Adding upstream version 1.65.0+dfsg1.upstream/1.65.0+dfsg1

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

67 files changed, 1168 insertions, 688 deletions

diff --git a/src/test/ui/transmutability/abstraction/abstracted_assume.rs b/src/test/ui/transmutability/abstraction/abstracted_assume.rs
index 2abbbf3c1..0225c4230 100644
--- a/src/test/ui/transmutability/abstraction/abstracted_assume.rs
+++ b/src/test/ui/transmutability/abstraction/abstracted_assume.rs
@@ -3,6 +3,7 @@
 //! provided indirectly through an abstraction.
 
 #![crate_type = "lib"]
+#![feature(adt_const_params)]
 #![feature(transmutability)]
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
@@ -13,19 +14,13 @@ mod assert {
         Src,
         Dst,
         Context,
-        const ASSUME_ALIGNMENT: bool,
-        const ASSUME_LIFETIMES: bool,
-        const ASSUME_VALIDITY: bool,
-        const ASSUME_VISIBILITY: bool,
+        const ASSUME: std::mem::Assume,
     >()
     where
         Dst: BikeshedIntrinsicFrom<
             Src,
             Context,
-            ASSUME_ALIGNMENT,
-            ASSUME_LIFETIMES,
-            ASSUME_VALIDITY,
-            ASSUME_VISIBILITY,
+            ASSUME,
         >,
     {}
 }
@@ -35,7 +30,7 @@ fn direct() {
     #[repr(C)] struct Src;
     #[repr(C)] struct Dst;
 
-    assert::is_transmutable::<Src, Dst, Context, false, false, false, false>();
+    assert::is_transmutable::<Src, Dst, Context, { std::mem::Assume::NOTHING }>();
 }
 
 fn via_const() {
@@ -45,7 +40,7 @@ fn via_const() {
 
     const FALSE: bool = false;
 
-    assert::is_transmutable::<Src, Dst, Context, FALSE, FALSE, FALSE, FALSE>();
+    assert::is_transmutable::<Src, Dst, Context, { std::mem::Assume::NOTHING }>();
 }
 
 fn via_associated_const() {
@@ -65,9 +60,13 @@ fn via_associated_const() {
         Src,
         Dst,
         Context,
-        {Ty::FALSE},
-        {Ty::FALSE},
-        {Ty::FALSE},
-        {Ty::FALSE}
+        {
+            std::mem::Assume {
+                alignment: {Ty::FALSE},
+                lifetimes: {Ty::FALSE},
+                safety: {Ty::FALSE},
+                validity: {Ty::FALSE},
+            }
+        }
     >();
 }
diff --git a/src/test/ui/transmutability/abstraction/const_generic_fn.rs b/src/test/ui/transmutability/abstraction/const_generic_fn.rs
index 94c38bb28..e693a0957 100644
--- a/src/test/ui/transmutability/abstraction/const_generic_fn.rs
+++ b/src/test/ui/transmutability/abstraction/const_generic_fn.rs
@@ -6,13 +6,13 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, 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>
+        T: BikeshedIntrinsicFrom<[E; N], Context, { Assume::SAFETY }>,
+        [E; N]: BikeshedIntrinsicFrom<T, Context, { Assume::SAFETY }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/arrays/should_have_correct_length.rs b/src/test/ui/transmutability/arrays/should_have_correct_length.rs
index bfe6d830a..353797d0c 100644
--- a/src/test/ui/transmutability/arrays/should_have_correct_length.rs
+++ b/src/test/ui/transmutability/arrays/should_have_correct_length.rs
@@ -6,12 +6,12 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY.and(Assume::VALIDITY) }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/arrays/should_inherit_alignment.rs b/src/test/ui/transmutability/arrays/should_inherit_alignment.rs
index fcb1765ea..b00e5c7e4 100644
--- a/src/test/ui/transmutability/arrays/should_inherit_alignment.rs
+++ b/src/test/ui/transmutability/arrays/should_inherit_alignment.rs
@@ -6,12 +6,17 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume::ALIGNMENT
+                .and(Assume::LIFETIMES)
+                .and(Assume::SAFETY)
+                .and(Assume::VALIDITY)
+        }>
     {}
 }
 
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
index 8e69527c1..853bd9cbc 100644
--- a/src/test/ui/transmutability/arrays/should_require_well_defined_layout.rs
+++ b/src/test/ui/transmutability/arrays/should_require_well_defined_layout.rs
@@ -5,12 +5,17 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume::ALIGNMENT
+                .and(Assume::LIFETIMES)
+                .and(Assume::SAFETY)
+                .and(Assume::VALIDITY)
+        }>
     {}
 }
 
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
index eae0c947d..96a2fdc54 100644
--- a/src/test/ui/transmutability/arrays/should_require_well_defined_layout.stderr
+++ b/src/test/ui/transmutability/arrays/should_require_well_defined_layout.stderr
@@ -1,98 +1,134 @@
 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
+  --> $DIR/should_require_well_defined_layout.rs:26:52
    |
 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 `()`
+   = help: the trait `BikeshedIntrinsicFrom<[String; 0], assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume::ALIGNMENT
+LL | |                 .and(Assume::LIFETIMES)
+LL | |                 .and(Assume::SAFETY)
+LL | |                 .and(Assume::VALIDITY)
+LL | |         }>
+   | |__________^ 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
+  --> $DIR/should_require_well_defined_layout.rs:27:47
    |
 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]`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume::ALIGNMENT
+LL | |                 .and(Assume::LIFETIMES)
+LL | |                 .and(Assume::SAFETY)
+LL | |                 .and(Assume::VALIDITY)
+LL | |         }>
+   | |__________^ 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
+  --> $DIR/should_require_well_defined_layout.rs:32:52
    |
 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 `()`
+   = help: the trait `BikeshedIntrinsicFrom<[String; 1], assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume::ALIGNMENT
+LL | |                 .and(Assume::LIFETIMES)
+LL | |                 .and(Assume::SAFETY)
+LL | |                 .and(Assume::VALIDITY)
+LL | |         }>
+   | |__________^ 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
+  --> $DIR/should_require_well_defined_layout.rs:33:47
    |
 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]`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume::ALIGNMENT
+LL | |                 .and(Assume::LIFETIMES)
+LL | |                 .and(Assume::SAFETY)
+LL | |                 .and(Assume::VALIDITY)
+LL | |         }>
+   | |__________^ 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
+  --> $DIR/should_require_well_defined_layout.rs:38:52
    |
 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 `()`
+   = help: the trait `BikeshedIntrinsicFrom<[String; 2], assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume::ALIGNMENT
+LL | |                 .and(Assume::LIFETIMES)
+LL | |                 .and(Assume::SAFETY)
+LL | |                 .and(Assume::VALIDITY)
+LL | |         }>
+   | |__________^ 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
+  --> $DIR/should_require_well_defined_layout.rs:39:47
    |
 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]`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume::ALIGNMENT
+LL | |                 .and(Assume::LIFETIMES)
+LL | |                 .and(Assume::SAFETY)
+LL | |                 .and(Assume::VALIDITY)
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error: aborting due to 6 previous errors
 
