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

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

66 files changed, 618 insertions, 506 deletions

diff --git a/src/test/ui/consts/assert-type-intrinsics.rs b/src/test/ui/consts/assert-type-intrinsics.rs
index 38e5c454e..3ce3e1bdb 100644
--- a/src/test/ui/consts/assert-type-intrinsics.rs
+++ b/src/test/ui/consts/assert-type-intrinsics.rs
@@ -13,10 +13,10 @@ fn main() {
     const _BAD1: () = unsafe {
         MaybeUninit::<!>::uninit().assume_init();
     };
-    const _BAD2: () = unsafe {
+    const _BAD2: () = {
         intrinsics::assert_uninit_valid::<bool>();
     };
-    const _BAD3: () = unsafe {
+    const _BAD3: () = {
         intrinsics::assert_zero_valid::<&'static i32>();
     };
 }
diff --git a/src/test/ui/consts/assert-type-intrinsics.stderr b/src/test/ui/consts/assert-type-intrinsics.stderr
index f3b9170d4..6eab10197 100644
--- a/src/test/ui/consts/assert-type-intrinsics.stderr
+++ b/src/test/ui/consts/assert-type-intrinsics.stderr
@@ -13,7 +13,7 @@ LL |         MaybeUninit::<!>::uninit().assume_init();
 error: any use of this value will cause an error
   --> $DIR/assert-type-intrinsics.rs:17:9
    |
-LL |     const _BAD2: () = unsafe {
+LL |     const _BAD2: () = {
    |     ---------------
 LL |         intrinsics::assert_uninit_valid::<bool>();
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ aborted execution: attempted to leave type `bool` uninitialized, which is invalid
@@ -24,7 +24,7 @@ LL |         intrinsics::assert_uninit_valid::<bool>();
 error: any use of this value will cause an error
   --> $DIR/assert-type-intrinsics.rs:20:9
    |
-LL |     const _BAD3: () = unsafe {
+LL |     const _BAD3: () = {
    |     ---------------
 LL |         intrinsics::assert_zero_valid::<&'static i32>();
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ aborted execution: attempted to zero-initialize type `&i32`, which is invalid
@@ -51,7 +51,7 @@ Future breakage diagnostic:
 error: any use of this value will cause an error
   --> $DIR/assert-type-intrinsics.rs:17:9
    |
-LL |     const _BAD2: () = unsafe {
+LL |     const _BAD2: () = {
    |     ---------------
 LL |         intrinsics::assert_uninit_valid::<bool>();
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ aborted execution: attempted to leave type `bool` uninitialized, which is invalid
@@ -64,7 +64,7 @@ Future breakage diagnostic:
 error: any use of this value will cause an error
   --> $DIR/assert-type-intrinsics.rs:20:9
    |
-LL |     const _BAD3: () = unsafe {
+LL |     const _BAD3: () = {
    |     ---------------
 LL |         intrinsics::assert_zero_valid::<&'static i32>();
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ aborted execution: attempted to zero-initialize type `&i32`, which is invalid
diff --git a/src/test/ui/consts/const-block-const-bound.stderr b/src/test/ui/consts/const-block-const-bound.stderr
index 87ca771e5..b9c4d8866 100644
--- a/src/test/ui/consts/const-block-const-bound.stderr
+++ b/src/test/ui/consts/const-block-const-bound.stderr
@@ -2,7 +2,7 @@ error[E0277]: can't drop `UnconstDrop` in const contexts
   --> $DIR/const-block-const-bound.rs:20:11
    |
 LL |         f(UnconstDrop);
-   |         - ^^^^^^^^^^^ expected an implementor of trait `~const Destruct`
+   |         - ^^^^^^^^^^^ the trait `~const Destruct` is not implemented for `UnconstDrop`
    |         |
    |         required by a bound introduced by this call
    |
@@ -23,7 +23,7 @@ error[E0277]: can't drop `NonDrop` in const contexts
   --> $DIR/const-block-const-bound.rs:22:11
    |
 LL |         f(NonDrop);
-   |         - ^^^^^^^ expected an implementor of trait `~const Destruct`
+   |         - ^^^^^^^ the trait `~const Destruct` is not implemented for `NonDrop`
    |         |
    |         required by a bound introduced by this call
    |
diff --git a/src/test/ui/consts/const-blocks/fn-call-in-non-const.stderr b/src/test/ui/consts/const-blocks/fn-call-in-non-const.stderr
index 5306fed22..ee352700c 100644
--- a/src/test/ui/consts/const-blocks/fn-call-in-non-const.stderr
+++ b/src/test/ui/consts/const-blocks/fn-call-in-non-const.stderr
@@ -4,7 +4,7 @@ error[E0277]: the trait bound `Bar: Copy` is not satisfied
 LL |     let _: [Option<Bar>; 2] = [no_copy(); 2];
    |                                ^^^^^^^^^ the trait `Copy` is not implemented for `Bar`
    |
-   = note: required because of the requirements on the impl of `Copy` for `Option<Bar>`
+   = note: required for `Option<Bar>` to implement `Copy`
    = note: the `Copy` trait is required because this value will be copied for each element of the array
    = help: consider creating a new `const` item and initializing it with the result of the function call to be used in the repeat position, like `const VAL: Type = const_fn();` and `let x = [VAL; 42];`
    = help: create an inline `const` block, see RFC #2920 <https://github.com/rust-lang/rfcs/pull/2920> for more information
diff --git a/src/test/ui/consts/const-blocks/migrate-fail.stderr b/src/test/ui/consts/const-blocks/migrate-fail.stderr
index 803281c07..928ffd083 100644
--- a/src/test/ui/consts/const-blocks/migrate-fail.stderr
+++ b/src/test/ui/consts/const-blocks/migrate-fail.stderr
@@ -4,7 +4,7 @@ error[E0277]: the trait bound `Bar: Copy` is not satisfied
 LL |         let arr: [Option<Bar>; 2] = [x; 2];
    |                                      ^ the trait `Copy` is not implemented for `Bar`
    |
-   = note: required because of the requirements on the impl of `Copy` for `Option<Bar>`
+   = note: required for `Option<Bar>` to implement `Copy`
    = note: the `Copy` trait is required because this value will be copied for each element of the array
 help: consider annotating `Bar` with `#[derive(Copy)]`
    |
@@ -17,7 +17,7 @@ error[E0277]: the trait bound `Bar: Copy` is not satisfied
 LL |         let arr: [Option<Bar>; 2] = [x; 2];
    |                                      ^ the trait `Copy` is not implemented for `Bar`
    |
-   = note: required because of the requirements on the impl of `Copy` for `Option<Bar>`
+   = note: required for `Option<Bar>` to implement `Copy`
    = note: the `Copy` trait is required because this value will be copied for each element of the array
 help: consider annotating `Bar` with `#[derive(Copy)]`
    |
diff --git a/src/test/ui/consts/const-blocks/nll-fail.stderr b/src/test/ui/consts/const-blocks/nll-fail.stderr
index 8841af15d..fede00845 100644
--- a/src/test/ui/consts/const-blocks/nll-fail.stderr
+++ b/src/test/ui/consts/const-blocks/nll-fail.stderr
@@ -4,7 +4,7 @@ error[E0277]: the trait bound `Bar: Copy` is not satisfied
 LL |         let arr: [Option<Bar>; 2] = [x; 2];
    |                                      ^ the trait `Copy` is not implemented for `Bar`
    |
-   = note: required because of the requirements on the impl of `Copy` for `Option<Bar>`
+   = note: required for `Option<Bar>` to implement `Copy`
    = note: the `Copy` trait is required because this value will be copied for each element of the array
 help: consider annotating `Bar` with `#[derive(Copy)]`
    |
@@ -17,7 +17,7 @@ error[E0277]: the trait bound `Bar: Copy` is not satisfied
 LL |         let arr: [Option<Bar>; 2] = [x; 2];
    |                                      ^ the trait `Copy` is not implemented for `Bar`
    |
-   = note: required because of the requirements on the impl of `Copy` for `Option<Bar>`
+   = note: required for `Option<Bar>` to implement `Copy`
    = note: the `Copy` trait is required because this value will be copied for each element of the array
 help: consider annotating `Bar` with `#[derive(Copy)]`
    |
diff --git a/src/test/ui/consts/const-blocks/trait-error.stderr b/src/test/ui/consts/const-blocks/trait-error.stderr
index ece200ad1..b11dd4b80 100644
--- a/src/test/ui/consts/const-blocks/trait-error.stderr
+++ b/src/test/ui/consts/const-blocks/trait-error.stderr
@@ -4,7 +4,7 @@ error[E0277]: the trait bound `String: Copy` is not satisfied
 LL |     [Foo(String::new()); 4];
    |      ^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `String`
    |
-note: required because of the requirements on the impl of `Copy` for `Foo<String>`
+note: required for `Foo<String>` to implement `Copy`
   --> $DIR/trait-error.rs:1:10
    |
 LL | #[derive(Copy, Clone)]
diff --git a/src/test/ui/consts/const-err4.32bit.stderr b/src/test/ui/consts/const-err4.32bit.stderr
index a55384783..1cbf78173 100644
--- a/src/test/ui/consts/const-err4.32bit.stderr
+++ b/src/test/ui/consts/const-err4.32bit.stderr
@@ -1,13 +1,8 @@
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/const-err4.rs:9:11
+error[E0080]: evaluation of constant value failed
+  --> $DIR/const-err4.rs:9:21
    |
 LL |     Boo = [unsafe { Foo { b: () }.a }; 4][3],
-   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered uninitialized bytes, but expected initialized bytes
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 4, align: 4) {
-               __ __ __ __                                     │ ░░░░
-           }
+   |                     ^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/consts/const-err4.64bit.stderr b/src/test/ui/consts/const-err4.64bit.stderr
index 66bfc30c3..1cbf78173 100644
--- a/src/test/ui/consts/const-err4.64bit.stderr
+++ b/src/test/ui/consts/const-err4.64bit.stderr
@@ -1,13 +1,8 @@
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/const-err4.rs:9:11
+error[E0080]: evaluation of constant value failed
+  --> $DIR/const-err4.rs:9:21
    |
 LL |     Boo = [unsafe { Foo { b: () }.a }; 4][3],
-   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered uninitialized bytes, but expected initialized bytes
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 8, align: 8) {
-               __ __ __ __ __ __ __ __                         │ ░░░░░░░░
-           }
+   |                     ^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/consts/const-err4.rs b/src/test/ui/consts/const-err4.rs
index f0625faa8..107dc3f82 100644
--- a/src/test/ui/consts/const-err4.rs
+++ b/src/test/ui/consts/const-err4.rs
@@ -7,7 +7,8 @@ union Foo {
 
 enum Bar {
     Boo = [unsafe { Foo { b: () }.a }; 4][3],
-    //~^ ERROR it is undefined behavior to use this value
+    //~^ ERROR evaluation of constant value failed
+    //~| uninitialized
 }
 
