src/test/ui/transmutability/visibility/should_accept_if_src_has_private_variant.rs b/src/test/ui/transmutability/visibility/should_accept_if_src_has_private_variant.rs
new file mode 100644
index 000000000..73f6aece5
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/should_accept_if_src_has_private_variant.rs
@@ -0,0 +1,39 @@
+// check-pass
+//! The presence of a private variant in the source type does not affect
+//! transmutability.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+
+ pub fn is_transmutable<Src, Dst, Context>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ // visibility is NOT assumed ---------------------------------^^^^^
+ {}
+}
+
+mod src {
+ #[derive(Copy, Clone)]
+ #[repr(C)] pub(in super) struct Zst;
+
+ #[repr(C)] pub(in super) union Src {
+ pub(self) field: Zst, // <- private variant
+ }
+}
+
+mod dst {
+ #[repr(C)] pub(in super) struct Zst;
+
+ #[repr(C)] pub(in super) struct Dst {
+ pub(in super) field: Zst,
+ }
+}
+
+fn test() {
+ struct Context;
+ assert::is_transmutable::<src::Src, dst::Dst, Context>();
+}
diff --git a/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_field.rs b/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_field.rs
new file mode 100644
index 000000000..6d602601e
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_field.rs
@@ -0,0 +1,38 @@
+//! The presence of an unreachable field in the source type (e.g., a public
+//! field with a private type does not affect transmutability. (This rule is
+//! distinct from type privacy, which still may forbid naming such types.)
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+
+ pub fn is_transmutable<Src, Dst, Context>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ // visibility is NOT assumed ---------------------------------^^^^^
+ {}
+}
+
+mod src {
+ #[repr(C)] pub(self) struct Zst; // <- unreachable type
+
+ #[repr(C)] pub(in super) struct Src {
+ pub(in super) field: Zst, //~ ERROR private type
+ }
+}
+
+mod dst {
+ #[repr(C)] pub(in super) struct Zst;
+
+ #[repr(C)] pub(in super) struct Dst {
+ pub(in super) field: Zst,
+ }
+}
+
+fn test() {
+ struct Context;
+ assert::is_transmutable::<src::Src, dst::Dst, Context>();
+}
diff --git a/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_field.stderr b/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_field.stderr
new file mode 100644
index 000000000..3f7d08d0a
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_field.stderr
@@ -0,0 +1,12 @@
+error[E0446]: private type `src::Zst` in public interface
+ --> $DIR/should_accept_if_src_has_unreachable_field.rs:23:9
+ |
+LL | #[repr(C)] pub(self) struct Zst; // <- unreachable type
+ | -------------------- `src::Zst` declared as private
+...
+LL | pub(in super) field: Zst,
+ | ^^^^^^^^^^^^^^^^^^^^^^^^ can't leak private type
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0446`.
diff --git a/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_ty.rs b/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_ty.rs
new file mode 100644
index 000000000..1943fb871
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_ty.rs
@@ -0,0 +1,39 @@
+//! The presence of an unreachable source type (i.e., the source type is
+//! private) does not affect transmutability. (This rule is distinct from type
+//! privacy, which still may forbid naming such types.)
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+
+ pub fn is_transmutable<Src, Dst, Context>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ // visibility is NOT assumed ---------------------------------^^^^^
+ {}
+}
+
+mod src {
+ #[repr(C)] pub(in super) struct Zst;
+
+ // unreachable type
+ #[repr(C)] pub(self) struct Src {
+ pub(in super) field: Zst,
+ }
+}
+
+mod dst {
+ #[repr(C)] pub(in super) struct Zst;
+
+ #[repr(C)] pub(in super) struct Dst {
+ pub(in super) field: Zst,
+ }
+}
+
+fn test() {
+ struct Context;
+ assert::is_transmutable::<src::Src, dst::Dst, Context>(); //~ ERROR `Src` is private
+}
diff --git a/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_ty.stderr b/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_ty.stderr
new file mode 100644
index 000000000..e961984e1
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/should_accept_if_src_has_unreachable_ty.stderr
@@ -0,0 +1,15 @@
+error[E0603]: struct `Src` is private
+ --> $DIR/should_accept_if_src_has_unreachable_ty.rs:38:36
+ |
+LL | assert::is_transmutable::<src::Src, dst::Dst, Context>();
+ | ^^^ private struct
+ |
+note: the struct `Src` is defined here
+ --> $DIR/should_accept_if_src_has_unreachable_ty.rs:23:16
+ |
+LL | #[repr(C)] pub(self) struct Src {
+ | ^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0603`.