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
index 18e02b0d2..940f070e7 100644
--- 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
@@ -5,11 +5,18 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
     {}
 }
 
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
index fa2e3b89b..4da5fcea3 100644
--- 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
@@ -1,322 +1,462 @@
 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
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:48:44
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<Zst, n8::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_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
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:50:44
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<V0i8, n8::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_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
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:56:44
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<Zst, n8::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_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
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:58:44
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<V0u8, n8::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_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
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:72:44
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u8, n16::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_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
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:74:44
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<V0i16, n16::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_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
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:80:44
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u8, n16::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_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
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:82:44
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<V0u16, n16::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_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
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:96:44
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u16, n32::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_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
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:98:44
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<V0i32, n32::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_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
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:104:44
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u16, n32::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_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
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:106:44
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<V0u32, n32::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_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
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:120:44
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u32, n64::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_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
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:122:44
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<V0i64, n64::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_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
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:128:44
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u32, n64::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_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
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:130:44
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<V0u64, n64::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_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
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:144:44
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u8, nsize::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_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
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:146:44
    |
 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]`
+   = help: the trait `BikeshedIntrinsicFrom<V0isize, nsize::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_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
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:152:44
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u8, nsize::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_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
+  --> $DIR/primitive_reprs_should_have_correct_length.rs:154:44
    |
 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]`
+   = help: the trait `BikeshedIntrinsicFrom<V0usize, nsize::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error: aborting due to 20 previous errors
 
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
index 978a12648..102111ae2 100644
--- 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
@@ -6,12 +6,19 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
     {}
 }
 
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
index 3273e87c8..510b8c56e 100644
--- 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
@@ -1,98 +1,140 @@
 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
+  --> $DIR/should_require_well_defined_layout.rs:28:52
    |
 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 `()`
+   = help: the trait `BikeshedIntrinsicFrom<void::repr_rust, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs: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`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `void::repr_rust` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:22:47
+  --> $DIR/should_require_well_defined_layout.rs:29:47
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `singleton::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:27:52
+  --> $DIR/should_require_well_defined_layout.rs:34:52
    |
 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 `()`
+   = help: the trait `BikeshedIntrinsicFrom<singleton::repr_rust, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs: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`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `singleton::repr_rust` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:28:47
+  --> $DIR/should_require_well_defined_layout.rs:35:47
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `duplex::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:33:52
+  --> $DIR/should_require_well_defined_layout.rs:40:52
    |
 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 `()`
+   = help: the trait `BikeshedIntrinsicFrom<duplex::repr_rust, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs: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`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `duplex::repr_rust` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:34:47
+  --> $DIR/should_require_well_defined_layout.rs:41:47
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error: aborting due to 6 previous errors
 
diff --git a/src/test/ui/transmutability/enums/should_order_correctly.rs b/src/test/ui/transmutability/enums/should_order_correctly.rs
index 6558d2658..b753cf0e6 100644
--- a/src/test/ui/transmutability/enums/should_order_correctly.rs
+++ b/src/test/ui/transmutability/enums/should_order_correctly.rs
@@ -7,12 +7,17 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume::ALIGNMENT
+                .and(Assume::LIFETIMES)
+                .and(Assume::SAFETY)
+                .and(Assume::VALIDITY)
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/enums/should_pad_variants.rs b/src/test/ui/transmutability/enums/should_pad_variants.rs
index 466b6c8a1..c077c52a3 100644
--- a/src/test/ui/transmutability/enums/should_pad_variants.rs
+++ b/src/test/ui/transmutability/enums/should_pad_variants.rs
@@ -6,11 +6,16 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume::ALIGNMENT
+                .and(Assume::LIFETIMES)
+                .and(Assume::SAFETY)
+                .and(Assume::VALIDITY)
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/enums/should_pad_variants.stderr b/src/test/ui/transmutability/enums/should_pad_variants.stderr
index 429f7211d..a823503d5 100644
--- a/src/test/ui/transmutability/enums/should_pad_variants.stderr
+++ b/src/test/ui/transmutability/enums/should_pad_variants.stderr
@@ -1,18 +1,24 @@
 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
+  --> $DIR/should_pad_variants.rs:44:36
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<Src, should_pad_variants::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume::ALIGNMENT
+LL | |                 .and(Assume::LIFETIMES)
+LL | |                 .and(Assume::SAFETY)
+LL | |                 .and(Assume::VALIDITY)
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/transmutability/enums/should_respect_endianness.rs b/src/test/ui/transmutability/enums/should_respect_endianness.rs
index 67a3c4e94..19ff69005 100644
--- a/src/test/ui/transmutability/enums/should_respect_endianness.rs
+++ b/src/test/ui/transmutability/enums/should_respect_endianness.rs
@@ -7,12 +7,17 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume::ALIGNMENT
+                .and(Assume::LIFETIMES)
+                .and(Assume::SAFETY)
+                .and(Assume::VALIDITY)
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/enums/should_respect_endianness.stderr b/src/test/ui/transmutability/enums/should_respect_endianness.stderr
index 78023cb37..fcb70813b 100644
--- a/src/test/ui/transmutability/enums/should_respect_endianness.stderr
+++ b/src/test/ui/transmutability/enums/should_respect_endianness.stderr
@@ -1,18 +1,24 @@
 error[E0277]: `Src` cannot be safely transmuted into `Unexpected` in the defining scope of `assert::Context`.
-  --> $DIR/should_respect_endianness.rs:32:36
+  --> $DIR/should_respect_endianness.rs:37:36
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<Src, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume::ALIGNMENT
+LL | |                 .and(Assume::LIFETIMES)
+LL | |                 .and(Assume::SAFETY)
+LL | |                 .and(Assume::VALIDITY)
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/transmutability/malformed-program-gracefulness/unknown_dst.rs b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_dst.rs
index e13462d39..b3a1e13b8 100644
--- a/src/test/ui/transmutability/malformed-program-gracefulness/unknown_dst.rs
+++ b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_dst.rs
@@ -10,7 +10,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+        Dst: BikeshedIntrinsicFrom<Src, Context>
     {}
 }
 