 fn main() {
diff --git a/src/test/ui/consts/const-eval/const-pointer-values-in-various-types.64bit.stderr b/src/test/ui/consts/const-eval/const-pointer-values-in-various-types.64bit.stderr
index b7b00f7d7..12d5b7bd6 100644
--- a/src/test/ui/consts/const-eval/const-pointer-values-in-various-types.64bit.stderr
+++ b/src/test/ui/consts/const-eval/const-pointer-values-in-various-types.64bit.stderr
@@ -54,19 +54,14 @@ LL |     const I32_REF_U64_UNION: u64 = unsafe { Nonsense { int_32_ref: &3 }.uin
    = help: this code performed an operation that depends on the underlying bytes representing a pointer
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/const-pointer-values-in-various-types.rs:46:5
+error[E0080]: evaluation of constant value failed
+  --> $DIR/const-pointer-values-in-various-types.rs:46:47
    |
 LL |     const I32_REF_U128_UNION: u128 = unsafe { Nonsense { int_32_ref: &3 }.uint_128 };
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered uninitialized bytes, but expected initialized bytes
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 16, align: 8) {
-               __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ │ ░░░░░░░░░░░░░░░░
-           }
+   |                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:49:43
+  --> $DIR/const-pointer-values-in-various-types.rs:50:43
    |
 LL |     const I32_REF_I8_UNION: i8 = unsafe { Nonsense { int_32_ref: &3 }.int_8 };
    |     --------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -77,7 +72,7 @@ LL |     const I32_REF_I8_UNION: i8 = unsafe { Nonsense { int_32_ref: &3 }.int_8
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:53:45
+  --> $DIR/const-pointer-values-in-various-types.rs:54:45
    |
 LL |     const I32_REF_I16_UNION: i16 = unsafe { Nonsense { int_32_ref: &3 }.int_16 };
    |     ----------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -88,7 +83,7 @@ LL |     const I32_REF_I16_UNION: i16 = unsafe { Nonsense { int_32_ref: &3 }.int
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:57:45
+  --> $DIR/const-pointer-values-in-various-types.rs:58:45
    |
 LL |     const I32_REF_I32_UNION: i32 = unsafe { Nonsense { int_32_ref: &3 }.int_32 };
    |     ----------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -99,7 +94,7 @@ LL |     const I32_REF_I32_UNION: i32 = unsafe { Nonsense { int_32_ref: &3 }.int
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:61:45
+  --> $DIR/const-pointer-values-in-various-types.rs:62:45
    |
 LL |     const I32_REF_I64_UNION: i64 = unsafe { Nonsense { int_32_ref: &3 }.int_64 };
    |     ----------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -109,19 +104,14 @@ LL |     const I32_REF_I64_UNION: i64 = unsafe { Nonsense { int_32_ref: &3 }.int
    = help: this code performed an operation that depends on the underlying bytes representing a pointer
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/const-pointer-values-in-various-types.rs:65:5
+error[E0080]: evaluation of constant value failed
+  --> $DIR/const-pointer-values-in-various-types.rs:66:47
    |
 LL |     const I32_REF_I128_UNION: i128 = unsafe { Nonsense { int_32_ref: &3 }.int_128 };
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered uninitialized bytes, but expected initialized bytes
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 16, align: 8) {
-               __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ │ ░░░░░░░░░░░░░░░░
-           }
+   |                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:68:45
+  --> $DIR/const-pointer-values-in-various-types.rs:70:45
    |
 LL |     const I32_REF_F32_UNION: f32 = unsafe { Nonsense { int_32_ref: &3 }.float_32 };
    |     ----------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -132,7 +122,7 @@ LL |     const I32_REF_F32_UNION: f32 = unsafe { Nonsense { int_32_ref: &3 }.flo
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:72:45
+  --> $DIR/const-pointer-values-in-various-types.rs:74:45
    |
 LL |     const I32_REF_F64_UNION: f64 = unsafe { Nonsense { int_32_ref: &3 }.float_64 };
    |     ----------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -143,7 +133,7 @@ LL |     const I32_REF_F64_UNION: f64 = unsafe { Nonsense { int_32_ref: &3 }.flo
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:76:47
+  --> $DIR/const-pointer-values-in-various-types.rs:78:47
    |
 LL |     const I32_REF_BOOL_UNION: bool = unsafe { Nonsense { int_32_ref: &3 }.truthy_falsey };
    |     ------------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -154,7 +144,7 @@ LL |     const I32_REF_BOOL_UNION: bool = unsafe { Nonsense { int_32_ref: &3 }.t
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:80:47
+  --> $DIR/const-pointer-values-in-various-types.rs:82:47
    |
 LL |     const I32_REF_CHAR_UNION: char = unsafe { Nonsense { int_32_ref: &3 }.character };
    |     ------------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -165,7 +155,7 @@ LL |     const I32_REF_CHAR_UNION: char = unsafe { Nonsense { int_32_ref: &3 }.c
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:84:39
+  --> $DIR/const-pointer-values-in-various-types.rs:86:39
    |
 LL |     const STR_U8_UNION: u8 = unsafe { Nonsense { stringy: "3" }.uint_8 };
    |     ----------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -176,7 +166,7 @@ LL |     const STR_U8_UNION: u8 = unsafe { Nonsense { stringy: "3" }.uint_8 };
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:88:41
+  --> $DIR/const-pointer-values-in-various-types.rs:90:41
    |
 LL |     const STR_U16_UNION: u16 = unsafe { Nonsense { stringy: "3" }.uint_16 };
    |     ------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -187,7 +177,7 @@ LL |     const STR_U16_UNION: u16 = unsafe { Nonsense { stringy: "3" }.uint_16 }
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:92:41
+  --> $DIR/const-pointer-values-in-various-types.rs:94:41
    |
 LL |     const STR_U32_UNION: u32 = unsafe { Nonsense { stringy: "3" }.uint_32 };
    |     ------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -198,7 +188,7 @@ LL |     const STR_U32_UNION: u32 = unsafe { Nonsense { stringy: "3" }.uint_32 }
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:96:41
+  --> $DIR/const-pointer-values-in-various-types.rs:98:41
    |
 LL |     const STR_U64_UNION: u64 = unsafe { Nonsense { stringy: "3" }.uint_64 };
    |     ------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -209,7 +199,7 @@ LL |     const STR_U64_UNION: u64 = unsafe { Nonsense { stringy: "3" }.uint_64 }
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:100:43
+  --> $DIR/const-pointer-values-in-various-types.rs:102:43
    |
 LL |     const STR_U128_UNION: u128 = unsafe { Nonsense { stringy: "3" }.uint_128 };
    |     --------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -220,7 +210,7 @@ LL |     const STR_U128_UNION: u128 = unsafe { Nonsense { stringy: "3" }.uint_12
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:104:39
+  --> $DIR/const-pointer-values-in-various-types.rs:106:39
    |
 LL |     const STR_I8_UNION: i8 = unsafe { Nonsense { stringy: "3" }.int_8 };
    |     ----------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -231,7 +221,7 @@ LL |     const STR_I8_UNION: i8 = unsafe { Nonsense { stringy: "3" }.int_8 };
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:108:41
+  --> $DIR/const-pointer-values-in-various-types.rs:110:41
    |
 LL |     const STR_I16_UNION: i16 = unsafe { Nonsense { stringy: "3" }.int_16 };
    |     ------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -242,7 +232,7 @@ LL |     const STR_I16_UNION: i16 = unsafe { Nonsense { stringy: "3" }.int_16 };
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:112:41
+  --> $DIR/const-pointer-values-in-various-types.rs:114:41
    |
 LL |     const STR_I32_UNION: i32 = unsafe { Nonsense { stringy: "3" }.int_32 };
    |     ------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -253,7 +243,7 @@ LL |     const STR_I32_UNION: i32 = unsafe { Nonsense { stringy: "3" }.int_32 };
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:116:41
+  --> $DIR/const-pointer-values-in-various-types.rs:118:41
    |
 LL |     const STR_I64_UNION: i64 = unsafe { Nonsense { stringy: "3" }.int_64 };
    |     ------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -264,7 +254,7 @@ LL |     const STR_I64_UNION: i64 = unsafe { Nonsense { stringy: "3" }.int_64 };
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:120:43
+  --> $DIR/const-pointer-values-in-various-types.rs:122:43
    |
 LL |     const STR_I128_UNION: i128 = unsafe { Nonsense { stringy: "3" }.int_128 };
    |     --------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -275,7 +265,7 @@ LL |     const STR_I128_UNION: i128 = unsafe { Nonsense { stringy: "3" }.int_128
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:124:41
+  --> $DIR/const-pointer-values-in-various-types.rs:126:41
    |
 LL |     const STR_F32_UNION: f32 = unsafe { Nonsense { stringy: "3" }.float_32 };
    |     ------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -286,7 +276,7 @@ LL |     const STR_F32_UNION: f32 = unsafe { Nonsense { stringy: "3" }.float_32
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:128:41
+  --> $DIR/const-pointer-values-in-various-types.rs:130:41
    |
 LL |     const STR_F64_UNION: f64 = unsafe { Nonsense { stringy: "3" }.float_64 };
    |     ------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -297,7 +287,7 @@ LL |     const STR_F64_UNION: f64 = unsafe { Nonsense { stringy: "3" }.float_64
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:132:43
+  --> $DIR/const-pointer-values-in-various-types.rs:134:43
    |
 LL |     const STR_BOOL_UNION: bool = unsafe { Nonsense { stringy: "3" }.truthy_falsey };
    |     --------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -308,7 +298,7 @@ LL |     const STR_BOOL_UNION: bool = unsafe { Nonsense { stringy: "3" }.truthy_
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:136:43
+  --> $DIR/const-pointer-values-in-various-types.rs:138:43
    |
 LL |     const STR_CHAR_UNION: char = unsafe { Nonsense { stringy: "3" }.character };
    |     --------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -388,7 +378,7 @@ LL |     const I32_REF_U64_UNION: u64 = unsafe { Nonsense { int_32_ref: &3 }.uin
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:49:43
+  --> $DIR/const-pointer-values-in-various-types.rs:50:43
    |
 LL |     const I32_REF_I8_UNION: i8 = unsafe { Nonsense { int_32_ref: &3 }.int_8 };
    |     --------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -401,7 +391,7 @@ LL |     const I32_REF_I8_UNION: i8 = unsafe { Nonsense { int_32_ref: &3 }.int_8
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:53:45
+  --> $DIR/const-pointer-values-in-various-types.rs:54:45
    |
 LL |     const I32_REF_I16_UNION: i16 = unsafe { Nonsense { int_32_ref: &3 }.int_16 };
    |     ----------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -414,7 +404,7 @@ LL |     const I32_REF_I16_UNION: i16 = unsafe { Nonsense { int_32_ref: &3 }.int
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:57:45
+  --> $DIR/const-pointer-values-in-various-types.rs:58:45
    |
 LL |     const I32_REF_I32_UNION: i32 = unsafe { Nonsense { int_32_ref: &3 }.int_32 };
    |     ----------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -427,7 +417,7 @@ LL |     const I32_REF_I32_UNION: i32 = unsafe { Nonsense { int_32_ref: &3 }.int
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:61:45
+  --> $DIR/const-pointer-values-in-various-types.rs:62:45
    |
 LL |     const I32_REF_I64_UNION: i64 = unsafe { Nonsense { int_32_ref: &3 }.int_64 };
    |     ----------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -440,7 +430,7 @@ LL |     const I32_REF_I64_UNION: i64 = unsafe { Nonsense { int_32_ref: &3 }.int
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:68:45
+  --> $DIR/const-pointer-values-in-various-types.rs:70:45
    |
 LL |     const I32_REF_F32_UNION: f32 = unsafe { Nonsense { int_32_ref: &3 }.float_32 };
    |     ----------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -453,7 +443,7 @@ LL |     const I32_REF_F32_UNION: f32 = unsafe { Nonsense { int_32_ref: &3 }.flo
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:72:45
+  --> $DIR/const-pointer-values-in-various-types.rs:74:45
    |
 LL |     const I32_REF_F64_UNION: f64 = unsafe { Nonsense { int_32_ref: &3 }.float_64 };
    |     ----------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -466,7 +456,7 @@ LL |     const I32_REF_F64_UNION: f64 = unsafe { Nonsense { int_32_ref: &3 }.flo
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:76:47
+  --> $DIR/const-pointer-values-in-various-types.rs:78:47
    |
 LL |     const I32_REF_BOOL_UNION: bool = unsafe { Nonsense { int_32_ref: &3 }.truthy_falsey };
    |     ------------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -479,7 +469,7 @@ LL |     const I32_REF_BOOL_UNION: bool = unsafe { Nonsense { int_32_ref: &3 }.t
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:80:47
+  --> $DIR/const-pointer-values-in-various-types.rs:82:47
    |
 LL |     const I32_REF_CHAR_UNION: char = unsafe { Nonsense { int_32_ref: &3 }.character };
    |     ------------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -492,7 +482,7 @@ LL |     const I32_REF_CHAR_UNION: char = unsafe { Nonsense { int_32_ref: &3 }.c
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:84:39
+  --> $DIR/const-pointer-values-in-various-types.rs:86:39
    |
 LL |     const STR_U8_UNION: u8 = unsafe { Nonsense { stringy: "3" }.uint_8 };
    |     ----------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -505,7 +495,7 @@ LL |     const STR_U8_UNION: u8 = unsafe { Nonsense { stringy: "3" }.uint_8 };
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:88:41
+  --> $DIR/const-pointer-values-in-various-types.rs:90:41
    |
 LL |     const STR_U16_UNION: u16 = unsafe { Nonsense { stringy: "3" }.uint_16 };
    |     ------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -518,7 +508,7 @@ LL |     const STR_U16_UNION: u16 = unsafe { Nonsense { stringy: "3" }.uint_16 }
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:92:41
+  --> $DIR/const-pointer-values-in-various-types.rs:94:41
    |
 LL |     const STR_U32_UNION: u32 = unsafe { Nonsense { stringy: "3" }.uint_32 };
    |     ------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -531,7 +521,7 @@ LL |     const STR_U32_UNION: u32 = unsafe { Nonsense { stringy: "3" }.uint_32 }
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:96:41
+  --> $DIR/const-pointer-values-in-various-types.rs:98:41
    |
 LL |     const STR_U64_UNION: u64 = unsafe { Nonsense { stringy: "3" }.uint_64 };
    |     ------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -544,7 +534,7 @@ LL |     const STR_U64_UNION: u64 = unsafe { Nonsense { stringy: "3" }.uint_64 }
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:100:43
+  --> $DIR/const-pointer-values-in-various-types.rs:102:43
    |
 LL |     const STR_U128_UNION: u128 = unsafe { Nonsense { stringy: "3" }.uint_128 };
    |     --------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -557,7 +547,7 @@ LL |     const STR_U128_UNION: u128 = unsafe { Nonsense { stringy: "3" }.uint_12
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:104:39
+  --> $DIR/const-pointer-values-in-various-types.rs:106:39
    |
 LL |     const STR_I8_UNION: i8 = unsafe { Nonsense { stringy: "3" }.int_8 };
    |     ----------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -570,7 +560,7 @@ LL |     const STR_I8_UNION: i8 = unsafe { Nonsense { stringy: "3" }.int_8 };
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:108:41
+  --> $DIR/const-pointer-values-in-various-types.rs:110:41
    |
 LL |     const STR_I16_UNION: i16 = unsafe { Nonsense { stringy: "3" }.int_16 };
    |     ------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -583,7 +573,7 @@ LL |     const STR_I16_UNION: i16 = unsafe { Nonsense { stringy: "3" }.int_16 };
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:112:41
+  --> $DIR/const-pointer-values-in-various-types.rs:114:41
    |
 LL |     const STR_I32_UNION: i32 = unsafe { Nonsense { stringy: "3" }.int_32 };
    |     ------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -596,7 +586,7 @@ LL |     const STR_I32_UNION: i32 = unsafe { Nonsense { stringy: "3" }.int_32 };
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:116:41
+  --> $DIR/const-pointer-values-in-various-types.rs:118:41
    |
 LL |     const STR_I64_UNION: i64 = unsafe { Nonsense { stringy: "3" }.int_64 };
    |     ------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -609,7 +599,7 @@ LL |     const STR_I64_UNION: i64 = unsafe { Nonsense { stringy: "3" }.int_64 };
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:120:43
+  --> $DIR/const-pointer-values-in-various-types.rs:122:43
    |
 LL |     const STR_I128_UNION: i128 = unsafe { Nonsense { stringy: "3" }.int_128 };
    |     --------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -622,7 +612,7 @@ LL |     const STR_I128_UNION: i128 = unsafe { Nonsense { stringy: "3" }.int_128
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:124:41
+  --> $DIR/const-pointer-values-in-various-types.rs:126:41
    |
 LL |     const STR_F32_UNION: f32 = unsafe { Nonsense { stringy: "3" }.float_32 };
    |     ------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -635,7 +625,7 @@ LL |     const STR_F32_UNION: f32 = unsafe { Nonsense { stringy: "3" }.float_32
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:128:41
+  --> $DIR/const-pointer-values-in-various-types.rs:130:41
    |
 LL |     const STR_F64_UNION: f64 = unsafe { Nonsense { stringy: "3" }.float_64 };
    |     ------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -648,7 +638,7 @@ LL |     const STR_F64_UNION: f64 = unsafe { Nonsense { stringy: "3" }.float_64
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:132:43
+  --> $DIR/const-pointer-values-in-various-types.rs:134:43
    |
 LL |     const STR_BOOL_UNION: bool = unsafe { Nonsense { stringy: "3" }.truthy_falsey };
    |     --------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -661,7 +651,7 @@ LL |     const STR_BOOL_UNION: bool = unsafe { Nonsense { stringy: "3" }.truthy_
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/const-pointer-values-in-various-types.rs:136:43
+  --> $DIR/const-pointer-values-in-various-types.rs:138:43
    |
 LL |     const STR_CHAR_UNION: char = unsafe { Nonsense { stringy: "3" }.character };
    |     --------------------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
diff --git a/src/test/ui/consts/const-eval/const-pointer-values-in-various-types.rs b/src/test/ui/consts/const-eval/const-pointer-values-in-various-types.rs
index f10a67392..f6a5e4d3c 100644
--- a/src/test/ui/consts/const-eval/const-pointer-values-in-various-types.rs
+++ b/src/test/ui/consts/const-eval/const-pointer-values-in-various-types.rs
@@ -44,7 +44,8 @@ fn main() {
     //~| WARN this was previously accepted by the compiler but is being phased out
 
     const I32_REF_U128_UNION: u128 = unsafe { Nonsense { int_32_ref: &3 }.uint_128 };
-    //~^ ERROR it is undefined behavior to use this value
+    //~^ ERROR evaluation of constant value failed
+    //~| uninitialized
 
     const I32_REF_I8_UNION: i8 = unsafe { Nonsense { int_32_ref: &3 }.int_8 };
     //~^ ERROR any use of this value will cause an error
@@ -63,7 +64,8 @@ fn main() {
     //~| WARN this was previously accepted by the compiler but is being phased out
 
     const I32_REF_I128_UNION: i128 = unsafe { Nonsense { int_32_ref: &3 }.int_128 };
-    //~^ ERROR it is undefined behavior to use this value
+    //~^ ERROR evaluation of constant value failed
+    //~| uninitialized
 
     const I32_REF_F32_UNION: f32 = unsafe { Nonsense { int_32_ref: &3 }.float_32 };
     //~^ ERROR any use of this value will cause an error
diff --git a/src/test/ui/consts/const-eval/heap/alloc_intrinsic_uninit.32bit.stderr b/src/test/ui/consts/const-eval/heap/alloc_intrinsic_uninit.32bit.stderr
index f1a780926..a0f4519ea 100644
--- a/src/test/ui/consts/const-eval/heap/alloc_intrinsic_uninit.32bit.stderr
+++ b/src/test/ui/consts/const-eval/heap/alloc_intrinsic_uninit.32bit.stderr
@@ -2,7 +2,7 @@ error[E0080]: it is undefined behavior to use this value
   --> $DIR/alloc_intrinsic_uninit.rs:8:1
    |
 LL | const BAR: &i32 = unsafe { &*(intrinsics::const_allocate(4, 4) as *mut i32) };
-   | ^^^^^^^^^^^^^^^ constructing invalid value at .<deref>: encountered uninitialized bytes, but expected initialized bytes
+   | ^^^^^^^^^^^^^^^ constructing invalid value at .<deref>: encountered uninitialized memory, but expected an integer
    |
    = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
    = note: the raw bytes of the constant (size: 4, align: 4) {
diff --git a/src/test/ui/consts/const-eval/heap/alloc_intrinsic_uninit.64bit.stderr b/src/test/ui/consts/const-eval/heap/alloc_intrinsic_uninit.64bit.stderr
index 2eb401226..d2bffa425 100644
--- a/src/test/ui/consts/const-eval/heap/alloc_intrinsic_uninit.64bit.stderr
+++ b/src/test/ui/consts/const-eval/heap/alloc_intrinsic_uninit.64bit.stderr
@@ -2,7 +2,7 @@ error[E0080]: it is undefined behavior to use this value
   --> $DIR/alloc_intrinsic_uninit.rs:8:1
    |
 LL | const BAR: &i32 = unsafe { &*(intrinsics::const_allocate(4, 4) as *mut i32) };
-   | ^^^^^^^^^^^^^^^ constructing invalid value at .<deref>: encountered uninitialized bytes, but expected initialized bytes
+   | ^^^^^^^^^^^^^^^ constructing invalid value at .<deref>: encountered uninitialized memory, but expected an integer
    |
    = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
    = note: the raw bytes of the constant (size: 8, align: 8) {
diff --git a/src/test/ui/consts/const-eval/issue-91827-extern-types.rs b/src/test/ui/consts/const-eval/issue-91827-extern-types.rs
index e1f5e8ae1..43c99799f 100644
--- a/src/test/ui/consts/const-eval/issue-91827-extern-types.rs
+++ b/src/test/ui/consts/const-eval/issue-91827-extern-types.rs
@@ -3,7 +3,6 @@
 // Test that we can handle unsized types with an extern type tail part.
 // Regression test for issue #91827.
 