diff --git a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_field.rs b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_field.rs
new file mode 100644
index 000000000..fcf3f3a52
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_field.rs
@@ -0,0 +1,37 @@
+//! Unless visibility is assumed, a transmutation should be rejected if the
+//! destination type contains a private field.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+
+ pub fn is_transmutable<Src, Dst, Context>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ // visibility is NOT assumed ---------------------------------^^^^^
+ {}
+}
+
+mod src {
+ #[repr(C)] pub(in super) struct Zst;
+
+ #[repr(C)] pub(in super) struct Src {
+ pub(in super) field: Zst,
+ }
+}
+
+mod dst {
+ #[repr(C)] pub(in super) struct Zst;
+
+ #[repr(C)] pub(in super) struct Dst {
+ pub(self) field: Zst, // <- private field
+ }
+}
+
+fn test() {
+ struct Context;
+ assert::is_transmutable::<src::Src, dst::Dst, Context>(); //~ ERROR cannot be safely transmuted
+}
diff --git a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_field.stderr b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_field.stderr
new file mode 100644
index 000000000..85124019e
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_field.stderr
@@ -0,0 +1,19 @@
+error[E0277]: `Src` cannot be safely transmuted into `Dst` in the defining scope of `test::Context`.
+ --> $DIR/should_reject_if_dst_has_private_field.rs:36:41
+ |
+LL | assert::is_transmutable::<src::Src, dst::Dst, Context>();
+ | ^^^^^^^^ `Src` cannot be safely transmuted into `Dst` in the defining scope of `test::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<Src, test::Context, false, false, false, false>` is not implemented for `Dst`
+note: required by a bound in `is_transmutable`
+ --> $DIR/should_reject_if_dst_has_private_field.rs:13:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_variant.rs b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_variant.rs
new file mode 100644
index 000000000..566b56467
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_variant.rs
@@ -0,0 +1,38 @@
+//! Unless visibility is assumed, a transmutation should be rejected if the
+//! destination type contains a private variant.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+
+ pub fn is_transmutable<Src, Dst, Context>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ // visibility is NOT assumed ---------------------------------^^^^^
+ {}
+}
+
+mod src {
+ #[repr(C)] pub(in super) struct Zst;
+
+ #[repr(C)] pub(in super) struct Src {
+ pub(in super) field: Zst,
+ }
+}
+
+mod dst {
+ #[derive(Copy, Clone)]
+ #[repr(C)] pub(in super) struct Zst;
+
+ #[repr(C)] pub(in super) union Dst {
+ pub(self) field: Zst, // <- private variant
+ }
+}
+
+fn test() {
+ struct Context;
+ assert::is_transmutable::<src::Src, dst::Dst, Context>(); //~ ERROR cannot be safely transmuted
+}
diff --git a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_variant.stderr b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_variant.stderr
new file mode 100644
index 000000000..0be564d93
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_private_variant.stderr
@@ -0,0 +1,19 @@
+error[E0277]: `Src` cannot be safely transmuted into `Dst` in the defining scope of `test::Context`.
+ --> $DIR/should_reject_if_dst_has_private_variant.rs:37:41
+ |
+LL | assert::is_transmutable::<src::Src, dst::Dst, Context>();
+ | ^^^^^^^^ `Src` cannot be safely transmuted into `Dst` in the defining scope of `test::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<Src, test::Context, false, false, false, false>` is not implemented for `Dst`
+note: required by a bound in `is_transmutable`
+ --> $DIR/should_reject_if_dst_has_private_variant.rs:13:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_tricky_unreachable_field.rs b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_tricky_unreachable_field.rs
new file mode 100644
index 000000000..35fff5966
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_tricky_unreachable_field.rs
@@ -0,0 +1,52 @@
+// check-pass
+//! NOTE: This test documents a known-bug in the implementation of the
+//! transmutability trait. Once fixed, the above "check-pass" header should be
+//! removed, and an "ERROR cannot be safely transmuted" annotation should be added at the end
+//! of the line starting with `assert::is_transmutable`.
+//!
+//! Unless visibility is assumed, a transmutation should be rejected if the
+//! destination type contains an unreachable field (e.g., a public field with a
+//! private type). (This rule is distinct from type privacy, which still may
+//! forbid naming such types.)
+//!
+//! This test exercises a tricky-to-implement instance of this principle: the
+//! "pub-in-priv trick". In the below example, the type `dst::private::Zst` is
+//! unreachable from `Context`. Consequently, the transmute from `Src` to `Dst`
+//! SHOULD be rejected.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+
+ pub fn is_transmutable<Src, Dst, Context>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ // visibility is NOT assumed ---------------------------------^^^^^
+ {}
+}
+
+mod src {
+ #[repr(C)] pub(in super) struct Zst;
+
+ #[repr(C)] pub(in super) struct Src {
+ pub(in super) field: Zst,
+ }
+}
+
+mod dst {
+ mod private {
+ #[repr(C)] pub struct Zst; // <- unreachable type
+ }
+
+ #[repr(C)] pub(in super) struct Dst {
+ pub(in super) field: private::Zst,
+ }
+}
+
+fn test() {
+ struct Context;
+ assert::is_transmutable::<src::Src, dst::Dst, Context>();
+}
diff --git a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_field.rs b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_field.rs
new file mode 100644
index 000000000..42799d803
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_field.rs
@@ -0,0 +1,39 @@
+//! Unless visibility is assumed, a transmutation should be rejected if the
+//! destination type contains an unreachable field (e.g., a public field with a
+//! private type). (This rule is distinct from type privacy, which still may
+//! forbid naming such types.)