diff --git a/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src.rs b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src.rs
index dc51e2a8f..092b205b7 100644
--- a/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src.rs
+++ b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src.rs
@@ -10,7 +10,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+        Dst: BikeshedIntrinsicFrom<Src, Context>
     {}
 }
 
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
index 86fc8bd6b..ebe34e134 100644
--- a/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src_field.rs
+++ b/src/test/ui/transmutability/malformed-program-gracefulness/unknown_src_field.rs
@@ -10,7 +10,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+        Dst: BikeshedIntrinsicFrom<Src, Context>
     {}
 }
 
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
index bd36748e7..354abf99d 100644
--- a/src/test/ui/transmutability/malformed-program-gracefulness/wrong-type-assume.rs
+++ b/src/test/ui/transmutability/malformed-program-gracefulness/wrong-type-assume.rs
@@ -2,11 +2,13 @@
 //! provided.
 
 #![crate_type = "lib"]
+#![feature(adt_const_params)]
+#![feature(generic_const_exprs)]
 #![feature(transmutability)]
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
 
     pub fn is_transmutable<
         Src,
@@ -14,19 +16,34 @@ mod assert {
         Context,
         const ASSUME_ALIGNMENT: bool,
         const ASSUME_LIFETIMES: bool,
+        const ASSUME_SAFETY: bool,
         const ASSUME_VALIDITY: bool,
-        const ASSUME_VISIBILITY: bool,
     >()
     where
         Dst: BikeshedIntrinsicFrom<
             Src,
             Context,
-            ASSUME_ALIGNMENT,
-            ASSUME_LIFETIMES,
-            ASSUME_VALIDITY,
-            ASSUME_VISIBILITY,
+            { from_options(ASSUME_ALIGNMENT, ASSUME_LIFETIMES, ASSUME_SAFETY, ASSUME_VALIDITY) }
+            //~^ ERROR E0080
+            //~| ERROR E0080
+            //~| ERROR E0080
+            //~| ERROR E0080
         >,
     {}
+
+    const fn from_options(
+        alignment: bool,
+        lifetimes: bool,
+        safety: bool,
+        validity: bool,
+    ) -> Assume {
+        Assume {
+            alignment,
+            lifetimes,
+            safety,
+            validity,
+        }
+    }
 }
 
 fn test() {
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
index e1464e023..a258f2ece 100644
--- a/src/test/ui/transmutability/malformed-program-gracefulness/wrong-type-assume.stderr
+++ b/src/test/ui/transmutability/malformed-program-gracefulness/wrong-type-assume.stderr
@@ -1,27 +1,52 @@
 error[E0308]: mismatched types
-  --> $DIR/wrong-type-assume.rs:36:51
+  --> $DIR/wrong-type-assume.rs:53:51
    |
 LL |     assert::is_transmutable::<Src, Dst, Context, {0u8}, false, false, false>();
    |                                                   ^^^ expected `bool`, found `u8`
 
+error[E0080]: evaluation of `assert::is_transmutable::<test::Src, test::Dst, test::Context, {0u8}, false, false, false>::{constant#0}` failed
+  --> $DIR/wrong-type-assume.rs:26:15
+   |
+LL |             { from_options(ASSUME_ALIGNMENT, ASSUME_LIFETIMES, ASSUME_SAFETY, ASSUME_VALIDITY) }
+   |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ referenced constant has errors
+
 error[E0308]: mismatched types
-  --> $DIR/wrong-type-assume.rs:37:58
+  --> $DIR/wrong-type-assume.rs:54:58
    |
 LL |     assert::is_transmutable::<Src, Dst, Context, false, {0u8}, false, false>();
    |                                                          ^^^ expected `bool`, found `u8`
 
+error[E0080]: evaluation of `assert::is_transmutable::<test::Src, test::Dst, test::Context, false, {0u8}, false, false>::{constant#0}` failed
+  --> $DIR/wrong-type-assume.rs:26:15
+   |
+LL |             { from_options(ASSUME_ALIGNMENT, ASSUME_LIFETIMES, ASSUME_SAFETY, ASSUME_VALIDITY) }
+   |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ referenced constant has errors
+
 error[E0308]: mismatched types
-  --> $DIR/wrong-type-assume.rs:38:65
+  --> $DIR/wrong-type-assume.rs:55:65
    |
 LL |     assert::is_transmutable::<Src, Dst, Context, false, false, {0u8}, false>();
    |                                                                 ^^^ expected `bool`, found `u8`
 