-#![feature(const_ptr_offset_from)]
 #![feature(extern_types)]
 
 use std::ptr::addr_of;
diff --git a/src/test/ui/consts/const-eval/ub-enum-overwrite.rs b/src/test/ui/consts/const-eval/ub-enum-overwrite.rs
index c56778492..086a1001d 100644
--- a/src/test/ui/consts/const-eval/ub-enum-overwrite.rs
+++ b/src/test/ui/consts/const-eval/ub-enum-overwrite.rs
@@ -6,12 +6,13 @@ enum E {
 }
 
 const _: u8 = {
-    //~^ ERROR is undefined behavior
     let mut e = E::A(1);
     let p = if let E::A(x) = &mut e { x as *mut u8 } else { unreachable!() };
     // Make sure overwriting `e` uninitializes other bytes
     e = E::B;
     unsafe { *p }
+    //~^ ERROR evaluation of constant value failed
+    //~| uninitialized
 };
 
 fn main() {}
diff --git a/src/test/ui/consts/const-eval/ub-enum-overwrite.stderr b/src/test/ui/consts/const-eval/ub-enum-overwrite.stderr
index 8560112ae..5750212b4 100644
--- a/src/test/ui/consts/const-eval/ub-enum-overwrite.stderr
+++ b/src/test/ui/consts/const-eval/ub-enum-overwrite.stderr
@@ -1,13 +1,8 @@
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-enum-overwrite.rs:8:1
+error[E0080]: evaluation of constant value failed
+  --> $DIR/ub-enum-overwrite.rs:13:14
    |
-LL | const _: u8 = {
-   | ^^^^^^^^^^^ constructing invalid value: encountered uninitialized bytes, but expected initialized bytes
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 1, align: 1) {
-               __                                              │ ░
-           }
+LL |     unsafe { *p }
+   |              ^^ using uninitialized data, but this operation requires initialized memory
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/consts/const-eval/ub-enum.32bit.stderr b/src/test/ui/consts/const-eval/ub-enum.32bit.stderr
index ce3bc9474..752fd01f3 100644
--- a/src/test/ui/consts/const-eval/ub-enum.32bit.stderr
+++ b/src/test/ui/consts/const-eval/ub-enum.32bit.stderr
@@ -65,19 +65,14 @@ LL | const BAD_ENUM2_WRAPPED: Wrap<Enum2> = unsafe { mem::transmute(&0) };
    = help: this code performed an operation that depends on the underlying bytes representing a pointer
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-enum.rs:59:1
+error[E0080]: evaluation of constant value failed
+  --> $DIR/ub-enum.rs:59:42
    |
 LL | const BAD_ENUM2_UNDEF : Enum2 = unsafe { MaybeUninit { uninit: () }.init };
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-tag>: encountered uninitialized bytes, but expected initialized bytes
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 4, align: 4) {
-               __ __ __ __                                     │ ░░░░
-           }
+   |                                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:63:1
+  --> $DIR/ub-enum.rs:64:1
    |
 LL | const BAD_ENUM2_OPTION_PTR: Option<Enum2> = unsafe { mem::transmute(&0) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -88,7 +83,7 @@ LL | const BAD_ENUM2_OPTION_PTR: Option<Enum2> = unsafe { mem::transmute(&0) };
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-enum.rs:81:1
+  --> $DIR/ub-enum.rs:82:1
    |
 LL | const BAD_UNINHABITED_VARIANT1: UninhDiscriminant = unsafe { mem::transmute(1u8) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-variant(B)>.0: encountered a value of the never type `!`
@@ -99,7 +94,7 @@ LL | const BAD_UNINHABITED_VARIANT1: UninhDiscriminant = unsafe { mem::transmute
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-enum.rs:83:1
+  --> $DIR/ub-enum.rs:84:1
    |
 LL | const BAD_UNINHABITED_VARIANT2: UninhDiscriminant = unsafe { mem::transmute(3u8) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-variant(D)>.0: encountered a value of uninhabited type Never
@@ -110,7 +105,7 @@ LL | const BAD_UNINHABITED_VARIANT2: UninhDiscriminant = unsafe { mem::transmute
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-enum.rs:91:1
+  --> $DIR/ub-enum.rs:92:1
    |
 LL | const BAD_OPTION_CHAR: Option<(char, char)> = Some(('x', unsafe { mem::transmute(!0u32) }));
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-variant(Some)>.0.1: encountered 0xffffffff, but expected a valid unicode scalar value (in `0..=0x10FFFF` but not in `0xD800..=0xDFFF`)
@@ -121,13 +116,13 @@ LL | const BAD_OPTION_CHAR: Option<(char, char)> = Some(('x', unsafe { mem::tran
            }
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-enum.rs:96:77
+  --> $DIR/ub-enum.rs:97:77
    |
 LL | const BAD_UNINHABITED_WITH_DATA1: Result<(i32, Never), (i32, !)> = unsafe { mem::transmute(0u64) };
    |                                                                             ^^^^^^^^^^^^^^^^^^^^ transmuting to uninhabited type
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-enum.rs:98:77
+  --> $DIR/ub-enum.rs:99:77
    |
 LL | const BAD_UNINHABITED_WITH_DATA2: Result<(i32, !), (i32, Never)> = unsafe { mem::transmute(0u64) };
    |                                                                             ^^^^^^^^^^^^^^^^^^^^ transmuting to uninhabited type
@@ -189,7 +184,7 @@ LL | const BAD_ENUM2_WRAPPED: Wrap<Enum2> = unsafe { mem::transmute(&0) };
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:63:1
+  --> $DIR/ub-enum.rs:64:1
    |
 LL | const BAD_ENUM2_OPTION_PTR: Option<Enum2> = unsafe { mem::transmute(&0) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
diff --git a/src/test/ui/consts/const-eval/ub-enum.64bit.stderr b/src/test/ui/consts/const-eval/ub-enum.64bit.stderr
index d8fc20c98..3f1546a27 100644
--- a/src/test/ui/consts/const-eval/ub-enum.64bit.stderr
+++ b/src/test/ui/consts/const-eval/ub-enum.64bit.stderr
@@ -65,19 +65,14 @@ LL | const BAD_ENUM2_WRAPPED: Wrap<Enum2> = unsafe { mem::transmute(&0) };
    = help: this code performed an operation that depends on the underlying bytes representing a pointer
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-enum.rs:59:1
+error[E0080]: evaluation of constant value failed
+  --> $DIR/ub-enum.rs:59:42
    |
 LL | const BAD_ENUM2_UNDEF : Enum2 = unsafe { MaybeUninit { uninit: () }.init };
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-tag>: encountered uninitialized bytes, but expected initialized bytes
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 8, align: 8) {
-               __ __ __ __ __ __ __ __                         │ ░░░░░░░░
-           }
+   |                                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:63:1
+  --> $DIR/ub-enum.rs:64:1
    |
 LL | const BAD_ENUM2_OPTION_PTR: Option<Enum2> = unsafe { mem::transmute(&0) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -88,7 +83,7 @@ LL | const BAD_ENUM2_OPTION_PTR: Option<Enum2> = unsafe { mem::transmute(&0) };
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-enum.rs:81:1
+  --> $DIR/ub-enum.rs:82:1
    |
 LL | const BAD_UNINHABITED_VARIANT1: UninhDiscriminant = unsafe { mem::transmute(1u8) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-variant(B)>.0: encountered a value of the never type `!`
@@ -99,7 +94,7 @@ LL | const BAD_UNINHABITED_VARIANT1: UninhDiscriminant = unsafe { mem::transmute
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-enum.rs:83:1
+  --> $DIR/ub-enum.rs:84:1
    |
 LL | const BAD_UNINHABITED_VARIANT2: UninhDiscriminant = unsafe { mem::transmute(3u8) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-variant(D)>.0: encountered a value of uninhabited type Never
@@ -110,7 +105,7 @@ LL | const BAD_UNINHABITED_VARIANT2: UninhDiscriminant = unsafe { mem::transmute
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-enum.rs:91:1
+  --> $DIR/ub-enum.rs:92:1
    |
 LL | const BAD_OPTION_CHAR: Option<(char, char)> = Some(('x', unsafe { mem::transmute(!0u32) }));
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-variant(Some)>.0.1: encountered 0xffffffff, but expected a valid unicode scalar value (in `0..=0x10FFFF` but not in `0xD800..=0xDFFF`)
@@ -121,13 +116,13 @@ LL | const BAD_OPTION_CHAR: Option<(char, char)> = Some(('x', unsafe { mem::tran
            }
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-enum.rs:96:77
+  --> $DIR/ub-enum.rs:97:77
    |
 LL | const BAD_UNINHABITED_WITH_DATA1: Result<(i32, Never), (i32, !)> = unsafe { mem::transmute(0u64) };
    |                                                                             ^^^^^^^^^^^^^^^^^^^^ transmuting to uninhabited type
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-enum.rs:98:77
+  --> $DIR/ub-enum.rs:99:77
    |
 LL | const BAD_UNINHABITED_WITH_DATA2: Result<(i32, !), (i32, Never)> = unsafe { mem::transmute(0u64) };
    |                                                                             ^^^^^^^^^^^^^^^^^^^^ transmuting to uninhabited type
@@ -189,7 +184,7 @@ LL | const BAD_ENUM2_WRAPPED: Wrap<Enum2> = unsafe { mem::transmute(&0) };
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-enum.rs:63:1
+  --> $DIR/ub-enum.rs:64:1
    |
 LL | const BAD_ENUM2_OPTION_PTR: Option<Enum2> = unsafe { mem::transmute(&0) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
diff --git a/src/test/ui/consts/const-eval/ub-enum.rs b/src/test/ui/consts/const-eval/ub-enum.rs
index d8d2a499b..d8dc6d057 100644
--- a/src/test/ui/consts/const-eval/ub-enum.rs
+++ b/src/test/ui/consts/const-eval/ub-enum.rs
@@ -57,7 +57,8 @@ union MaybeUninit<T: Copy> {
     init: T,
 }
 const BAD_ENUM2_UNDEF : Enum2 = unsafe { MaybeUninit { uninit: () }.init };
-//~^ ERROR is undefined behavior
+//~^ ERROR evaluation of constant value failed
+//~| uninitialized
 
 // Pointer value in an enum with a niche that is not just 0.
 const BAD_ENUM2_OPTION_PTR: Option<Enum2> = unsafe { mem::transmute(&0) };
@@ -92,7 +93,7 @@ const BAD_OPTION_CHAR: Option<(char, char)> = Some(('x', unsafe { mem::transmute
 //~^ ERROR is undefined behavior
 
 // All variants are uninhabited but also have data.
-// Use `0` as constant to make behavior endianess-independent.
+// Use `0` as constant to make behavior endianness-independent.
 const BAD_UNINHABITED_WITH_DATA1: Result<(i32, Never), (i32, !)> = unsafe { mem::transmute(0u64) };
 //~^ ERROR evaluation of constant value failed
 const BAD_UNINHABITED_WITH_DATA2: Result<(i32, !), (i32, Never)> = unsafe { mem::transmute(0u64) };
diff --git a/src/test/ui/consts/const-eval/ub-int-array.32bit.stderr b/src/test/ui/consts/const-eval/ub-int-array.32bit.stderr
index 8eece9e30..6100a98d1 100644
--- a/src/test/ui/consts/const-eval/ub-int-array.32bit.stderr
+++ b/src/test/ui/consts/const-eval/ub-int-array.32bit.stderr
@@ -1,35 +1,20 @@
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-int-array.rs:14:1
+error[E0080]: evaluation of constant value failed
+  --> $DIR/ub-int-array.rs:16:9
    |
-LL | const UNINIT_INT_0: [u32; 3] = unsafe {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at [0]: encountered uninitialized bytes
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 12, align: 4) {
-               __ __ __ __ 01 00 00 00 02 00 00 00             │ ░░░░........
-           }
+LL |         MaybeUninit { uninit: () }.init,
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-int-array.rs:23:1
-   |
-LL | const UNINIT_INT_1: [u32; 3] = unsafe {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at [1]: encountered uninitialized bytes
+error[E0080]: evaluation of constant value failed
+  --> $DIR/ub-int-array.rs:31:13
    |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 12, align: 4) {
-               00 00 00 00 01 __ 01 01 02 02 __ 02             │ .....░....░.
-           }
+LL |             MaybeUninit { uninit: () }.init,
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-int-array.rs:43:1
-   |
-LL | const UNINIT_INT_2: [u32; 3] = unsafe {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at [2]: encountered uninitialized bytes
+error[E0080]: evaluation of constant value failed
+  --> $DIR/ub-int-array.rs:57:13
    |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 12, align: 4) {
-               00 00 00 00 01 01 01 01 02 02 02 __             │ ...........░
-           }
+LL |             MaybeUninit { uninit: () }.init,
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/consts/const-eval/ub-int-array.64bit.stderr b/src/test/ui/consts/const-eval/ub-int-array.64bit.stderr
index 8eece9e30..6100a98d1 100644
--- a/src/test/ui/consts/const-eval/ub-int-array.64bit.stderr
+++ b/src/test/ui/consts/const-eval/ub-int-array.64bit.stderr
@@ -1,35 +1,20 @@
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-int-array.rs:14:1
+error[E0080]: evaluation of constant value failed
+  --> $DIR/ub-int-array.rs:16:9
    |
-LL | const UNINIT_INT_0: [u32; 3] = unsafe {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at [0]: encountered uninitialized bytes
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 12, align: 4) {
-               __ __ __ __ 01 00 00 00 02 00 00 00             │ ░░░░........
-           }
+LL |         MaybeUninit { uninit: () }.init,
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-int-array.rs:23:1
-   |
-LL | const UNINIT_INT_1: [u32; 3] = unsafe {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at [1]: encountered uninitialized bytes
+error[E0080]: evaluation of constant value failed
+  --> $DIR/ub-int-array.rs:31:13
    |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 12, align: 4) {
-               00 00 00 00 01 __ 01 01 02 02 __ 02             │ .....░....░.
-           }
+LL |             MaybeUninit { uninit: () }.init,
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-int-array.rs:43:1
-   |
-LL | const UNINIT_INT_2: [u32; 3] = unsafe {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at [2]: encountered uninitialized bytes
+error[E0080]: evaluation of constant value failed
+  --> $DIR/ub-int-array.rs:57:13
    |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 12, align: 4) {
-               00 00 00 00 01 01 01 01 02 02 02 __             │ ...........░
-           }
+LL |             MaybeUninit { uninit: () }.init,
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/consts/const-eval/ub-int-array.rs b/src/test/ui/consts/const-eval/ub-int-array.rs
index 1221f71d1..cb85e3b01 100644
--- a/src/test/ui/consts/const-eval/ub-int-array.rs
+++ b/src/test/ui/consts/const-eval/ub-int-array.rs
@@ -12,17 +12,15 @@ union MaybeUninit<T: Copy> {
 }
 
 const UNINIT_INT_0: [u32; 3] = unsafe {
-//~^ ERROR it is undefined behavior to use this value
-//~| constructing invalid value at [0]: encountered uninitialized bytes
     [
         MaybeUninit { uninit: () }.init,
+        //~^ ERROR evaluation of constant value failed
+        //~| uninitialized
         1,
         2,
     ]
 };
 const UNINIT_INT_1: [u32; 3] = unsafe {
-//~^ ERROR it is undefined behavior to use this value
-//~| constructing invalid value at [1]: encountered uninitialized bytes
     mem::transmute(
         [
             0u8,
@@ -31,6 +29,8 @@ const UNINIT_INT_1: [u32; 3] = unsafe {
             0u8,
             1u8,
             MaybeUninit { uninit: () }.init,
+            //~^ ERROR evaluation of constant value failed
+            //~| uninitialized
             1u8,
             1u8,
             2u8,
@@ -41,8 +41,6 @@ const UNINIT_INT_1: [u32; 3] = unsafe {
     )
 };
 const UNINIT_INT_2: [u32; 3] = unsafe {
-//~^ ERROR it is undefined behavior to use this value
-//~| constructing invalid value at [2]: encountered uninitialized bytes
     mem::transmute(
         [
             0u8,
@@ -57,6 +55,8 @@ const UNINIT_INT_2: [u32; 3] = unsafe {
             2u8,
             2u8,
             MaybeUninit { uninit: () }.init,
+            //~^ ERROR evaluation of constant value failed
+            //~| uninitialized
         ]
     )
 };
diff --git a/src/test/ui/consts/const-eval/ub-nonnull.32bit.stderr b/src/test/ui/consts/const-eval/ub-nonnull.32bit.stderr
index d450a814c..693c0e99b 100644
--- a/src/test/ui/consts/const-eval/ub-nonnull.32bit.stderr
+++ b/src/test/ui/consts/const-eval/ub-nonnull.32bit.stderr
@@ -37,19 +37,14 @@ LL | const NULL_USIZE: NonZeroUsize = unsafe { mem::transmute(0usize) };
                00 00 00 00                                     │ ....
            }
 