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+
+ pub fn is_transmutable<Src, Dst, Context>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ // visibility is NOT assumed ---------------------------------^^^^^
+ {}
+}
+
+mod src {
+ #[repr(C)] pub(in super) struct Zst;
+
+ #[repr(C)] pub(in super) struct Src {
+ pub(in super) field: Zst,
+ }
+}
+
+mod dst {
+ #[repr(C)] pub(self) struct Zst; // <- unreachable type
+
+ #[repr(C)] pub(in super) struct Dst {
+ pub(in super) field: Zst,
+ }
+}
+
+fn test() {
+ struct Context;
+ assert::is_transmutable::<src::Src, dst::Dst, Context>(); //~ ERROR cannot be safely transmuted
+}
diff --git a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_field.stderr b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_field.stderr
new file mode 100644
index 000000000..95c68d452
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_field.stderr
@@ -0,0 +1,19 @@
+error[E0277]: `Src` cannot be safely transmuted into `Dst` in the defining scope of `test::Context`.
+ --> $DIR/should_reject_if_dst_has_unreachable_field.rs:38:41
+ |
+LL | assert::is_transmutable::<src::Src, dst::Dst, Context>();
+ | ^^^^^^^^ `Src` cannot be safely transmuted into `Dst` in the defining scope of `test::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<Src, test::Context, false, false, false, false>` is not implemented for `Dst`
+note: required by a bound in `is_transmutable`
+ --> $DIR/should_reject_if_dst_has_unreachable_field.rs:15:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_ty.rs b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_ty.rs
new file mode 100644
index 000000000..e13b32b30
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_ty.rs
@@ -0,0 +1,42 @@
+//! Unless visibility is assumed, a transmutation should be rejected if the
+//! destination type contains an unreachable field (e.g., a public field with a
+//! private type). (This rule is distinct from type privacy, which still may
+//! forbid naming such types.)
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code)]
+
+mod assert {
+ use std::mem::BikeshedIntrinsicFrom;
+
+ pub fn is_transmutable<Src, Dst, Context>()
+ where
+ Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ // visibility is NOT assumed ---------------------------------^^^^^
+ {}
+}
+
+mod src {
+ #[repr(C)] pub(in super) struct Zst;
+
+ #[repr(C)] pub(in super) struct Src {
+ pub(in super) field: Zst,
+ }
+}
+
+mod dst {
+ #[repr(C)] pub(in super) struct Zst;
+
+ // unreachable type
+ #[repr(C)] pub(self) struct Dst {
+ pub(in super) field: Zst,
+ }
+}
+
+fn test() {
+ struct Context;
+ assert::is_transmutable::<src::Src, dst::Dst, Context>();
+ //~^ ERROR `Dst` is private
+ //~| ERROR cannot be safely transmuted
+}
diff --git a/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_ty.stderr b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_ty.stderr
new file mode 100644
index 000000000..3391839e3
--- /dev/null
+++ b/src/test/ui/transmutability/visibility/should_reject_if_dst_has_unreachable_ty.stderr
@@ -0,0 +1,32 @@
+error[E0603]: struct `Dst` is private
+ --> $DIR/should_reject_if_dst_has_unreachable_ty.rs:39:46
+ |
+LL | assert::is_transmutable::<src::Src, dst::Dst, Context>();
+ | ^^^ private struct
+ |
+note: the struct `Dst` is defined here
+ --> $DIR/should_reject_if_dst_has_unreachable_ty.rs:32:16
+ |
+LL | #[repr(C)] pub(self) struct Dst {
+ | ^^^^^^^^^^^^^^^^^^^^
+
+error[E0277]: `Src` cannot be safely transmuted into `Dst` in the defining scope of `test::Context`.
+ --> $DIR/should_reject_if_dst_has_unreachable_ty.rs:39:41
+ |
+LL | assert::is_transmutable::<src::Src, dst::Dst, Context>();
+ | ^^^^^^^^ `Src` cannot be safely transmuted into `Dst` in the defining scope of `test::Context`.
+ |
+ = help: the trait `BikeshedIntrinsicFrom<Src, test::Context, false, false, false, false>` is not implemented for `Dst`
+note: required by a bound in `is_transmutable`
+ --> $DIR/should_reject_if_dst_has_unreachable_ty.rs:15:14
+ |
+LL | pub fn is_transmutable<Src, Dst, Context>()
+ | --------------- required by a bound in this
+LL | where
+LL | Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0277, E0603.
+For more information about an error, try `rustc --explain E0277`.