+error[E0080]: evaluation of `assert::is_transmutable::<test::Src, test::Dst, test::Context, false, false, {0u8}, false>::{constant#0}` failed
+  --> $DIR/wrong-type-assume.rs:26:15
+   |
+LL |             { from_options(ASSUME_ALIGNMENT, ASSUME_LIFETIMES, ASSUME_SAFETY, ASSUME_VALIDITY) }
+   |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ referenced constant has errors
+
 error[E0308]: mismatched types
-  --> $DIR/wrong-type-assume.rs:39:72
+  --> $DIR/wrong-type-assume.rs:56:72
    |
 LL |     assert::is_transmutable::<Src, Dst, Context, false, false, false, {0u8}>();
    |                                                                        ^^^ expected `bool`, found `u8`
 
-error: aborting due to 4 previous errors
+error[E0080]: evaluation of `assert::is_transmutable::<test::Src, test::Dst, test::Context, false, false, false, {0u8}>::{constant#0}` failed
+  --> $DIR/wrong-type-assume.rs:26:15
+   |
+LL |             { from_options(ASSUME_ALIGNMENT, ASSUME_LIFETIMES, ASSUME_SAFETY, ASSUME_VALIDITY) }
+   |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ referenced constant has errors
+
+error: aborting due to 8 previous errors
 
-For more information about this error, try `rustc --explain E0308`.
+Some errors have detailed explanations: E0080, E0308.
+For more information about an error, try `rustc --explain E0080`.
diff --git a/src/test/ui/transmutability/primitives/bool.rs b/src/test/ui/transmutability/primitives/bool.rs
index 4f79bc253..eebb74fff 100644
--- a/src/test/ui/transmutability/primitives/bool.rs
+++ b/src/test/ui/transmutability/primitives/bool.rs
@@ -4,17 +4,17 @@
 #![allow(incomplete_features)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
     {}
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY.and(Assume::VALIDITY) }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/primitives/bool.stderr b/src/test/ui/transmutability/primitives/bool.stderr
index dc740251c..214b5e150 100644
--- a/src/test/ui/transmutability/primitives/bool.stderr
+++ b/src/test/ui/transmutability/primitives/bool.stderr
@@ -4,15 +4,15 @@ error[E0277]: `u8` cannot be safely transmuted into `bool` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: true, validity: false }>` 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/transmutability/primitives/numbers.rs b/src/test/ui/transmutability/primitives/numbers.rs
index a5f79065d..0df43d204 100644
--- a/src/test/ui/transmutability/primitives/numbers.rs
+++ b/src/test/ui/transmutability/primitives/numbers.rs
@@ -9,7 +9,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
+        Dst: BikeshedIntrinsicFrom<Src, Context>
     {}
 }
 
diff --git a/src/test/ui/transmutability/primitives/numbers.stderr b/src/test/ui/transmutability/primitives/numbers.stderr
index 9b802a444..7cb7ca8e6 100644
--- a/src/test/ui/transmutability/primitives/numbers.stderr
+++ b/src/test/ui/transmutability/primitives/numbers.stderr
@@ -4,15 +4,15 @@ error[E0277]: `i8` cannot be safely transmuted into `i16` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -20,15 +20,15 @@ error[E0277]: `i8` cannot be safely transmuted into `u16` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -36,15 +36,15 @@ error[E0277]: `i8` cannot be safely transmuted into `i32` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -52,15 +52,15 @@ error[E0277]: `i8` cannot be safely transmuted into `f32` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -68,15 +68,15 @@ error[E0277]: `i8` cannot be safely transmuted into `u32` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -84,15 +84,15 @@ error[E0277]: `i8` cannot be safely transmuted into `u64` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -100,15 +100,15 @@ error[E0277]: `i8` cannot be safely transmuted into `i64` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -116,15 +116,15 @@ error[E0277]: `i8` cannot be safely transmuted into `f64` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -132,15 +132,15 @@ error[E0277]: `i8` cannot be safely transmuted into `u128` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -148,15 +148,15 @@ error[E0277]: `i8` cannot be safely transmuted into `i128` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -164,15 +164,15 @@ error[E0277]: `u8` cannot be safely transmuted into `i16` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -180,15 +180,15 @@ error[E0277]: `u8` cannot be safely transmuted into `u16` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -196,15 +196,15 @@ error[E0277]: `u8` cannot be safely transmuted into `i32` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -212,15 +212,15 @@ error[E0277]: `u8` cannot be safely transmuted into `f32` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -228,15 +228,15 @@ error[E0277]: `u8` cannot be safely transmuted into `u32` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -244,15 +244,15 @@ error[E0277]: `u8` cannot be safely transmuted into `u64` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -260,15 +260,15 @@ error[E0277]: `u8` cannot be safely transmuted into `i64` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -276,15 +276,15 @@ error[E0277]: `u8` cannot be safely transmuted into `f64` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -292,15 +292,15 @@ error[E0277]: `u8` cannot be safely transmuted into `u128` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -308,15 +308,15 @@ error[E0277]: `u8` cannot be safely transmuted into `i128` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u8, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -324,15 +324,15 @@ error[E0277]: `i16` cannot be safely transmuted into `i32` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -340,15 +340,15 @@ error[E0277]: `i16` cannot be safely transmuted into `f32` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -356,15 +356,15 @@ error[E0277]: `i16` cannot be safely transmuted into `u32` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -372,15 +372,15 @@ error[E0277]: `i16` cannot be safely transmuted into `u64` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -388,15 +388,15 @@ error[E0277]: `i16` cannot be safely transmuted into `i64` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -404,15 +404,15 @@ error[E0277]: `i16` cannot be safely transmuted into `f64` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -420,15 +420,15 @@ error[E0277]: `i16` cannot be safely transmuted into `u128` in the defining scop
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -436,15 +436,15 @@ error[E0277]: `i16` cannot be safely transmuted into `i128` in the defining scop
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -452,15 +452,15 @@ error[E0277]: `u16` cannot be safely transmuted into `i32` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -468,15 +468,15 @@ error[E0277]: `u16` cannot be safely transmuted into `f32` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -484,15 +484,15 @@ error[E0277]: `u16` cannot be safely transmuted into `u32` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -500,15 +500,15 @@ error[E0277]: `u16` cannot be safely transmuted into `u64` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -516,15 +516,15 @@ error[E0277]: `u16` cannot be safely transmuted into `i64` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -532,15 +532,15 @@ error[E0277]: `u16` cannot be safely transmuted into `f64` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -548,15 +548,15 @@ error[E0277]: `u16` cannot be safely transmuted into `u128` in the defining scop
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -564,15 +564,15 @@ error[E0277]: `u16` cannot be safely transmuted into `i128` in the defining scop
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u16, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -580,15 +580,15 @@ error[E0277]: `i32` cannot be safely transmuted into `u64` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -596,15 +596,15 @@ error[E0277]: `i32` cannot be safely transmuted into `i64` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -612,15 +612,15 @@ error[E0277]: `i32` cannot be safely transmuted into `f64` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -628,15 +628,15 @@ error[E0277]: `i32` cannot be safely transmuted into `u128` in the defining scop
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -644,15 +644,15 @@ error[E0277]: `i32` cannot be safely transmuted into `i128` in the defining scop
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -660,15 +660,15 @@ error[E0277]: `f32` cannot be safely transmuted into `u64` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<f32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -676,15 +676,15 @@ error[E0277]: `f32` cannot be safely transmuted into `i64` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<f32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -692,15 +692,15 @@ error[E0277]: `f32` cannot be safely transmuted into `f64` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<f32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -708,15 +708,15 @@ error[E0277]: `f32` cannot be safely transmuted into `u128` in the defining scop
 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`
+   = help: the trait `BikeshedIntrinsicFrom<f32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -724,15 +724,15 @@ error[E0277]: `f32` cannot be safely transmuted into `i128` in the defining scop
 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`
+   = help: the trait `BikeshedIntrinsicFrom<f32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -740,15 +740,15 @@ error[E0277]: `u32` cannot be safely transmuted into `u64` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -756,15 +756,15 @@ error[E0277]: `u32` cannot be safely transmuted into `i64` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -772,15 +772,15 @@ error[E0277]: `u32` cannot be safely transmuted into `f64` in the defining scope
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -788,15 +788,15 @@ error[E0277]: `u32` cannot be safely transmuted into `u128` in the defining scop
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -804,15 +804,15 @@ error[E0277]: `u32` cannot be safely transmuted into `i128` in the defining scop
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u32, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -820,15 +820,15 @@ error[E0277]: `u64` cannot be safely transmuted into `u128` in the defining scop
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u64, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -836,15 +836,15 @@ error[E0277]: `u64` cannot be safely transmuted into `i128` in the defining scop
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u64, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -852,15 +852,15 @@ error[E0277]: `i64` cannot be safely transmuted into `u128` in the defining scop
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i64, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -868,15 +868,15 @@ error[E0277]: `i64` cannot be safely transmuted into `i128` in the defining scop
 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`
+   = help: the trait `BikeshedIntrinsicFrom<i64, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -884,15 +884,15 @@ error[E0277]: `f64` cannot be safely transmuted into `u128` in the defining scop
 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`
+   = help: the trait `BikeshedIntrinsicFrom<f64, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -900,15 +900,15 @@ error[E0277]: `f64` cannot be safely transmuted into `i128` in the defining scop
 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`
+   = help: the trait `BikeshedIntrinsicFrom<f64, assert::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error: aborting due to 57 previous errors
 