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-nonnull.rs:33:1
+error[E0080]: evaluation of constant value failed
+  --> $DIR/ub-nonnull.rs:33:36
    |
 LL | const UNINIT: NonZeroU8 = unsafe { MaybeUninit { uninit: () }.init };
-   | ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .0: encountered uninitialized bytes, but expected initialized bytes
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 1, align: 1) {
-               __                                              │ ░
-           }
+   |                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-nonnull.rs:41:1
+  --> $DIR/ub-nonnull.rs:42:1
    |
 LL | const BAD_RANGE1: RestrictedRange1 = unsafe { RestrictedRange1(42) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered 42, but expected something in the range 10..=30
@@ -60,7 +55,7 @@ LL | const BAD_RANGE1: RestrictedRange1 = unsafe { RestrictedRange1(42) };
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-nonnull.rs:47:1
+  --> $DIR/ub-nonnull.rs:48:1
    |
 LL | const BAD_RANGE2: RestrictedRange2 = unsafe { RestrictedRange2(20) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered 20, but expected something less or equal to 10, or greater or equal to 30
diff --git a/src/test/ui/consts/const-eval/ub-nonnull.64bit.stderr b/src/test/ui/consts/const-eval/ub-nonnull.64bit.stderr
index ed0d91aab..d22191213 100644
--- a/src/test/ui/consts/const-eval/ub-nonnull.64bit.stderr
+++ b/src/test/ui/consts/const-eval/ub-nonnull.64bit.stderr
@@ -37,19 +37,14 @@ LL | const NULL_USIZE: NonZeroUsize = unsafe { mem::transmute(0usize) };
                00 00 00 00 00 00 00 00                         │ ........
            }
 
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-nonnull.rs:33:1
+error[E0080]: evaluation of constant value failed
+  --> $DIR/ub-nonnull.rs:33:36
    |
 LL | const UNINIT: NonZeroU8 = unsafe { MaybeUninit { uninit: () }.init };
-   | ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .0: encountered uninitialized bytes, but expected initialized bytes
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 1, align: 1) {
-               __                                              │ ░
-           }
+   |                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-nonnull.rs:41:1
+  --> $DIR/ub-nonnull.rs:42:1
    |
 LL | const BAD_RANGE1: RestrictedRange1 = unsafe { RestrictedRange1(42) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered 42, but expected something in the range 10..=30
@@ -60,7 +55,7 @@ LL | const BAD_RANGE1: RestrictedRange1 = unsafe { RestrictedRange1(42) };
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-nonnull.rs:47:1
+  --> $DIR/ub-nonnull.rs:48:1
    |
 LL | const BAD_RANGE2: RestrictedRange2 = unsafe { RestrictedRange2(20) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered 20, but expected something less or equal to 10, or greater or equal to 30
diff --git a/src/test/ui/consts/const-eval/ub-nonnull.rs b/src/test/ui/consts/const-eval/ub-nonnull.rs
index 259707b80..777c6d988 100644
--- a/src/test/ui/consts/const-eval/ub-nonnull.rs
+++ b/src/test/ui/consts/const-eval/ub-nonnull.rs
@@ -31,7 +31,8 @@ union MaybeUninit<T: Copy> {
     init: T,
 }
 const UNINIT: NonZeroU8 = unsafe { MaybeUninit { uninit: () }.init };
-//~^ ERROR it is undefined behavior to use this value
+//~^ ERROR evaluation of constant value failed
+//~| uninitialized
 
 // Also test other uses of rustc_layout_scalar_valid_range_start
 
diff --git a/src/test/ui/consts/const-eval/ub-ref-ptr.32bit.stderr b/src/test/ui/consts/const-eval/ub-ref-ptr.32bit.stderr
index e86b37929..3e93219c8 100644
--- a/src/test/ui/consts/const-eval/ub-ref-ptr.32bit.stderr
+++ b/src/test/ui/consts/const-eval/ub-ref-ptr.32bit.stderr
@@ -116,19 +116,14 @@ LL | const USIZE_AS_BOX: Box<u8> = unsafe { mem::transmute(1337usize) };
                39 05 00 00                                     │ 9...
            }
 
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:53:1
+error[E0080]: evaluation of constant value failed
+  --> $DIR/ub-ref-ptr.rs:53:41
    |
 LL | const UNINIT_PTR: *const i32 = unsafe { MaybeUninit { uninit: () }.init };
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered uninitialized raw pointer
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 4, align: 4) {
-               __ __ __ __                                     │ ░░░░
-           }
+   |                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:56:1
+  --> $DIR/ub-ref-ptr.rs:57:1
    |
 LL | const NULL_FN_PTR: fn() = unsafe { mem::transmute(0usize) };
    | ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered null pointer, but expected a function pointer
@@ -138,19 +133,14 @@ LL | const NULL_FN_PTR: fn() = unsafe { mem::transmute(0usize) };
                00 00 00 00                                     │ ....
            }
 
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:58:1
+error[E0080]: evaluation of constant value failed
+  --> $DIR/ub-ref-ptr.rs:59:38
    |
 LL | const UNINIT_FN_PTR: fn() = unsafe { MaybeUninit { uninit: () }.init };
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered uninitialized bytes, but expected a proper pointer or integer value
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 4, align: 4) {
-               __ __ __ __                                     │ ░░░░
-           }
+   |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:60:1
+  --> $DIR/ub-ref-ptr.rs:62:1
    |
 LL | const DANGLING_FN_PTR: fn() = unsafe { mem::transmute(13usize) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered 0xd[noalloc], but expected a function pointer
@@ -161,7 +151,7 @@ LL | const DANGLING_FN_PTR: fn() = unsafe { mem::transmute(13usize) };
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:62:1
+  --> $DIR/ub-ref-ptr.rs:64:1
    |
 LL | const DATA_FN_PTR: fn() = unsafe { mem::transmute(&13) };
    | ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered alloc41, but expected a function pointer
diff --git a/src/test/ui/consts/const-eval/ub-ref-ptr.64bit.stderr b/src/test/ui/consts/const-eval/ub-ref-ptr.64bit.stderr
index eeec2dc4b..bc2aa12a2 100644
--- a/src/test/ui/consts/const-eval/ub-ref-ptr.64bit.stderr
+++ b/src/test/ui/consts/const-eval/ub-ref-ptr.64bit.stderr
@@ -116,19 +116,14 @@ LL | const USIZE_AS_BOX: Box<u8> = unsafe { mem::transmute(1337usize) };
                39 05 00 00 00 00 00 00                         │ 9.......
            }
 
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:53:1
+error[E0080]: evaluation of constant value failed
+  --> $DIR/ub-ref-ptr.rs:53:41
    |
 LL | const UNINIT_PTR: *const i32 = unsafe { MaybeUninit { uninit: () }.init };
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered uninitialized raw pointer
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 8, align: 8) {
-               __ __ __ __ __ __ __ __                         │ ░░░░░░░░
-           }
+   |                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:56:1
+  --> $DIR/ub-ref-ptr.rs:57:1
    |
 LL | const NULL_FN_PTR: fn() = unsafe { mem::transmute(0usize) };
    | ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered null pointer, but expected a function pointer
@@ -138,19 +133,14 @@ LL | const NULL_FN_PTR: fn() = unsafe { mem::transmute(0usize) };
                00 00 00 00 00 00 00 00                         │ ........
            }
 
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:58:1
+error[E0080]: evaluation of constant value failed
+  --> $DIR/ub-ref-ptr.rs:59:38
    |
 LL | const UNINIT_FN_PTR: fn() = unsafe { MaybeUninit { uninit: () }.init };
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered uninitialized bytes, but expected a proper pointer or integer value
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 8, align: 8) {
-               __ __ __ __ __ __ __ __                         │ ░░░░░░░░
-           }
+   |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:60:1
+  --> $DIR/ub-ref-ptr.rs:62:1
    |
 LL | const DANGLING_FN_PTR: fn() = unsafe { mem::transmute(13usize) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered 0xd[noalloc], but expected a function pointer
@@ -161,7 +151,7 @@ LL | const DANGLING_FN_PTR: fn() = unsafe { mem::transmute(13usize) };
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:62:1
+  --> $DIR/ub-ref-ptr.rs:64:1
    |
 LL | const DATA_FN_PTR: fn() = unsafe { mem::transmute(&13) };
    | ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered alloc41, but expected a function pointer
diff --git a/src/test/ui/consts/const-eval/ub-ref-ptr.rs b/src/test/ui/consts/const-eval/ub-ref-ptr.rs
index d0216f746..c62848f70 100644
--- a/src/test/ui/consts/const-eval/ub-ref-ptr.rs
+++ b/src/test/ui/consts/const-eval/ub-ref-ptr.rs
@@ -51,12 +51,14 @@ const USIZE_AS_BOX: Box<u8> = unsafe { mem::transmute(1337usize) };
 //~^ ERROR it is undefined behavior to use this value
 
 const UNINIT_PTR: *const i32 = unsafe { MaybeUninit { uninit: () }.init };
-//~^ ERROR it is undefined behavior to use this value
+//~^ ERROR evaluation of constant value failed
+//~| uninitialized
 
 const NULL_FN_PTR: fn() = unsafe { mem::transmute(0usize) };
 //~^ ERROR it is undefined behavior to use this value
 const UNINIT_FN_PTR: fn() = unsafe { MaybeUninit { uninit: () }.init };
-//~^ ERROR it is undefined behavior to use this value
+//~^ ERROR evaluation of constant value failed
+//~| uninitialized
 const DANGLING_FN_PTR: fn() = unsafe { mem::transmute(13usize) };
 //~^ ERROR it is undefined behavior to use this value
 const DATA_FN_PTR: fn() = unsafe { mem::transmute(&13) };
diff --git a/src/test/ui/consts/const-eval/ub-wide-ptr.32bit.stderr b/src/test/ui/consts/const-eval/ub-wide-ptr.32bit.stderr
index c4f0e3ab4..4cd974e7b 100644
--- a/src/test/ui/consts/const-eval/ub-wide-ptr.32bit.stderr
+++ b/src/test/ui/consts/const-eval/ub-wide-ptr.32bit.stderr
@@ -76,19 +76,14 @@ LL | const MYSTR_NO_INIT: &MyStr = unsafe { mem::transmute::<&[_], _>(&[MaybeUni
                ╾─allocN─╼ 01 00 00 00                         │ ╾──╼....
            }
 
-error[E0080]: it is undefined behavior to use this value
+error[E0080]: evaluation of constant value failed
   --> $DIR/ub-wide-ptr.rs:63:1
    |
 LL | const SLICE_LENGTH_UNINIT: &[u8] = unsafe {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered uninitialized reference
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 8, align: 4) {
-               2a 00 00 00 __ __ __ __                         │ *...░░░░
-           }
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:69:1
+  --> $DIR/ub-wide-ptr.rs:70:1
    |
 LL | const SLICE_TOO_LONG: &[u8] = unsafe { mem::transmute((&42u8, 999usize)) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a dangling reference (going beyond the bounds of its allocation)
@@ -99,7 +94,7 @@ LL | const SLICE_TOO_LONG: &[u8] = unsafe { mem::transmute((&42u8, 999usize)) };
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:72:1
+  --> $DIR/ub-wide-ptr.rs:73:1
    |
 LL | const SLICE_TOO_LONG_OVERFLOW: &[u32] = unsafe { mem::transmute((&42u32, isize::MAX)) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered invalid reference metadata: slice is bigger than largest supported object
@@ -110,7 +105,7 @@ LL | const SLICE_TOO_LONG_OVERFLOW: &[u32] = unsafe { mem::transmute((&42u32, is
            }
 
 error: any use of this value will cause an error
-  --> $DIR/ub-wide-ptr.rs:75:1
+  --> $DIR/ub-wide-ptr.rs:76:1
    |
 LL | const SLICE_LENGTH_PTR: &[u8] = unsafe { mem::transmute((&42u8, &3)) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -121,7 +116,7 @@ LL | const SLICE_LENGTH_PTR: &[u8] = unsafe { mem::transmute((&42u8, &3)) };
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:79:1
+  --> $DIR/ub-wide-ptr.rs:80:1
    |
 LL | const SLICE_TOO_LONG_BOX: Box<[u8]> = unsafe { mem::transmute((&42u8, 999usize)) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a dangling box (going beyond the bounds of its allocation)
@@ -132,7 +127,7 @@ LL | const SLICE_TOO_LONG_BOX: Box<[u8]> = unsafe { mem::transmute((&42u8, 999us
            }
 
 error: any use of this value will cause an error
-  --> $DIR/ub-wide-ptr.rs:82:1
+  --> $DIR/ub-wide-ptr.rs:83:1
    |
 LL | const SLICE_LENGTH_PTR_BOX: Box<[u8]> = unsafe { mem::transmute((&42u8, &3)) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -143,7 +138,7 @@ LL | const SLICE_LENGTH_PTR_BOX: Box<[u8]> = unsafe { mem::transmute((&42u8, &3)
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:87:1
+  --> $DIR/ub-wide-ptr.rs:88:1
    |
 LL | const SLICE_CONTENT_INVALID: &[bool] = &[unsafe { mem::transmute(3u8) }];
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<deref>[0]: encountered 0x03, but expected a boolean
@@ -154,7 +149,7 @@ LL | const SLICE_CONTENT_INVALID: &[bool] = &[unsafe { mem::transmute(3u8) }];
            }
 
 error: any use of this value will cause an error
-  --> $DIR/ub-wide-ptr.rs:87:40
+  --> $DIR/ub-wide-ptr.rs:88:40
    |
 LL | const SLICE_CONTENT_INVALID: &[bool] = &[unsafe { mem::transmute(3u8) }];
    | ------------------------------------   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ referenced constant has errors
@@ -163,7 +158,7 @@ LL | const SLICE_CONTENT_INVALID: &[bool] = &[unsafe { mem::transmute(3u8) }];
    = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:95:1
+  --> $DIR/ub-wide-ptr.rs:96:1
    |
 LL | const MYSLICE_PREFIX_BAD: &MySliceBool = &MySlice(unsafe { mem::transmute(3u8) }, [false]);
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<deref>.0: encountered 0x03, but expected a boolean
@@ -174,7 +169,7 @@ LL | const MYSLICE_PREFIX_BAD: &MySliceBool = &MySlice(unsafe { mem::transmute(3
            }
 
 error: any use of this value will cause an error
-  --> $DIR/ub-wide-ptr.rs:95:42
+  --> $DIR/ub-wide-ptr.rs:96:42
    |
 LL | const MYSLICE_PREFIX_BAD: &MySliceBool = &MySlice(unsafe { mem::transmute(3u8) }, [false]);
    | --------------------------------------   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ referenced constant has errors
@@ -183,7 +178,7 @@ LL | const MYSLICE_PREFIX_BAD: &MySliceBool = &MySlice(unsafe { mem::transmute(3
    = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:100:1
+  --> $DIR/ub-wide-ptr.rs:101:1
    |
 LL | const MYSLICE_SUFFIX_BAD: &MySliceBool = &MySlice(true, [unsafe { mem::transmute(3u8) }]);
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<deref>.1[0]: encountered 0x03, but expected a boolean
@@ -194,7 +189,7 @@ LL | const MYSLICE_SUFFIX_BAD: &MySliceBool = &MySlice(true, [unsafe { mem::tran
            }
 
 error: any use of this value will cause an error
-  --> $DIR/ub-wide-ptr.rs:100:42
+  --> $DIR/ub-wide-ptr.rs:101:42
    |
 LL | const MYSLICE_SUFFIX_BAD: &MySliceBool = &MySlice(true, [unsafe { mem::transmute(3u8) }]);
    | --------------------------------------   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ referenced constant has errors
@@ -202,19 +197,14 @@ LL | const MYSLICE_SUFFIX_BAD: &MySliceBool = &MySlice(true, [unsafe { mem::tran
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
 
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:109:1
+error[E0080]: evaluation of constant value failed
+  --> $DIR/ub-wide-ptr.rs:110:1
    |
 LL | const RAW_SLICE_LENGTH_UNINIT: *const [u8] = unsafe {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered uninitialized raw pointer
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 8, align: 4) {
-               2a 00 00 00 __ __ __ __                         │ *...░░░░
-           }
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:117:1
+  --> $DIR/ub-wide-ptr.rs:119:1
    |
 LL | const TRAIT_OBJ_SHORT_VTABLE_1: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, &3u8))) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .0: encountered allocN, but expected a vtable pointer
@@ -225,7 +215,7 @@ LL | const TRAIT_OBJ_SHORT_VTABLE_1: W<&dyn Trait> = unsafe { mem::transmute(W((
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:121:1
+  --> $DIR/ub-wide-ptr.rs:123:1
    |
 LL | const TRAIT_OBJ_SHORT_VTABLE_2: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, &3u64))) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .0: encountered allocN, but expected a vtable pointer
@@ -236,7 +226,7 @@ LL | const TRAIT_OBJ_SHORT_VTABLE_2: W<&dyn Trait> = unsafe { mem::transmute(W((
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:125:1
+  --> $DIR/ub-wide-ptr.rs:127:1
    |
 LL | const TRAIT_OBJ_INT_VTABLE: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, 4usize))) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .0: encountered 0x4[noalloc], but expected a vtable pointer
@@ -247,25 +237,25 @@ LL | const TRAIT_OBJ_INT_VTABLE: W<&dyn Trait> = unsafe { mem::transmute(W((&92u
            }
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-wide-ptr.rs:128:57
+  --> $DIR/ub-wide-ptr.rs:130:57
    |
 LL | const TRAIT_OBJ_UNALIGNED_VTABLE: &dyn Trait = unsafe { mem::transmute((&92u8, &[0u8; 128])) };
    |                                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using allocN as vtable pointer but it does not point to a vtable
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-wide-ptr.rs:131:57
+  --> $DIR/ub-wide-ptr.rs:133:57
    |
 LL | const TRAIT_OBJ_BAD_DROP_FN_NULL: &dyn Trait = unsafe { mem::transmute((&92u8, &[0usize; 8])) };
    |                                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using allocN as vtable pointer but it does not point to a vtable
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-wide-ptr.rs:134:56
+  --> $DIR/ub-wide-ptr.rs:136:56
    |
 LL | const TRAIT_OBJ_BAD_DROP_FN_INT: &dyn Trait = unsafe { mem::transmute((&92u8, &[1usize; 8])) };
    |                                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using allocN as vtable pointer but it does not point to a vtable
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:137:1
+  --> $DIR/ub-wide-ptr.rs:139:1
    |
 LL | const TRAIT_OBJ_BAD_DROP_FN_NOT_FN_PTR: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, &[&42u8; 8]))) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .0: encountered allocN, but expected a vtable pointer
@@ -276,7 +266,7 @@ LL | const TRAIT_OBJ_BAD_DROP_FN_NOT_FN_PTR: W<&dyn Trait> = unsafe { mem::trans
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:142:1
+  --> $DIR/ub-wide-ptr.rs:144:1
    |
 LL | const TRAIT_OBJ_CONTENT_INVALID: &dyn Trait = unsafe { mem::transmute::<_, &bool>(&3u8) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<deref>.<dyn-downcast>: encountered 0x03, but expected a boolean
@@ -286,17 +276,27 @@ LL | const TRAIT_OBJ_CONTENT_INVALID: &dyn Trait = unsafe { mem::transmute::<_,
                ╾allocN─╼ ╾allocN─╼                         │ ╾──╼╾──╼
            }
 
-error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-wide-ptr.rs:147:62
+error[E0080]: it is undefined behavior to use this value
+  --> $DIR/ub-wide-ptr.rs:149:1
    |
 LL | const RAW_TRAIT_OBJ_VTABLE_NULL: *const dyn Trait = unsafe { mem::transmute((&92u8, 0usize)) };
-   |                                                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ out-of-bounds pointer use: null pointer is a dangling pointer (it has no provenance)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered null pointer, but expected a vtable pointer
+   |
+   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
+   = note: the raw bytes of the constant (size: 8, align: 4) {
+               ╾allocN─╼ 00 00 00 00                         │ ╾──╼....
+           }
 
-error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-wide-ptr.rs:150:65
+error[E0080]: it is undefined behavior to use this value
+  --> $DIR/ub-wide-ptr.rs:151:1
    |
 LL | const RAW_TRAIT_OBJ_VTABLE_INVALID: *const dyn Trait = unsafe { mem::transmute((&92u8, &3u64)) };
-   |                                                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using allocN as vtable pointer but it does not point to a vtable
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered allocN, but expected a vtable pointer
+   |
+   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
+   = note: the raw bytes of the constant (size: 8, align: 4) {
+               ╾allocN─╼ ╾allocN─╼                         │ ╾──╼╾──╼
+           }
 
 error[E0080]: could not evaluate static initializer
   --> $DIR/ub-wide-ptr.rs:157:5
@@ -341,7 +341,7 @@ LL | const MY_STR_LENGTH_PTR: &MyStr = unsafe { mem::transmute((&42u8, &3)) };
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-wide-ptr.rs:75:1
+  --> $DIR/ub-wide-ptr.rs:76:1
    |
 LL | const SLICE_LENGTH_PTR: &[u8] = unsafe { mem::transmute((&42u8, &3)) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -354,7 +354,7 @@ LL | const SLICE_LENGTH_PTR: &[u8] = unsafe { mem::transmute((&42u8, &3)) };
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-wide-ptr.rs:82:1
+  --> $DIR/ub-wide-ptr.rs:83:1
    |
 LL | const SLICE_LENGTH_PTR_BOX: Box<[u8]> = unsafe { mem::transmute((&42u8, &3)) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -367,7 +367,7 @@ LL | const SLICE_LENGTH_PTR_BOX: Box<[u8]> = unsafe { mem::transmute((&42u8, &3)
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-wide-ptr.rs:87:40
+  --> $DIR/ub-wide-ptr.rs:88:40
    |
 LL | const SLICE_CONTENT_INVALID: &[bool] = &[unsafe { mem::transmute(3u8) }];
    | ------------------------------------   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ referenced constant has errors
@@ -378,7 +378,7 @@ LL | const SLICE_CONTENT_INVALID: &[bool] = &[unsafe { mem::transmute(3u8) }];
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-wide-ptr.rs:95:42
+  --> $DIR/ub-wide-ptr.rs:96:42
    |
 LL | const MYSLICE_PREFIX_BAD: &MySliceBool = &MySlice(unsafe { mem::transmute(3u8) }, [false]);
    | --------------------------------------   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ referenced constant has errors
@@ -389,7 +389,7 @@ LL | const MYSLICE_PREFIX_BAD: &MySliceBool = &MySlice(unsafe { mem::transmute(3
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-wide-ptr.rs:100:42
+  --> $DIR/ub-wide-ptr.rs:101:42
    |
 LL | const MYSLICE_SUFFIX_BAD: &MySliceBool = &MySlice(true, [unsafe { mem::transmute(3u8) }]);
    | --------------------------------------   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ referenced constant has errors
diff --git a/src/test/ui/consts/const-eval/ub-wide-ptr.64bit.stderr b/src/test/ui/consts/const-eval/ub-wide-ptr.64bit.stderr
index d6c612bb4..1d84b7bce 100644
--- a/src/test/ui/consts/const-eval/ub-wide-ptr.64bit.stderr
+++ b/src/test/ui/consts/const-eval/ub-wide-ptr.64bit.stderr
@@ -76,19 +76,14 @@ LL | const MYSTR_NO_INIT: &MyStr = unsafe { mem::transmute::<&[_], _>(&[MaybeUni
                ╾───────allocN───────╼ 01 00 00 00 00 00 00 00 │ ╾──────╼........
            }
 
-error[E0080]: it is undefined behavior to use this value
+error[E0080]: evaluation of constant value failed
   --> $DIR/ub-wide-ptr.rs:63:1
    |
 LL | const SLICE_LENGTH_UNINIT: &[u8] = unsafe {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered uninitialized reference
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 16, align: 8) {
-               __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ │ ░░░░░░░░░░░░░░░░
-           }
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:69:1
+  --> $DIR/ub-wide-ptr.rs:70:1
    |
 LL | const SLICE_TOO_LONG: &[u8] = unsafe { mem::transmute((&42u8, 999usize)) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a dangling reference (going beyond the bounds of its allocation)
@@ -99,7 +94,7 @@ LL | const SLICE_TOO_LONG: &[u8] = unsafe { mem::transmute((&42u8, 999usize)) };
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:72:1
+  --> $DIR/ub-wide-ptr.rs:73:1
    |
 LL | const SLICE_TOO_LONG_OVERFLOW: &[u32] = unsafe { mem::transmute((&42u32, isize::MAX)) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered invalid reference metadata: slice is bigger than largest supported object
@@ -110,7 +105,7 @@ LL | const SLICE_TOO_LONG_OVERFLOW: &[u32] = unsafe { mem::transmute((&42u32, is
            }
 
 error: any use of this value will cause an error
-  --> $DIR/ub-wide-ptr.rs:75:1
+  --> $DIR/ub-wide-ptr.rs:76:1
    |
 LL | const SLICE_LENGTH_PTR: &[u8] = unsafe { mem::transmute((&42u8, &3)) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -121,7 +116,7 @@ LL | const SLICE_LENGTH_PTR: &[u8] = unsafe { mem::transmute((&42u8, &3)) };
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:79:1
+  --> $DIR/ub-wide-ptr.rs:80:1
    |
 LL | const SLICE_TOO_LONG_BOX: Box<[u8]> = unsafe { mem::transmute((&42u8, 999usize)) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a dangling box (going beyond the bounds of its allocation)
@@ -132,7 +127,7 @@ LL | const SLICE_TOO_LONG_BOX: Box<[u8]> = unsafe { mem::transmute((&42u8, 999us
            }
 
 error: any use of this value will cause an error
-  --> $DIR/ub-wide-ptr.rs:82:1
+  --> $DIR/ub-wide-ptr.rs:83:1
    |
 LL | const SLICE_LENGTH_PTR_BOX: Box<[u8]> = unsafe { mem::transmute((&42u8, &3)) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -143,7 +138,7 @@ LL | const SLICE_LENGTH_PTR_BOX: Box<[u8]> = unsafe { mem::transmute((&42u8, &3)
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:87:1
+  --> $DIR/ub-wide-ptr.rs:88:1
    |
 LL | const SLICE_CONTENT_INVALID: &[bool] = &[unsafe { mem::transmute(3u8) }];
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<deref>[0]: encountered 0x03, but expected a boolean
@@ -154,7 +149,7 @@ LL | const SLICE_CONTENT_INVALID: &[bool] = &[unsafe { mem::transmute(3u8) }];
            }
 
 error: any use of this value will cause an error
-  --> $DIR/ub-wide-ptr.rs:87:40
+  --> $DIR/ub-wide-ptr.rs:88:40
    |
 LL | const SLICE_CONTENT_INVALID: &[bool] = &[unsafe { mem::transmute(3u8) }];
    | ------------------------------------   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ referenced constant has errors
@@ -163,7 +158,7 @@ LL | const SLICE_CONTENT_INVALID: &[bool] = &[unsafe { mem::transmute(3u8) }];
    = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:95:1
+  --> $DIR/ub-wide-ptr.rs:96:1
    |
 LL | const MYSLICE_PREFIX_BAD: &MySliceBool = &MySlice(unsafe { mem::transmute(3u8) }, [false]);
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<deref>.0: encountered 0x03, but expected a boolean
@@ -174,7 +169,7 @@ LL | const MYSLICE_PREFIX_BAD: &MySliceBool = &MySlice(unsafe { mem::transmute(3
            }
 
 error: any use of this value will cause an error
-  --> $DIR/ub-wide-ptr.rs:95:42
+  --> $DIR/ub-wide-ptr.rs:96:42
    |
 LL | const MYSLICE_PREFIX_BAD: &MySliceBool = &MySlice(unsafe { mem::transmute(3u8) }, [false]);
    | --------------------------------------   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ referenced constant has errors
@@ -183,7 +178,7 @@ LL | const MYSLICE_PREFIX_BAD: &MySliceBool = &MySlice(unsafe { mem::transmute(3
    = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:100:1
+  --> $DIR/ub-wide-ptr.rs:101:1
    |
 LL | const MYSLICE_SUFFIX_BAD: &MySliceBool = &MySlice(true, [unsafe { mem::transmute(3u8) }]);
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<deref>.1[0]: encountered 0x03, but expected a boolean
@@ -194,7 +189,7 @@ LL | const MYSLICE_SUFFIX_BAD: &MySliceBool = &MySlice(true, [unsafe { mem::tran
            }
 
 error: any use of this value will cause an error
-  --> $DIR/ub-wide-ptr.rs:100:42
+  --> $DIR/ub-wide-ptr.rs:101:42
    |
 LL | const MYSLICE_SUFFIX_BAD: &MySliceBool = &MySlice(true, [unsafe { mem::transmute(3u8) }]);
    | --------------------------------------   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ referenced constant has errors
@@ -202,19 +197,14 @@ LL | const MYSLICE_SUFFIX_BAD: &MySliceBool = &MySlice(true, [unsafe { mem::tran
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
 
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:109:1
+error[E0080]: evaluation of constant value failed
+  --> $DIR/ub-wide-ptr.rs:110:1
    |
 LL | const RAW_SLICE_LENGTH_UNINIT: *const [u8] = unsafe {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered uninitialized raw pointer
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 16, align: 8) {
-               __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ │ ░░░░░░░░░░░░░░░░
-           }
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:117:1
+  --> $DIR/ub-wide-ptr.rs:119:1
    |
 LL | const TRAIT_OBJ_SHORT_VTABLE_1: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, &3u8))) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .0: encountered allocN, but expected a vtable pointer
@@ -225,7 +215,7 @@ LL | const TRAIT_OBJ_SHORT_VTABLE_1: W<&dyn Trait> = unsafe { mem::transmute(W((
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:121:1
+  --> $DIR/ub-wide-ptr.rs:123:1
    |
 LL | const TRAIT_OBJ_SHORT_VTABLE_2: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, &3u64))) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .0: encountered allocN, but expected a vtable pointer
@@ -236,7 +226,7 @@ LL | const TRAIT_OBJ_SHORT_VTABLE_2: W<&dyn Trait> = unsafe { mem::transmute(W((
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:125:1
+  --> $DIR/ub-wide-ptr.rs:127:1
    |
 LL | const TRAIT_OBJ_INT_VTABLE: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, 4usize))) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .0: encountered 0x4[noalloc], but expected a vtable pointer
@@ -247,25 +237,25 @@ LL | const TRAIT_OBJ_INT_VTABLE: W<&dyn Trait> = unsafe { mem::transmute(W((&92u
            }
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-wide-ptr.rs:128:57
+  --> $DIR/ub-wide-ptr.rs:130:57
    |
 LL | const TRAIT_OBJ_UNALIGNED_VTABLE: &dyn Trait = unsafe { mem::transmute((&92u8, &[0u8; 128])) };
    |                                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using allocN as vtable pointer but it does not point to a vtable
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-wide-ptr.rs:131:57
+  --> $DIR/ub-wide-ptr.rs:133:57
    |
 LL | const TRAIT_OBJ_BAD_DROP_FN_NULL: &dyn Trait = unsafe { mem::transmute((&92u8, &[0usize; 8])) };
    |                                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using allocN as vtable pointer but it does not point to a vtable
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-wide-ptr.rs:134:56
+  --> $DIR/ub-wide-ptr.rs:136:56
    |
 LL | const TRAIT_OBJ_BAD_DROP_FN_INT: &dyn Trait = unsafe { mem::transmute((&92u8, &[1usize; 8])) };
    |                                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using allocN as vtable pointer but it does not point to a vtable
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:137:1
+  --> $DIR/ub-wide-ptr.rs:139:1
    |
 LL | const TRAIT_OBJ_BAD_DROP_FN_NOT_FN_PTR: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, &[&42u8; 8]))) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .0: encountered allocN, but expected a vtable pointer
@@ -276,7 +266,7 @@ LL | const TRAIT_OBJ_BAD_DROP_FN_NOT_FN_PTR: W<&dyn Trait> = unsafe { mem::trans
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-wide-ptr.rs:142:1
+  --> $DIR/ub-wide-ptr.rs:144:1
    |
 LL | const TRAIT_OBJ_CONTENT_INVALID: &dyn Trait = unsafe { mem::transmute::<_, &bool>(&3u8) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<deref>.<dyn-downcast>: encountered 0x03, but expected a boolean
@@ -286,17 +276,27 @@ LL | const TRAIT_OBJ_CONTENT_INVALID: &dyn Trait = unsafe { mem::transmute::<_,
                ╾──────allocN───────╼ ╾──────allocN───────╼ │ ╾──────╼╾──────╼
            }
 
-error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-wide-ptr.rs:147:62
+error[E0080]: it is undefined behavior to use this value
+  --> $DIR/ub-wide-ptr.rs:149:1
    |
 LL | const RAW_TRAIT_OBJ_VTABLE_NULL: *const dyn Trait = unsafe { mem::transmute((&92u8, 0usize)) };
-   |                                                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ out-of-bounds pointer use: null pointer is a dangling pointer (it has no provenance)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered null pointer, but expected a vtable pointer
+   |
+   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
+   = note: the raw bytes of the constant (size: 16, align: 8) {
+               ╾──────allocN───────╼ 00 00 00 00 00 00 00 00 │ ╾──────╼........
+           }
 