diff --git a/src/test/ui/transmutability/primitives/unit.rs b/src/test/ui/transmutability/primitives/unit.rs
index 86d474030..1975a61de 100644
--- a/src/test/ui/transmutability/primitives/unit.rs
+++ b/src/test/ui/transmutability/primitives/unit.rs
@@ -5,11 +5,16 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume::ALIGNMENT
+                .and(Assume::LIFETIMES)
+                .and(Assume::SAFETY)
+                .and(Assume::VALIDITY)
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/primitives/unit.stderr b/src/test/ui/transmutability/primitives/unit.stderr
index cf27c0d17..8cabe44a0 100644
--- a/src/test/ui/transmutability/primitives/unit.stderr
+++ b/src/test/ui/transmutability/primitives/unit.stderr
@@ -1,18 +1,24 @@
 error[E0277]: `()` cannot be safely transmuted into `u8` in the defining scope of `should_have_correct_size::Context`.
-  --> $DIR/unit.rs:23:35
+  --> $DIR/unit.rs:28:35
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<(), should_have_correct_size::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume::ALIGNMENT
+LL | |                 .and(Assume::LIFETIMES)
+LL | |                 .and(Assume::SAFETY)
+LL | |                 .and(Assume::VALIDITY)
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/transmutability/references.rs b/src/test/ui/transmutability/references.rs
index c6fd4c43e..af3ff0ec1 100644
--- a/src/test/ui/transmutability/references.rs
+++ b/src/test/ui/transmutability/references.rs
@@ -5,12 +5,19 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/references.stderr b/src/test/ui/transmutability/references.stderr
index b1359ea58..e9c7b144a 100644
--- a/src/test/ui/transmutability/references.stderr
+++ b/src/test/ui/transmutability/references.stderr
@@ -1,18 +1,25 @@
 error[E0277]: `&'static Unit` cannot be safely transmuted into `&'static Unit` in the defining scope of `assert::Context`.
-  --> $DIR/references.rs:19:37
+  --> $DIR/references.rs:26:52
    |
 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`.
+   |                                                    ^^^^^^^^^^^^^ `&'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`
+   = help: the trait `BikeshedIntrinsicFrom<&'static Unit, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/transmutability/structs/repr/should_handle_align.rs b/src/test/ui/transmutability/structs/repr/should_handle_align.rs
index 71720165a..ea9bf2a23 100644
--- a/src/test/ui/transmutability/structs/repr/should_handle_align.rs
+++ b/src/test/ui/transmutability/structs/repr/should_handle_align.rs
@@ -6,12 +6,19 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/structs/repr/should_handle_packed.rs b/src/test/ui/transmutability/structs/repr/should_handle_packed.rs
index ae8acf504..17dc995fc 100644
--- a/src/test/ui/transmutability/structs/repr/should_handle_packed.rs
+++ b/src/test/ui/transmutability/structs/repr/should_handle_packed.rs
@@ -6,12 +6,19 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
     {}
 }
 