-error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-wide-ptr.rs:150:65
+error[E0080]: it is undefined behavior to use this value
+  --> $DIR/ub-wide-ptr.rs:151:1
    |
 LL | const RAW_TRAIT_OBJ_VTABLE_INVALID: *const dyn Trait = unsafe { mem::transmute((&92u8, &3u64)) };
-   |                                                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using allocN as vtable pointer but it does not point to a vtable
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered allocN, but expected a vtable pointer
+   |
+   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
+   = note: the raw bytes of the constant (size: 16, align: 8) {
+               ╾──────allocN───────╼ ╾──────allocN───────╼ │ ╾──────╼╾──────╼
+           }
 
 error[E0080]: could not evaluate static initializer
   --> $DIR/ub-wide-ptr.rs:157:5
@@ -341,7 +341,7 @@ LL | const MY_STR_LENGTH_PTR: &MyStr = unsafe { mem::transmute((&42u8, &3)) };
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-wide-ptr.rs:75:1
+  --> $DIR/ub-wide-ptr.rs:76:1
    |
 LL | const SLICE_LENGTH_PTR: &[u8] = unsafe { mem::transmute((&42u8, &3)) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -354,7 +354,7 @@ LL | const SLICE_LENGTH_PTR: &[u8] = unsafe { mem::transmute((&42u8, &3)) };
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-wide-ptr.rs:82:1
+  --> $DIR/ub-wide-ptr.rs:83:1
    |
 LL | const SLICE_LENGTH_PTR_BOX: Box<[u8]> = unsafe { mem::transmute((&42u8, &3)) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -367,7 +367,7 @@ LL | const SLICE_LENGTH_PTR_BOX: Box<[u8]> = unsafe { mem::transmute((&42u8, &3)
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-wide-ptr.rs:87:40
+  --> $DIR/ub-wide-ptr.rs:88:40
    |
 LL | const SLICE_CONTENT_INVALID: &[bool] = &[unsafe { mem::transmute(3u8) }];
    | ------------------------------------   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ referenced constant has errors
@@ -378,7 +378,7 @@ LL | const SLICE_CONTENT_INVALID: &[bool] = &[unsafe { mem::transmute(3u8) }];
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-wide-ptr.rs:95:42
+  --> $DIR/ub-wide-ptr.rs:96:42
    |
 LL | const MYSLICE_PREFIX_BAD: &MySliceBool = &MySlice(unsafe { mem::transmute(3u8) }, [false]);
    | --------------------------------------   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ referenced constant has errors
@@ -389,7 +389,7 @@ LL | const MYSLICE_PREFIX_BAD: &MySliceBool = &MySlice(unsafe { mem::transmute(3
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ub-wide-ptr.rs:100:42
+  --> $DIR/ub-wide-ptr.rs:101:42
    |
 LL | const MYSLICE_SUFFIX_BAD: &MySliceBool = &MySlice(true, [unsafe { mem::transmute(3u8) }]);
    | --------------------------------------   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ referenced constant has errors
diff --git a/src/test/ui/consts/const-eval/ub-wide-ptr.rs b/src/test/ui/consts/const-eval/ub-wide-ptr.rs
index a0377ab1e..788403a6d 100644
--- a/src/test/ui/consts/const-eval/ub-wide-ptr.rs
+++ b/src/test/ui/consts/const-eval/ub-wide-ptr.rs
@@ -61,7 +61,8 @@ const MYSTR_NO_INIT: &MyStr = unsafe { mem::transmute::<&[_], _>(&[MaybeUninit::
 const SLICE_VALID: &[u8] = unsafe { mem::transmute((&42u8, 1usize)) };
 // bad slice: length uninit
 const SLICE_LENGTH_UNINIT: &[u8] = unsafe {
-//~^ ERROR it is undefined behavior to use this value
+//~^ ERROR evaluation of constant value failed
+//~| uninitialized
     let uninit_len = MaybeUninit::<usize> { uninit: () };
     mem::transmute((42, uninit_len))
 };
@@ -107,7 +108,8 @@ const RAW_SLICE_VALID: *const [u8] = unsafe { mem::transmute((&42u8, 1usize)) };
 const RAW_SLICE_TOO_LONG: *const [u8] = unsafe { mem::transmute((&42u8, 999usize)) }; // ok because raw
 const RAW_SLICE_MUCH_TOO_LONG: *const [u8] = unsafe { mem::transmute((&42u8, usize::MAX)) }; // ok because raw
 const RAW_SLICE_LENGTH_UNINIT: *const [u8] = unsafe {
-//~^ ERROR it is undefined behavior to use this value
+//~^ ERROR evaluation of constant value failed
+//~| uninitialized
     let uninit_len = MaybeUninit::<usize> { uninit: () };
     mem::transmute((42, uninit_len))
 };
@@ -145,11 +147,9 @@ const TRAIT_OBJ_CONTENT_INVALID: &dyn Trait = unsafe { mem::transmute::<_, &bool
 
 // # raw trait object
 const RAW_TRAIT_OBJ_VTABLE_NULL: *const dyn Trait = unsafe { mem::transmute((&92u8, 0usize)) };
-//~^ ERROR evaluation of constant value failed
-//~| null pointer
+//~^ ERROR it is undefined behavior to use this value
 const RAW_TRAIT_OBJ_VTABLE_INVALID: *const dyn Trait = unsafe { mem::transmute((&92u8, &3u64)) };
-//~^ ERROR evaluation of constant value failed
-//~| does not point to a vtable
+//~^ ERROR it is undefined behavior to use this value
 const RAW_TRAIT_OBJ_CONTENT_INVALID: *const dyn Trait = unsafe { mem::transmute::<_, &bool>(&3u8) } as *const dyn Trait; // ok because raw
 
 // Const eval fails for these, so they need to be statics to error.
diff --git a/src/test/ui/consts/const-eval/union-const-eval-field.rs b/src/test/ui/consts/const-eval/union-const-eval-field.rs
index a1e48cac4..d88bf2a84 100644
--- a/src/test/ui/consts/const-eval/union-const-eval-field.rs
+++ b/src/test/ui/consts/const-eval/union-const-eval-field.rs
@@ -26,7 +26,8 @@ const fn read_field2() -> Field2 {
 
 const fn read_field3() -> Field3 {
     const FIELD3: Field3 = unsafe { UNION.field3 };
-    //~^ ERROR it is undefined behavior to use this value
+    //~^ ERROR evaluation of constant value failed
+    //~| uninitialized
     FIELD3
     //~^ ERROR erroneous constant used [E0080]
 }
diff --git a/src/test/ui/consts/const-eval/union-const-eval-field.stderr b/src/test/ui/consts/const-eval/union-const-eval-field.stderr
index c512e6825..00964489e 100644
--- a/src/test/ui/consts/const-eval/union-const-eval-field.stderr
+++ b/src/test/ui/consts/const-eval/union-const-eval-field.stderr
@@ -1,16 +1,11 @@
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/union-const-eval-field.rs:28:5
+error[E0080]: evaluation of constant value failed
+  --> $DIR/union-const-eval-field.rs:28:37
    |
 LL |     const FIELD3: Field3 = unsafe { UNION.field3 };
-   |     ^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered uninitialized bytes, but expected initialized bytes
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 8, align: 8) {
-               __ __ __ __ __ __ __ __                         │ ░░░░░░░░
-           }
+   |                                     ^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error[E0080]: erroneous constant used
-  --> $DIR/union-const-eval-field.rs:30:5
+  --> $DIR/union-const-eval-field.rs:31:5
    |
 LL |     FIELD3
    |     ^^^^^^ referenced constant has errors
diff --git a/src/test/ui/consts/const-eval/union-ice.rs b/src/test/ui/consts/const-eval/union-ice.rs
index 4189619b2..dd970a355 100644
--- a/src/test/ui/consts/const-eval/union-ice.rs
+++ b/src/test/ui/consts/const-eval/union-ice.rs
@@ -11,11 +11,15 @@ union DummyUnion {
 
 const UNION: DummyUnion = DummyUnion { field1: 1065353216 };
 
-const FIELD3: Field3 = unsafe { UNION.field3 }; //~ ERROR it is undefined behavior to use this value
+const FIELD3: Field3 = unsafe { UNION.field3 };
+//~^ ERROR evaluation of constant value failed
+//~| uninitialized
 
-const FIELD_PATH: Struct = Struct { //~ ERROR it is undefined behavior to use this value
+const FIELD_PATH: Struct = Struct {
     a: 42,
     b: unsafe { UNION.field3 },
+    //~^ ERROR evaluation of constant value failed
+    //~| uninitialized
 };
 
 struct Struct {
@@ -23,10 +27,12 @@ struct Struct {
     b: Field3,
 }
 
-const FIELD_PATH2: Struct2 = Struct2 { //~ ERROR it is undefined behavior to use this value
+const FIELD_PATH2: Struct2 = Struct2 {
     b: [
         21,
         unsafe { UNION.field3 },
+        //~^ ERROR evaluation of constant value failed
+        //~| uninitialized
         23,
         24,
     ],
diff --git a/src/test/ui/consts/const-eval/union-ice.stderr b/src/test/ui/consts/const-eval/union-ice.stderr
index 21a545509..bd39a0551 100644
--- a/src/test/ui/consts/const-eval/union-ice.stderr
+++ b/src/test/ui/consts/const-eval/union-ice.stderr
@@ -1,37 +1,20 @@
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/union-ice.rs:14:1
+error[E0080]: evaluation of constant value failed
+  --> $DIR/union-ice.rs:14:33
    |
 LL | const FIELD3: Field3 = unsafe { UNION.field3 };
-   | ^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered uninitialized bytes, but expected initialized bytes
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 8, align: 8) {
-               __ __ __ __ __ __ __ __                         │ ░░░░░░░░
-           }
+   |                                 ^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/union-ice.rs:16:1
-   |
-LL | const FIELD_PATH: Struct = Struct {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .b: encountered uninitialized bytes, but expected initialized bytes
+error[E0080]: evaluation of constant value failed
+  --> $DIR/union-ice.rs:20:17
    |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 16, align: 8) {
-               __ __ __ __ __ __ __ __ 2a __ __ __ __ __ __ __ │ ░░░░░░░░*░░░░░░░
-           }
+LL |     b: unsafe { UNION.field3 },
+   |                 ^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/union-ice.rs:26:1
-   |
-LL | const FIELD_PATH2: Struct2 = Struct2 {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .b[1]: encountered uninitialized bytes
+error[E0080]: evaluation of constant value failed
+  --> $DIR/union-ice.rs:33:18
    |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 40, align: 8) {
-               0x00 │ 15 00 00 00 00 00 00 00 __ __ __ __ __ __ __ __ │ ........░░░░░░░░
-               0x10 │ 17 00 00 00 00 00 00 00 18 00 00 00 00 00 00 00 │ ................
-               0x20 │ 2a __ __ __ __ __ __ __                         │ *░░░░░░░
-           }
+LL |         unsafe { UNION.field3 },
+   |                  ^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/consts/const-eval/union-ub.32bit.stderr b/src/test/ui/consts/const-eval/union-ub.32bit.stderr
index baf682596..38ded4d65 100644
--- a/src/test/ui/consts/const-eval/union-ub.32bit.stderr
+++ b/src/test/ui/consts/const-eval/union-ub.32bit.stderr
@@ -9,16 +9,11 @@ LL | const BAD_BOOL: bool = unsafe { DummyUnion { u8: 42 }.bool};
                2a                                              │ *
            }
 
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/union-ub.rs:35:1
+error[E0080]: evaluation of constant value failed
+  --> $DIR/union-ub.rs:35:36
    |
 LL | const UNINIT_BOOL: bool = unsafe { DummyUnion { unit: () }.bool};
-   | ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered uninitialized bytes, but expected a boolean
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 1, align: 1) {
-               __                                              │ ░
-           }
+   |                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/consts/const-eval/union-ub.64bit.stderr b/src/test/ui/consts/const-eval/union-ub.64bit.stderr
index baf682596..38ded4d65 100644
--- a/src/test/ui/consts/const-eval/union-ub.64bit.stderr
+++ b/src/test/ui/consts/const-eval/union-ub.64bit.stderr
@@ -9,16 +9,11 @@ LL | const BAD_BOOL: bool = unsafe { DummyUnion { u8: 42 }.bool};
                2a                                              │ *
            }
 
-error[E0080]: it is undefined behavior to use this value
-  --> $DIR/union-ub.rs:35:1
+error[E0080]: evaluation of constant value failed
+  --> $DIR/union-ub.rs:35:36
    |
 LL | const UNINIT_BOOL: bool = unsafe { DummyUnion { unit: () }.bool};
-   | ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered uninitialized bytes, but expected a boolean
-   |
-   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
-   = note: the raw bytes of the constant (size: 1, align: 1) {
-               __                                              │ ░
-           }
+   |                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/consts/const-eval/union-ub.rs b/src/test/ui/consts/const-eval/union-ub.rs
index c1bfe69a7..bb29edcf8 100644
--- a/src/test/ui/consts/const-eval/union-ub.rs
+++ b/src/test/ui/consts/const-eval/union-ub.rs
@@ -33,7 +33,8 @@ union Bar {
 const BAD_BOOL: bool = unsafe { DummyUnion { u8: 42 }.bool};
 //~^ ERROR it is undefined behavior to use this value
 const UNINIT_BOOL: bool = unsafe { DummyUnion { unit: () }.bool};
-//~^ ERROR it is undefined behavior to use this value
+//~^ ERROR evaluation of constant value failed
+//~| uninitialized
 
 // The value is not valid for any union variant, but that's fine
 // unions are just a convenient way to transmute bits around
diff --git a/src/test/ui/consts/const-float-bits-reject-conv.stderr b/src/test/ui/consts/const-float-bits-reject-conv.stderr
index d6e993a10..01f2f4895 100644
--- a/src/test/ui/consts/const-float-bits-reject-conv.stderr
+++ b/src/test/ui/consts/const-float-bits-reject-conv.stderr
@@ -10,16 +10,6 @@ LL |                     panic!("const-eval error: cannot use f32::to_bits on a
 LL |         unsafe { intrinsics::const_eval_select((self,), ct_f32_to_u32, rt_f32_to_u32) }
    |                  -------------------------------------------------------------------- inside `core::f32::<impl f32>::to_bits` at $SRC_DIR/core/src/num/f32.rs:LL:COL
    |
-  ::: $SRC_DIR/core/src/ops/function.rs:LL:COL
-   |
-LL |     extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
-   |     ------------------------------------------------------------------ inside `<fn(f32) -> u32 {core::f32::<impl f32>::to_bits::ct_f32_to_u32} as FnOnce<(f32,)>>::call_once - shim(fn(f32) -> u32 {core::f32::<impl f32>::to_bits::ct_f32_to_u32})` at $SRC_DIR/core/src/ops/function.rs:LL:COL
-   |
-  ::: $SRC_DIR/core/src/intrinsics.rs:LL:COL
-   |
-LL |     called_in_const.call_once(arg)
-   |     ------------------------------ inside `const_eval_select::<(f32,), fn(f32) -> u32 {core::f32::<impl f32>::to_bits::ct_f32_to_u32}, [closure@core::f32::<impl f32>::to_bits::{closure#0}], u32>` at $SRC_DIR/core/src/intrinsics.rs:LL:COL
-   |
   ::: $DIR/const-float-bits-reject-conv.rs:27:30
    |
 LL |     const MASKED_NAN1: u32 = f32::NAN.to_bits() ^ 0x002A_AAAA;
@@ -39,16 +29,6 @@ LL |                     panic!("const-eval error: cannot use f32::to_bits on a
 LL |         unsafe { intrinsics::const_eval_select((self,), ct_f32_to_u32, rt_f32_to_u32) }
    |                  -------------------------------------------------------------------- inside `core::f32::<impl f32>::to_bits` at $SRC_DIR/core/src/num/f32.rs:LL:COL
    |
-  ::: $SRC_DIR/core/src/ops/function.rs:LL:COL
-   |
-LL |     extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
-   |     ------------------------------------------------------------------ inside `<fn(f32) -> u32 {core::f32::<impl f32>::to_bits::ct_f32_to_u32} as FnOnce<(f32,)>>::call_once - shim(fn(f32) -> u32 {core::f32::<impl f32>::to_bits::ct_f32_to_u32})` at $SRC_DIR/core/src/ops/function.rs:LL:COL
-   |
-  ::: $SRC_DIR/core/src/intrinsics.rs:LL:COL
-   |
-LL |     called_in_const.call_once(arg)
-   |     ------------------------------ inside `const_eval_select::<(f32,), fn(f32) -> u32 {core::f32::<impl f32>::to_bits::ct_f32_to_u32}, [closure@core::f32::<impl f32>::to_bits::{closure#0}], u32>` at $SRC_DIR/core/src/intrinsics.rs:LL:COL
-   |
   ::: $DIR/const-float-bits-reject-conv.rs:28:30
    |
 LL |     const MASKED_NAN2: u32 = f32::NAN.to_bits() ^ 0x0055_5555;
@@ -117,16 +97,6 @@ LL |                     panic!("const-eval error: cannot use f64::to_bits on a
 LL |         unsafe { intrinsics::const_eval_select((self,), ct_f64_to_u64, rt_f64_to_u64) }
    |                  -------------------------------------------------------------------- inside `core::f64::<impl f64>::to_bits` at $SRC_DIR/core/src/num/f64.rs:LL:COL
    |
-  ::: $SRC_DIR/core/src/ops/function.rs:LL:COL
-   |
-LL |     extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
-   |     ------------------------------------------------------------------ inside `<fn(f64) -> u64 {core::f64::<impl f64>::to_bits::ct_f64_to_u64} as FnOnce<(f64,)>>::call_once - shim(fn(f64) -> u64 {core::f64::<impl f64>::to_bits::ct_f64_to_u64})` at $SRC_DIR/core/src/ops/function.rs:LL:COL
-   |
-  ::: $SRC_DIR/core/src/intrinsics.rs:LL:COL
-   |
-LL |     called_in_const.call_once(arg)
-   |     ------------------------------ inside `const_eval_select::<(f64,), fn(f64) -> u64 {core::f64::<impl f64>::to_bits::ct_f64_to_u64}, [closure@core::f64::<impl f64>::to_bits::{closure#0}], u64>` at $SRC_DIR/core/src/intrinsics.rs:LL:COL
-   |
   ::: $DIR/const-float-bits-reject-conv.rs:54:30
    |
 LL |     const MASKED_NAN1: u64 = f64::NAN.to_bits() ^ 0x000A_AAAA_AAAA_AAAA;
@@ -146,16 +116,6 @@ LL |                     panic!("const-eval error: cannot use f64::to_bits on a
 LL |         unsafe { intrinsics::const_eval_select((self,), ct_f64_to_u64, rt_f64_to_u64) }
    |                  -------------------------------------------------------------------- inside `core::f64::<impl f64>::to_bits` at $SRC_DIR/core/src/num/f64.rs:LL:COL
    |
-  ::: $SRC_DIR/core/src/ops/function.rs:LL:COL
-   |
-LL |     extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
-   |     ------------------------------------------------------------------ inside `<fn(f64) -> u64 {core::f64::<impl f64>::to_bits::ct_f64_to_u64} as FnOnce<(f64,)>>::call_once - shim(fn(f64) -> u64 {core::f64::<impl f64>::to_bits::ct_f64_to_u64})` at $SRC_DIR/core/src/ops/function.rs:LL:COL
-   |
-  ::: $SRC_DIR/core/src/intrinsics.rs:LL:COL
-   |
-LL |     called_in_const.call_once(arg)
-   |     ------------------------------ inside `const_eval_select::<(f64,), fn(f64) -> u64 {core::f64::<impl f64>::to_bits::ct_f64_to_u64}, [closure@core::f64::<impl f64>::to_bits::{closure#0}], u64>` at $SRC_DIR/core/src/intrinsics.rs:LL:COL
-   |
   ::: $DIR/const-float-bits-reject-conv.rs:55:30
    |
 LL |     const MASKED_NAN2: u64 = f64::NAN.to_bits() ^ 0x0005_5555_5555_5555;
diff --git a/src/test/ui/consts/const-points-to-static.32bit.stderr b/src/test/ui/consts/const-points-to-static.32bit.stderr
index 97825dd0e..c7a435a1e 100644
--- a/src/test/ui/consts/const-points-to-static.32bit.stderr
+++ b/src/test/ui/consts/const-points-to-static.32bit.stderr
@@ -2,7 +2,7 @@ error[E0080]: it is undefined behavior to use this value
   --> $DIR/const-points-to-static.rs:6:1
    |
 LL | const TEST: &u8 = &MY_STATIC;
-   | ^^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to a static variable
+   | ^^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to a static variable in a constant
    |
    = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
    = note: the raw bytes of the constant (size: 4, align: 4) {
diff --git a/src/test/ui/consts/const-points-to-static.64bit.stderr b/src/test/ui/consts/const-points-to-static.64bit.stderr
index 0d4a5a8ce..4d5b8eac5 100644
--- a/src/test/ui/consts/const-points-to-static.64bit.stderr
+++ b/src/test/ui/consts/const-points-to-static.64bit.stderr
@@ -2,7 +2,7 @@ error[E0080]: it is undefined behavior to use this value
   --> $DIR/const-points-to-static.rs:6:1
    |
 LL | const TEST: &u8 = &MY_STATIC;
-   | ^^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to a static variable
+   | ^^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to a static variable in a constant
    |
    = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
    = note: the raw bytes of the constant (size: 8, align: 8) {
diff --git a/src/test/ui/consts/const_in_pattern/incomplete-slice.rs b/src/test/ui/consts/const_in_pattern/incomplete-slice.rs
new file mode 100644
index 000000000..e1ccda71d
--- /dev/null
+++ b/src/test/ui/consts/const_in_pattern/incomplete-slice.rs
@@ -0,0 +1,15 @@
+#[derive(PartialEq)]
+enum E {
+    A,
+}
+
+const E_SL: &[E] = &[E::A];
+
+fn main() {
+    match &[][..] {
+        //~^ ERROR non-exhaustive patterns: `&_` not covered [E0004]
+        E_SL => {}
+        //~^ WARN to use a constant of type `E` in a pattern, `E` must be annotated with `#[derive(PartialEq, Eq)]`
+        //~| WARN this was previously accepted by the compiler but is being phased out
+    }
+}
diff --git a/src/test/ui/consts/const_in_pattern/incomplete-slice.stderr b/src/test/ui/consts/const_in_pattern/incomplete-slice.stderr
new file mode 100644
index 000000000..0ff708371
--- /dev/null
+++ b/src/test/ui/consts/const_in_pattern/incomplete-slice.stderr
@@ -0,0 +1,26 @@
+warning: to use a constant of type `E` in a pattern, `E` must be annotated with `#[derive(PartialEq, Eq)]`
+  --> $DIR/incomplete-slice.rs:11:9
+   |
+LL |         E_SL => {}
+   |         ^^^^
+   |
+   = note: `#[warn(indirect_structural_match)]` on by default
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #62411 <https://github.com/rust-lang/rust/issues/62411>
+
+error[E0004]: non-exhaustive patterns: `&_` not covered
+  --> $DIR/incomplete-slice.rs:9:11
+   |
+LL |     match &[][..] {
+   |           ^^^^^^^ pattern `&_` not covered
+   |
+   = note: the matched value is of type `&[E]`
+help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
+   |
+LL ~         E_SL => {}
+LL +         &_ => todo!()
+   |
+
+error: aborting due to previous error; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0004`.
diff --git a/src/test/ui/consts/extra-const-ub/detect-extra-ub.rs b/src/test/ui/consts/extra-const-ub/detect-extra-ub.rs
new file mode 100644
index 000000000..86fbadb94
--- /dev/null
+++ b/src/test/ui/consts/extra-const-ub/detect-extra-ub.rs
@@ -0,0 +1,45 @@
+// revisions: no_flag with_flag
+// [no_flag] check-pass
+// [with_flag] compile-flags: -Zextra-const-ub-checks
+#![feature(const_ptr_read)]
+
+use std::mem::transmute;
+
+const INVALID_BOOL: () = unsafe {
+    let _x: bool = transmute(3u8);
+    //[with_flag]~^ ERROR: evaluation of constant value failed
+    //[with_flag]~| invalid value
+};
+
+const INVALID_PTR_IN_INT: () = unsafe {
+    let _x: usize = transmute(&3u8);
+    //[with_flag]~^ ERROR: any use of this value will cause an error
+    //[with_flag]~| previously accepted
+};
+
+const INVALID_SLICE_TO_USIZE_TRANSMUTE: () = unsafe {
+    let x: &[u8] = &[0; 32];
+    let _x: (usize, usize) = transmute(x);
+    //[with_flag]~^ ERROR: any use of this value will cause an error
+    //[with_flag]~| previously accepted
+};
+
+const UNALIGNED_PTR: () = unsafe {
+    let _x: &u32 = transmute(&[0u8; 4]);
+    //[with_flag]~^ ERROR: evaluation of constant value failed
+    //[with_flag]~| invalid value
+};
+
+const UNALIGNED_READ: () = {
+    INNER; //[with_flag]~ERROR any use of this value will cause an error
+    //[with_flag]~| previously accepted
+    // There is an error here but its span is in the standard library so we cannot match it...
+    // so we have this in a *nested* const, such that the *outer* const fails to use it.
+    const INNER: () = unsafe {
+        let x = &[0u8; 4];
+        let ptr = x.as_ptr().cast::<u32>();
+        ptr.read();
+    };
+};
+
+fn main() {}
diff --git a/src/test/ui/consts/extra-const-ub/detect-extra-ub.with_flag.stderr b/src/test/ui/consts/extra-const-ub/detect-extra-ub.with_flag.stderr
new file mode 100644
index 000000000..793725d3b
--- /dev/null
+++ b/src/test/ui/consts/extra-const-ub/detect-extra-ub.with_flag.stderr
@@ -0,0 +1,117 @@
+error[E0080]: evaluation of constant value failed
+  --> $DIR/detect-extra-ub.rs:9:20
+   |
+LL |     let _x: bool = transmute(3u8);
+   |                    ^^^^^^^^^^^^^^ constructing invalid value: encountered 0x03, but expected a boolean
+
+error: any use of this value will cause an error
+  --> $DIR/detect-extra-ub.rs:15:21
+   |
+LL | const INVALID_PTR_IN_INT: () = unsafe {
+   | ----------------------------
+LL |     let _x: usize = transmute(&3u8);
+   |                     ^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
+   |
+   = note: `#[deny(const_err)]` on by default
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
+   = help: this code performed an operation that depends on the underlying bytes representing a pointer
+   = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
+
+error: any use of this value will cause an error
+  --> $DIR/detect-extra-ub.rs:22:30
+   |
+LL | const INVALID_SLICE_TO_USIZE_TRANSMUTE: () = unsafe {
+   | ------------------------------------------
+LL |     let x: &[u8] = &[0; 32];
+LL |     let _x: (usize, usize) = transmute(x);
+   |                              ^^^^^^^^^^^^ unable to turn pointer into raw bytes
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
+   = help: this code performed an operation that depends on the underlying bytes representing a pointer
+   = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
+
+error[E0080]: evaluation of constant value failed
+  --> $DIR/detect-extra-ub.rs:28:20
+   |
+LL |     let _x: &u32 = transmute(&[0u8; 4]);
+   |                    ^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered an unaligned reference (required 4 byte alignment but found 1)
+
+error[E0080]: evaluation of constant value failed
+  --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
+   |
+LL |         copy_nonoverlapping(src, tmp.as_mut_ptr(), 1);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |         |
+   |         accessing memory with alignment 1, but alignment 4 is required
+   |         inside `std::ptr::read::<u32>` at $SRC_DIR/core/src/ptr/mod.rs:LL:COL
+   |
+  ::: $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
+   |
+LL |         unsafe { read(self) }
+   |                  ---------- inside `ptr::const_ptr::<impl *const u32>::read` at $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
+   |
+  ::: $DIR/detect-extra-ub.rs:41:9
+   |
+LL |         ptr.read();
+   |         ---------- inside `INNER` at $DIR/detect-extra-ub.rs:41:9
+
+error: any use of this value will cause an error
+  --> $DIR/detect-extra-ub.rs:34:5
+   |
+LL | const UNALIGNED_READ: () = {
+   | ------------------------
+LL |     INNER;
+   |     ^^^^^ referenced constant has errors
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
+
+error: aborting due to 6 previous errors
+
+For more information about this error, try `rustc --explain E0080`.
+Future incompatibility report: Future breakage diagnostic:
+error: any use of this value will cause an error
+  --> $DIR/detect-extra-ub.rs:15:21
+   |
+LL | const INVALID_PTR_IN_INT: () = unsafe {
+   | ----------------------------
+LL |     let _x: usize = transmute(&3u8);
+   |                     ^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
+   |
+   = note: `#[deny(const_err)]` on by default
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
+   = help: this code performed an operation that depends on the underlying bytes representing a pointer
+   = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
+
+Future breakage diagnostic:
+error: any use of this value will cause an error
+  --> $DIR/detect-extra-ub.rs:22:30
+   |
+LL | const INVALID_SLICE_TO_USIZE_TRANSMUTE: () = unsafe {
+   | ------------------------------------------
+LL |     let x: &[u8] = &[0; 32];
+LL |     let _x: (usize, usize) = transmute(x);
+   |                              ^^^^^^^^^^^^ unable to turn pointer into raw bytes
+   |
+   = note: `#[deny(const_err)]` on by default
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
+   = help: this code performed an operation that depends on the underlying bytes representing a pointer
+   = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
+
+Future breakage diagnostic:
+error: any use of this value will cause an error
+  --> $DIR/detect-extra-ub.rs:34:5
+   |
+LL | const UNALIGNED_READ: () = {
+   | ------------------------
+LL |     INNER;
+   |     ^^^^^ referenced constant has errors
+   |
+   = note: `#[deny(const_err)]` on by default
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
+
diff --git a/src/test/ui/consts/extra-const-ub/issue-100771.rs b/src/test/ui/consts/extra-const-ub/issue-100771.rs
new file mode 100644
index 000000000..a32960328
--- /dev/null
+++ b/src/test/ui/consts/extra-const-ub/issue-100771.rs
@@ -0,0 +1,20 @@
+// check-pass
+// compile-flags: -Zextra-const-ub-checks
+
+#[derive(PartialEq, Eq, Copy, Clone)]
+#[repr(packed)]
+struct Foo {
+    field: (i64, u32, u32, u32),
+}
+
+const FOO: Foo = Foo {
+    field: (5, 6, 7, 8),
+};
+
+fn main() {
+    match FOO {
+        Foo { field: (5, 6, 7, 8) } => {},
+        FOO => unreachable!(),
+        _ => unreachable!(),
+    }
+}
diff --git a/src/test/ui/consts/extra-const-ub/issue-101034.rs b/src/test/ui/consts/extra-const-ub/issue-101034.rs
new file mode 100644
index 000000000..e0de705c4
--- /dev/null
+++ b/src/test/ui/consts/extra-const-ub/issue-101034.rs
@@ -0,0 +1,17 @@
+// check-pass
+// compile-flags: -Zextra-const-ub-checks
+
+#[repr(packed)]
+pub struct Foo {
+    bar: u8,
+    baa: [u32; 1],
+}
+
+const FOOMP: Foo = Foo {
+    bar: 0,
+    baa: [69; 1],
+};
+
+fn main() {
+    let _val = FOOMP;
+}
diff --git a/src/test/ui/consts/issue-32829-2.stderr b/src/test/ui/consts/issue-32829-2.stderr
index b94bdc0e3..0fec35818 100644
--- a/src/test/ui/consts/issue-32829-2.stderr
+++ b/src/test/ui/consts/issue-32829-2.stderr
@@ -13,6 +13,7 @@ LL |         invalid();
    |         ^^^^^^^^^
    |
    = note: calls in statics are limited to constant functions, tuple structs and tuple variants
+   = note: consider wrapping this expression in `Lazy::new(|| ...)` from the `once_cell` crate: https://crates.io/crates/once_cell
 
 error[E0015]: cannot call non-const fn `invalid` in statics
   --> $DIR/issue-32829-2.rs:54:9
@@ -21,6 +22,7 @@ LL |         invalid();
    |         ^^^^^^^^^
    |
    = note: calls in statics are limited to constant functions, tuple structs and tuple variants
+   = note: consider wrapping this expression in `Lazy::new(|| ...)` from the `once_cell` crate: https://crates.io/crates/once_cell
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/consts/issue-36163.stderr b/src/test/ui/consts/issue-36163.stderr
index 4797d10b7..9ac6c984c 100644
--- a/src/test/ui/consts/issue-36163.stderr
+++ b/src/test/ui/consts/issue-36163.stderr
@@ -8,7 +8,7 @@ note: ...which requires const-evaluating + checking `A`...
   --> $DIR/issue-36163.rs:1:1
    |
 LL | const A: isize = Foo::B as isize;
-   | ^^^^^^^^^^^^^^
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: ...which again requires const-evaluating + checking `Foo::B::{constant#0}`, completing the cycle
 note: cycle used when simplifying constant for the type system `Foo::B::{constant#0}`
   --> $DIR/issue-36163.rs:4:9
diff --git a/src/test/ui/consts/issue-miri-1910.rs b/src/test/ui/consts/issue-miri-1910.rs
index 2b23626e3..29e0ea950 100644
--- a/src/test/ui/consts/issue-miri-1910.rs
+++ b/src/test/ui/consts/issue-miri-1910.rs
@@ -1,4 +1,5 @@
 // error-pattern unable to turn pointer into raw bytes
+// normalize-stderr-test: "alloc[0-9]+\+0x[a-z0-9]+" -> "ALLOC"
 #![feature(const_ptr_read)]
 