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
index 556be989d..9a65b4d70 100644
--- 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
@@ -5,12 +5,19 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
     {}
 }
 
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
index 07355f7c2..621dbee84 100644
--- 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
@@ -1,194 +1,278 @@
 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
+  --> $DIR/should_require_well_defined_layout.rs:28:52
    |
 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 `()`
+   = help: the trait `BikeshedIntrinsicFrom<should_reject_repr_rust::unit::repr_rust, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `should_reject_repr_rust::unit::repr_rust` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:22:47
+  --> $DIR/should_require_well_defined_layout.rs:29:47
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `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
+  --> $DIR/should_require_well_defined_layout.rs:34:52
    |
 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 `()`
+   = help: the trait `BikeshedIntrinsicFrom<should_reject_repr_rust::tuple::repr_rust, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `should_reject_repr_rust::tuple::repr_rust` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:28:47
+  --> $DIR/should_require_well_defined_layout.rs:35:47
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `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
+  --> $DIR/should_require_well_defined_layout.rs:40:52
    |
 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 `()`
+   = help: the trait `BikeshedIntrinsicFrom<should_reject_repr_rust::braces::repr_rust, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `should_reject_repr_rust::braces::repr_rust` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:34:47
+  --> $DIR/should_require_well_defined_layout.rs:41:47
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `aligned::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:39:52
+  --> $DIR/should_require_well_defined_layout.rs:46:52
    |
 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 `()`
+   = help: the trait `BikeshedIntrinsicFrom<aligned::repr_rust, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `aligned::repr_rust` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:40:47
+  --> $DIR/should_require_well_defined_layout.rs:47:47
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `packed::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:45:52
+  --> $DIR/should_require_well_defined_layout.rs:52:52
    |
 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 `()`
+   = help: the trait `BikeshedIntrinsicFrom<packed::repr_rust, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `packed::repr_rust` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:46:47
+  --> $DIR/should_require_well_defined_layout.rs:53:47
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `nested::repr_c` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:52:49
+  --> $DIR/should_require_well_defined_layout.rs:59:49
    |
 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 `()`
+   = help: the trait `BikeshedIntrinsicFrom<nested::repr_c, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `nested::repr_c` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:53:47
+  --> $DIR/should_require_well_defined_layout.rs:60:47
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error: aborting due to 12 previous errors
 
diff --git a/src/test/ui/transmutability/structs/should_order_fields_correctly.rs b/src/test/ui/transmutability/structs/should_order_fields_correctly.rs
index db49b914f..28724562b 100644
--- a/src/test/ui/transmutability/structs/should_order_fields_correctly.rs
+++ b/src/test/ui/transmutability/structs/should_order_fields_correctly.rs
@@ -6,12 +6,17 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume::ALIGNMENT
+                .and(Assume::LIFETIMES)
+                .and(Assume::SAFETY)
+                .and(Assume::VALIDITY)
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/unions/boolish.rs b/src/test/ui/transmutability/unions/boolish.rs
index 975118b99..e469c4973 100644
--- a/src/test/ui/transmutability/unions/boolish.rs
+++ b/src/test/ui/transmutability/unions/boolish.rs
@@ -7,12 +7,12 @@
 #![allow(incomplete_features)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/unions/repr/should_handle_align.rs b/src/test/ui/transmutability/unions/repr/should_handle_align.rs
index e215799a2..09c13cc4d 100644
--- a/src/test/ui/transmutability/unions/repr/should_handle_align.rs
+++ b/src/test/ui/transmutability/unions/repr/should_handle_align.rs
@@ -6,12 +6,19 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/unions/repr/should_handle_packed.rs b/src/test/ui/transmutability/unions/repr/should_handle_packed.rs
index 34a53c7a8..24c2abd69 100644
--- a/src/test/ui/transmutability/unions/repr/should_handle_packed.rs
+++ b/src/test/ui/transmutability/unions/repr/should_handle_packed.rs
@@ -6,12 +6,19 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
     {}
 }
 
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
index cec8e389f..b1d5f71dc 100644
--- 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
@@ -5,12 +5,19 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
     {}
 }
 
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
index 2ed01b159..523bde85a 100644
--- 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
@@ -1,34 +1,48 @@
 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
+  --> $DIR/should_require_well_defined_layout.rs:30:48
    |
 LL |     assert::is_maybe_transmutable::<repr_rust, ()>();
    |                                                ^^ `should_reject_repr_rust::repr_rust` cannot be safely transmuted into `()` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<should_reject_repr_rust::repr_rust, assert::Context, true, true, true, true>` is not implemented for `()`
+   = help: the trait `BikeshedIntrinsicFrom<should_reject_repr_rust::repr_rust, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `()`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error[E0277]: `u128` cannot be safely transmuted into `should_reject_repr_rust::repr_rust` in the defining scope of `assert::Context`.
-  --> $DIR/should_require_well_defined_layout.rs:24:43
+  --> $DIR/should_require_well_defined_layout.rs:31:43
    |
 LL |     assert::is_maybe_transmutable::<u128, repr_rust>();
    |                                           ^^^^^^^^^ `u128` cannot be safely transmuted into `should_reject_repr_rust::repr_rust` in the defining scope of `assert::Context`.
    |
-   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, true, true, true, true>` is not implemented for `should_reject_repr_rust::repr_rust`
+   = help: the trait `BikeshedIntrinsicFrom<u128, assert::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: true }>` is not implemented for `should_reject_repr_rust::repr_rust`
 note: required by a bound in `is_maybe_transmutable`
   --> $DIR/should_require_well_defined_layout.rs:13:14
    |
-LL |     pub fn is_maybe_transmutable<Src, Dst>()
-   |            --------------------- required by a bound in this
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
+LL |       pub fn is_maybe_transmutable<Src, Dst>()
+   |              --------------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume {
+LL | |                 alignment: true,
+LL | |                 lifetimes: true,
+...  |
+LL | |             }
+LL | |         }>
+   | |__________^ required by this bound in `is_maybe_transmutable`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/transmutability/unions/should_pad_variants.rs b/src/test/ui/transmutability/unions/should_pad_variants.rs
index c4757900f..cabe54467 100644
--- a/src/test/ui/transmutability/unions/should_pad_variants.rs
+++ b/src/test/ui/transmutability/unions/should_pad_variants.rs
@@ -6,11 +6,16 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume::ALIGNMENT
+                .and(Assume::LIFETIMES)
+                .and(Assume::SAFETY)
+                .and(Assume::VALIDITY)
+        }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/unions/should_pad_variants.stderr b/src/test/ui/transmutability/unions/should_pad_variants.stderr
index 429f7211d..a823503d5 100644
--- a/src/test/ui/transmutability/unions/should_pad_variants.stderr
+++ b/src/test/ui/transmutability/unions/should_pad_variants.stderr
@@ -1,18 +1,24 @@
 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
+  --> $DIR/should_pad_variants.rs:44:36
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<Src, should_pad_variants::Context, Assume { alignment: true, lifetimes: true, safety: true, validity: 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`
+LL |       pub fn is_transmutable<Src, Dst, Context>()
+   |              --------------- required by a bound in this
+LL |       where
+LL |           Dst: BikeshedIntrinsicFrom<Src, Context, {
+   |  ______________^
+LL | |             Assume::ALIGNMENT
+LL | |                 .and(Assume::LIFETIMES)
+LL | |                 .and(Assume::SAFETY)
+LL | |                 .and(Assume::VALIDITY)
+LL | |         }>
+   | |__________^ required by this bound in `is_transmutable`
 
 error: aborting due to previous error
 
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
index 2493d7155..1007fdd79 100644
--- 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
@@ -7,13 +7,12 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, true, true>
-        // validity IS assumed --------------------------------^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY.and(Assume::VALIDITY) }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/unions/should_reject_contraction.rs b/src/test/ui/transmutability/unions/should_reject_contraction.rs
index e8138d0e0..a24dfccd3 100644
--- a/src/test/ui/transmutability/unions/should_reject_contraction.rs
+++ b/src/test/ui/transmutability/unions/should_reject_contraction.rs
@@ -5,12 +5,12 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/unions/should_reject_contraction.stderr b/src/test/ui/transmutability/unions/should_reject_contraction.stderr
index 99f589008..41f0cedc3 100644
--- a/src/test/ui/transmutability/unions/should_reject_contraction.stderr
+++ b/src/test/ui/transmutability/unions/should_reject_contraction.stderr
@@ -4,15 +4,15 @@ error[E0277]: `Superset` cannot be safely transmuted into `Subset` in the defini
 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`
+   = help: the trait `BikeshedIntrinsicFrom<Superset, assert::Context, Assume { alignment: false, lifetimes: false, safety: true, validity: false }>` 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/transmutability/unions/should_reject_disjoint.rs b/src/test/ui/transmutability/unions/should_reject_disjoint.rs
index 16160e29a..43aaa6905 100644
--- a/src/test/ui/transmutability/unions/should_reject_disjoint.rs
+++ b/src/test/ui/transmutability/unions/should_reject_disjoint.rs
@@ -5,13 +5,12 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_maybe_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, true, true>
-        // validity IS assumed --------------------------------^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY.and(Assume::VALIDITY) }>
     {}
 }
 
diff --git a/src/test/ui/transmutability/unions/should_reject_disjoint.stderr b/src/test/ui/transmutability/unions/should_reject_disjoint.stderr
index 5714e2bf3..4323f9740 100644
--- a/src/test/ui/transmutability/unions/should_reject_disjoint.stderr
+++ b/src/test/ui/transmutability/unions/should_reject_disjoint.stderr
@@ -1,34 +1,34 @@
 error[E0277]: `A` cannot be safely transmuted into `B` in the defining scope of `assert::Context`.
-  --> $DIR/should_reject_disjoint.rs:34:40
+  --> $DIR/should_reject_disjoint.rs:33:40
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<A, assert::Context, Assume { alignment: false, lifetimes: false, safety: true, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY.and(Assume::VALIDITY) }>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
+  --> $DIR/should_reject_disjoint.rs:34:40
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<B, assert::Context, Assume { alignment: false, lifetimes: false, safety: true, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY.and(Assume::VALIDITY) }>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_maybe_transmutable`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/transmutability/unions/should_reject_intersecting.rs b/src/test/ui/transmutability/unions/should_reject_intersecting.rs
index 58e399fb9..9cd4233ee 100644
--- a/src/test/ui/transmutability/unions/should_reject_intersecting.rs
+++ b/src/test/ui/transmutability/unions/should_reject_intersecting.rs
@@ -6,13 +6,13 @@
 #![allow(dead_code, incomplete_features, non_camel_case_types)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
     pub struct Context;
 
     pub fn is_transmutable<Src, Dst>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
-        // validity is NOT assumed ----------------------------^^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
+        // validity is NOT assumed --------------^^^^^^^^^^^^^^^^^^
     {}
 }
 
diff --git a/src/test/ui/transmutability/unions/should_reject_intersecting.stderr b/src/test/ui/transmutability/unions/should_reject_intersecting.stderr
index 92689a5f8..e009888ae 100644
--- a/src/test/ui/transmutability/unions/should_reject_intersecting.stderr
+++ b/src/test/ui/transmutability/unions/should_reject_intersecting.stderr
@@ -4,15 +4,15 @@ error[E0277]: `A` cannot be safely transmuted into `B` in the defining scope of
 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`
+   = help: the trait `BikeshedIntrinsicFrom<A, assert::Context, Assume { alignment: false, lifetimes: false, safety: true, validity: false }>` 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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
@@ -20,15 +20,15 @@ error[E0277]: `B` cannot be safely transmuted into `A` in the defining scope of
 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`
+   = help: the trait `BikeshedIntrinsicFrom<B, assert::Context, Assume { alignment: false, lifetimes: false, safety: true, validity: false }>` 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error: aborting due to 2 previous errors
 
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
index 5a8c81049..8a41669c6 100644
--- 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
@@ -7,12 +7,12 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
-        // visibility IS assumed -------------------------------------^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
+        // safety IS assumed --------------------^^^^^^^^^^^^^^^^^^
     {}
 }
 
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
index 77ab4fa6b..dd57b877d 100644
--- 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
@@ -7,12 +7,12 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
-        // visibility IS assumed -------------------------------------^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
+        // safety IS assumed --------------------^^^^^^^^^^^^^^^^^^
     {}
 }
 
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
index 2421b24cb..ebce8ce87 100644
--- 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
@@ -13,12 +13,12 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
-        // visibility IS assumed -------------------------------------^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
+        // safety IS assumed --------------------^^^^^^^^^^^^^^^^^^
     {}
 }
 
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
index 80b454fda..546fcbaa3 100644
--- 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
@@ -8,12 +8,12 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
-        // visibility IS assumed -------------------------------------^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
+        // safety IS assumed --------------------^^^^^^^^^^^^^^^^^^
     {}
 }
 
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
index 7c53c91e4..b9b74d183 100644
--- 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
@@ -8,12 +8,12 @@
 #![allow(dead_code)]
 
 mod assert {
-    use std::mem::BikeshedIntrinsicFrom;
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true>
-        // visibility IS assumed -------------------------------------^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context, { Assume::SAFETY }>
+        // safety IS assumed --------------------^^^^^^^^^^^^^^^^^^
     {}
 }
 
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
index c3f298f01..5a0df09d4 100644
--- 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
@@ -11,8 +11,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-        // visibility is NOT assumed ---------------------------------^^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
     {}
 }
 
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
index 73f6aece5..0f69630cc 100644
--- 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
@@ -11,8 +11,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-        // visibility is NOT assumed ---------------------------------^^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
     {}
 }
 
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
index 6d602601e..9c8345a8e 100644
--- 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
@@ -11,8 +11,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-        // visibility is NOT assumed ---------------------------------^^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
     {}
 }
 
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
index 3f7d08d0a..39b73302e 100644
--- 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
@@ -1,5 +1,5 @@
 error[E0446]: private type `src::Zst` in public interface
-  --> $DIR/should_accept_if_src_has_unreachable_field.rs:23:9
+  --> $DIR/should_accept_if_src_has_unreachable_field.rs:22:9
    |
 LL |     #[repr(C)] pub(self) struct Zst; // <- unreachable type
    |                -------------------- `src::Zst` declared as private
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
index 1943fb871..acf9f2302 100644
--- 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
@@ -11,8 +11,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-        // visibility is NOT assumed ---------------------------------^^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
     {}
 }
 
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
index e961984e1..76dc7f340 100644
--- 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
@@ -1,11 +1,11 @@
 error[E0603]: struct `Src` is private
-  --> $DIR/should_accept_if_src_has_unreachable_ty.rs:38:36
+  --> $DIR/should_accept_if_src_has_unreachable_ty.rs:37:36
    |
 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
+  --> $DIR/should_accept_if_src_has_unreachable_ty.rs:22:16
    |
 LL |     #[repr(C)] pub(self) struct Src {
    |                ^^^^^^^^^^^^^^^^^^^^
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
index fcf3f3a52..e8c3fbc9a 100644
--- 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
@@ -10,8 +10,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-        // visibility is NOT assumed ---------------------------------^^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
     {}
 }
 
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
index 85124019e..d5d6d431b 100644
--- 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
@@ -1,18 +1,18 @@
 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
+  --> $DIR/should_reject_if_dst_has_private_field.rs:35:41
    |
 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`
+   = help: the trait `BikeshedIntrinsicFrom<Src, test::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error: aborting due to previous error
 
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
index 566b56467..47bca27ab 100644
--- 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
@@ -10,8 +10,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-        // visibility is NOT assumed ---------------------------------^^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
     {}
 }
 
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
index 0be564d93..a1ca2ced5 100644
--- 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
@@ -1,18 +1,18 @@
 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
+  --> $DIR/should_reject_if_dst_has_private_variant.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`
+   = help: the trait `BikeshedIntrinsicFrom<Src, test::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error: aborting due to previous error
 
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
index 35fff5966..662c32af1 100644
--- 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
@@ -23,8 +23,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-        // visibility is NOT assumed ---------------------------------^^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
     {}
 }
 
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
index 42799d803..d7e21676f 100644
--- 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
@@ -12,8 +12,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-        // visibility is NOT assumed ---------------------------------^^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
     {}
 }
 
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
index 95c68d452..4e648664d 100644
--- 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
@@ -1,18 +1,18 @@
 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
+  --> $DIR/should_reject_if_dst_has_unreachable_field.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`
+   = help: the trait `BikeshedIntrinsicFrom<Src, test::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error: aborting due to previous error
 
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
index e13b32b30..c7b59f15b 100644
--- 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
@@ -12,8 +12,7 @@ mod assert {
 
     pub fn is_transmutable<Src, Dst, Context>()
     where
-        Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, false>
-        // visibility is NOT assumed ---------------------------------^^^^^
+        Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
     {}
 }
 
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
index 3391839e3..bd72d64cc 100644
--- 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
@@ -1,30 +1,30 @@
 error[E0603]: struct `Dst` is private
-  --> $DIR/should_reject_if_dst_has_unreachable_ty.rs:39:46
+  --> $DIR/should_reject_if_dst_has_unreachable_ty.rs:38:46
    |
 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
+  --> $DIR/should_reject_if_dst_has_unreachable_ty.rs:31:16
    |
 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
+  --> $DIR/should_reject_if_dst_has_unreachable_ty.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`
+   = help: the trait `BikeshedIntrinsicFrom<Src, test::Context, Assume { alignment: false, lifetimes: false, safety: false, validity: 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`
+LL |         Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
 
 error: aborting due to 2 previous errors