 const C: () = unsafe {
diff --git a/src/test/ui/consts/issue-miri-1910.stderr b/src/test/ui/consts/issue-miri-1910.stderr
index d953c7819..0f0539e09 100644
--- a/src/test/ui/consts/issue-miri-1910.stderr
+++ b/src/test/ui/consts/issue-miri-1910.stderr
@@ -4,12 +4,12 @@ error: any use of this value will cause an error
 LL |         copy_nonoverlapping(src, tmp.as_mut_ptr(), 1);
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |         |
-   |         unable to turn pointer into raw bytes
+   |         unable to copy parts of a pointer from memory at ALLOC
    |         inside `std::ptr::read::<u8>` at $SRC_DIR/core/src/ptr/mod.rs:LL:COL
    |         inside `ptr::const_ptr::<impl *const u8>::read` at $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
-   |         inside `C` at $DIR/issue-miri-1910.rs:7:5
+   |         inside `C` at $DIR/issue-miri-1910.rs:8:5
    |
-  ::: $DIR/issue-miri-1910.rs:4:1
+  ::: $DIR/issue-miri-1910.rs:5:1
    |
 LL | const C: () = unsafe {
    | -----------
@@ -29,12 +29,12 @@ error: any use of this value will cause an error
 LL |         copy_nonoverlapping(src, tmp.as_mut_ptr(), 1);
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |         |
-   |         unable to turn pointer into raw bytes
+   |         unable to copy parts of a pointer from memory at ALLOC
    |         inside `std::ptr::read::<u8>` at $SRC_DIR/core/src/ptr/mod.rs:LL:COL
    |         inside `ptr::const_ptr::<impl *const u8>::read` at $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
-   |         inside `C` at $DIR/issue-miri-1910.rs:7:5
+   |         inside `C` at $DIR/issue-miri-1910.rs:8:5
    |
-  ::: $DIR/issue-miri-1910.rs:4:1
+  ::: $DIR/issue-miri-1910.rs:5:1
    |
 LL | const C: () = unsafe {
    | -----------
diff --git a/src/test/ui/consts/mir_check_nonconst.stderr b/src/test/ui/consts/mir_check_nonconst.stderr
index 2bac995ee..1e0652722 100644
--- a/src/test/ui/consts/mir_check_nonconst.stderr
+++ b/src/test/ui/consts/mir_check_nonconst.stderr
@@ -5,6 +5,7 @@ LL | static foo: Foo = bar();
    |                   ^^^^^
    |
    = note: calls in statics are limited to constant functions, tuple structs and tuple variants
+   = note: consider wrapping this expression in `Lazy::new(|| ...)` from the `once_cell` crate: https://crates.io/crates/once_cell
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/consts/miri_unleashed/const_refers_to_static2.32bit.stderr b/src/test/ui/consts/miri_unleashed/const_refers_to_static2.32bit.stderr
index b3ad81e49..14173ac9f 100644
--- a/src/test/ui/consts/miri_unleashed/const_refers_to_static2.32bit.stderr
+++ b/src/test/ui/consts/miri_unleashed/const_refers_to_static2.32bit.stderr
@@ -2,7 +2,7 @@ error[E0080]: it is undefined behavior to use this value
   --> $DIR/const_refers_to_static2.rs:11:1
    |
 LL | const REF_INTERIOR_MUT: &usize = {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to a static variable
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to a static variable in a constant
    |
    = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
    = note: the raw bytes of the constant (size: 4, align: 4) {
@@ -13,7 +13,7 @@ error[E0080]: it is undefined behavior to use this value
   --> $DIR/const_refers_to_static2.rs:18:1
    |
 LL | const READ_IMMUT: &usize = {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to a static variable
+   | ^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to a static variable in a constant
    |
    = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
    = note: the raw bytes of the constant (size: 4, align: 4) {
diff --git a/src/test/ui/consts/miri_unleashed/const_refers_to_static2.64bit.stderr b/src/test/ui/consts/miri_unleashed/const_refers_to_static2.64bit.stderr
index 24bd07092..e7e51a418 100644
--- a/src/test/ui/consts/miri_unleashed/const_refers_to_static2.64bit.stderr
+++ b/src/test/ui/consts/miri_unleashed/const_refers_to_static2.64bit.stderr
@@ -2,7 +2,7 @@ error[E0080]: it is undefined behavior to use this value
   --> $DIR/const_refers_to_static2.rs:11:1
    |
 LL | const REF_INTERIOR_MUT: &usize = {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to a static variable
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to a static variable in a constant
    |
    = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
    = note: the raw bytes of the constant (size: 8, align: 8) {
@@ -13,7 +13,7 @@ error[E0080]: it is undefined behavior to use this value
   --> $DIR/const_refers_to_static2.rs:18:1
    |
 LL | const READ_IMMUT: &usize = {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to a static variable
+   | ^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to a static variable in a constant
    |
    = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
    = note: the raw bytes of the constant (size: 8, align: 8) {
diff --git a/src/test/ui/consts/miri_unleashed/const_refers_to_static_cross_crate.32bit.stderr b/src/test/ui/consts/miri_unleashed/const_refers_to_static_cross_crate.32bit.stderr
index 20a96b57f..3a22b0689 100644
--- a/src/test/ui/consts/miri_unleashed/const_refers_to_static_cross_crate.32bit.stderr
+++ b/src/test/ui/consts/miri_unleashed/const_refers_to_static_cross_crate.32bit.stderr
@@ -2,7 +2,7 @@ error[E0080]: it is undefined behavior to use this value
   --> $DIR/const_refers_to_static_cross_crate.rs:12:1
    |
 LL | const SLICE_MUT: &[u8; 1] = {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to a static variable
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to a static variable in a constant
    |
    = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
    = note: the raw bytes of the constant (size: 4, align: 4) {
@@ -19,7 +19,7 @@ error[E0080]: it is undefined behavior to use this value
   --> $DIR/const_refers_to_static_cross_crate.rs:17:1
    |
 LL | const U8_MUT: &u8 = {
-   | ^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to a static variable
+   | ^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to a static variable in a constant
    |
    = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
    = note: the raw bytes of the constant (size: 4, align: 4) {
diff --git a/src/test/ui/consts/miri_unleashed/const_refers_to_static_cross_crate.64bit.stderr b/src/test/ui/consts/miri_unleashed/const_refers_to_static_cross_crate.64bit.stderr
index dfa0f76ba..39c874d64 100644
--- a/src/test/ui/consts/miri_unleashed/const_refers_to_static_cross_crate.64bit.stderr
+++ b/src/test/ui/consts/miri_unleashed/const_refers_to_static_cross_crate.64bit.stderr
@@ -2,7 +2,7 @@ error[E0080]: it is undefined behavior to use this value
   --> $DIR/const_refers_to_static_cross_crate.rs:12:1
    |
 LL | const SLICE_MUT: &[u8; 1] = {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to a static variable
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to a static variable in a constant
    |
    = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
    = note: the raw bytes of the constant (size: 8, align: 8) {
@@ -19,7 +19,7 @@ error[E0080]: it is undefined behavior to use this value
   --> $DIR/const_refers_to_static_cross_crate.rs:17:1
    |
 LL | const U8_MUT: &u8 = {
-   | ^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to a static variable
+   | ^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to a static variable in a constant
    |
    = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
    = note: the raw bytes of the constant (size: 8, align: 8) {
diff --git a/src/test/ui/consts/miri_unleashed/ptr_arith.rs b/src/test/ui/consts/miri_unleashed/ptr_arith.rs
index 13e6af36e..6a19b2945 100644
--- a/src/test/ui/consts/miri_unleashed/ptr_arith.rs
+++ b/src/test/ui/consts/miri_unleashed/ptr_arith.rs
@@ -8,7 +8,7 @@
 static PTR_INT_CAST: () = {
     let x = &0 as *const _ as usize;
     //~^ ERROR could not evaluate static initializer
-    //~| "exposing pointers" needs an rfc before being allowed inside constants
+    //~| exposing pointers
     let _v = x == x;
 };
 
@@ -19,4 +19,7 @@ static PTR_INT_TRANSMUTE: () = unsafe {
     //~| unable to turn pointer into raw bytes
 };
 
+// I'd love to test pointer comparison, but that is not possible since
+// their `PartialEq` impl is non-`const`.
+
 fn main() {}
diff --git a/src/test/ui/consts/miri_unleashed/ptr_arith.stderr b/src/test/ui/consts/miri_unleashed/ptr_arith.stderr
index f67ac4802..e0c4fa175 100644
--- a/src/test/ui/consts/miri_unleashed/ptr_arith.stderr
+++ b/src/test/ui/consts/miri_unleashed/ptr_arith.stderr
@@ -2,7 +2,7 @@ error[E0080]: could not evaluate static initializer
   --> $DIR/ptr_arith.rs:9:13
    |
 LL |     let x = &0 as *const _ as usize;
-   |             ^^^^^^^^^^^^^^^^^^^^^^^ "exposing pointers" needs an rfc before being allowed inside constants
+   |             ^^^^^^^^^^^^^^^^^^^^^^^ exposing pointers is not possible at compile-time
 
 error[E0080]: could not evaluate static initializer
   --> $DIR/ptr_arith.rs:17:14
diff --git a/src/test/ui/consts/miri_unleashed/slice_eq.rs b/src/test/ui/consts/miri_unleashed/slice_eq.rs
index fd843105d..83e10bf12 100644
--- a/src/test/ui/consts/miri_unleashed/slice_eq.rs
+++ b/src/test/ui/consts/miri_unleashed/slice_eq.rs
@@ -4,14 +4,10 @@
 #![feature(const_raw_ptr_comparison)]
 
 const EMPTY_SLICE: &[i32] = &[];
-const EMPTY_EQ: bool = EMPTY_SLICE.as_ptr().guaranteed_eq(&[] as *const _);
-const EMPTY_EQ2: bool = EMPTY_SLICE.as_ptr().guaranteed_ne(&[] as *const _);
-const EMPTY_NE: bool = EMPTY_SLICE.as_ptr().guaranteed_ne(&[1] as *const _);
-const EMPTY_NE2: bool = EMPTY_SLICE.as_ptr().guaranteed_eq(&[1] as *const _);
+const EMPTY_EQ: Option<bool> = EMPTY_SLICE.as_ptr().guaranteed_eq(&[] as *const _);
+const EMPTY_EQ2: Option<bool> = EMPTY_SLICE.as_ptr().guaranteed_eq(&[1] as *const _);
 
 fn main() {
-    assert!(!EMPTY_EQ);
-    assert!(!EMPTY_EQ2);
-    assert!(!EMPTY_NE);
-    assert!(!EMPTY_NE2);
+    assert!(EMPTY_EQ.is_none());
+    assert!(EMPTY_EQ2.is_none());
 }
diff --git a/src/test/ui/consts/offset.rs b/src/test/ui/consts/offset.rs
index f9ddda554..b2c663fe6 100644
--- a/src/test/ui/consts/offset.rs
+++ b/src/test/ui/consts/offset.rs
@@ -1,5 +1,4 @@
 // run-pass
-#![feature(const_ptr_offset_from)]
 use std::ptr;
 
 #[repr(C)]
diff --git a/src/test/ui/consts/offset_from.rs b/src/test/ui/consts/offset_from.rs
index b53718316..465147041 100644
--- a/src/test/ui/consts/offset_from.rs
+++ b/src/test/ui/consts/offset_from.rs
@@ -1,6 +1,5 @@
 // run-pass
 
-#![feature(const_ptr_offset_from)]
 #![feature(const_ptr_sub_ptr)]
 #![feature(ptr_sub_ptr)]
 
diff --git a/src/test/ui/consts/offset_from_ub.rs b/src/test/ui/consts/offset_from_ub.rs
index 1f29a6905..51163e650 100644
--- a/src/test/ui/consts/offset_from_ub.rs
+++ b/src/test/ui/consts/offset_from_ub.rs
@@ -1,4 +1,4 @@
-#![feature(const_ptr_offset_from)]
+#![feature(const_ptr_sub_ptr)]
 #![feature(core_intrinsics)]
 
 use std::intrinsics::{ptr_offset_from, ptr_offset_from_unsigned};
diff --git a/src/test/ui/consts/ptr_comparisons.rs b/src/test/ui/consts/ptr_comparisons.rs
index 20233db09..0a3c2d4be 100644
--- a/src/test/ui/consts/ptr_comparisons.rs
+++ b/src/test/ui/consts/ptr_comparisons.rs
@@ -14,38 +14,30 @@ const FOO: &usize = &42;
 macro_rules! check {
     (eq, $a:expr, $b:expr) => {
         pub const _: () =
-            assert!(std::intrinsics::ptr_guaranteed_eq($a as *const u8, $b as *const u8));
+            assert!(std::intrinsics::ptr_guaranteed_cmp($a as *const u8, $b as *const u8) == 1);
     };
     (ne, $a:expr, $b:expr) => {
         pub const _: () =
-            assert!(std::intrinsics::ptr_guaranteed_ne($a as *const u8, $b as *const u8));
+            assert!(std::intrinsics::ptr_guaranteed_cmp($a as *const u8, $b as *const u8) == 0);
     };
-    (!eq, $a:expr, $b:expr) => {
+    (!, $a:expr, $b:expr) => {
         pub const _: () =
-            assert!(!std::intrinsics::ptr_guaranteed_eq($a as *const u8, $b as *const u8));
-    };
-    (!ne, $a:expr, $b:expr) => {
-        pub const _: () =
-            assert!(!std::intrinsics::ptr_guaranteed_ne($a as *const u8, $b as *const u8));
+            assert!(std::intrinsics::ptr_guaranteed_cmp($a as *const u8, $b as *const u8) == 2);
     };
 }
 
 check!(eq, 0, 0);
 check!(ne, 0, 1);
-check!(!eq, 0, 1);
-check!(!ne, 0, 0);
 check!(ne, FOO as *const _, 0);
-check!(!eq, FOO as *const _, 0);
+check!(ne, unsafe { (FOO as *const usize).offset(1) }, 0);
+check!(ne, unsafe { (FOO as *const usize as *const u8).offset(3) }, 0);
+
 // We want pointers to be equal to themselves, but aren't checking this yet because
 // there are some open questions (e.g. whether function pointers to the same function
 // compare equal, they don't necessarily at runtime).
 // The case tested here should work eventually, but does not work yet.
-check!(!eq, FOO as *const _, FOO as *const _);
-check!(ne, unsafe { (FOO as *const usize).offset(1) }, 0);
-check!(!eq, unsafe { (FOO as *const usize).offset(1) }, 0);
+check!(!, FOO as *const _, FOO as *const _);
 
-check!(ne, unsafe { (FOO as *const usize as *const u8).offset(3) }, 0);
-check!(!eq, unsafe { (FOO as *const usize as *const u8).offset(3) }, 0);
 
 ///////////////////////////////////////////////////////////////////////////////
 // If any of the below start compiling, make sure to add a `check` test for it.
diff --git a/src/test/ui/consts/ptr_comparisons.stderr b/src/test/ui/consts/ptr_comparisons.stderr
index 1d47f243f..3de2aba5b 100644
--- a/src/test/ui/consts/ptr_comparisons.stderr
+++ b/src/test/ui/consts/ptr_comparisons.stderr
@@ -7,19 +7,19 @@ LL |         unsafe { intrinsics::offset(self, count) }
    |                  out-of-bounds pointer arithmetic: alloc3 has size $WORD, so pointer to $TWO_WORDS bytes starting at offset 0 is out-of-bounds
    |                  inside `ptr::const_ptr::<impl *const usize>::offset` at $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
    |
-  ::: $DIR/ptr_comparisons.rs:58:34
+  ::: $DIR/ptr_comparisons.rs:50:34
    |
 LL | const _: *const usize = unsafe { (FOO as *const usize).offset(2) };
-   |                                  ------------------------------- inside `_` at $DIR/ptr_comparisons.rs:58:34
+   |                                  ------------------------------- inside `_` at $DIR/ptr_comparisons.rs:50:34
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ptr_comparisons.rs:61:33
+  --> $DIR/ptr_comparisons.rs:53:33
    |
 LL |     unsafe { std::ptr::addr_of!((*(FOO as *const usize as *const [u8; 1000]))[999]) };
    |                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ dereferencing pointer failed: alloc3 has size $WORD, so pointer to 1000 bytes starting at offset 0 is out-of-bounds
 
 error: any use of this value will cause an error
-  --> $DIR/ptr_comparisons.rs:65:27
+  --> $DIR/ptr_comparisons.rs:57:27
    |
 LL | const _: usize = unsafe { std::mem::transmute::<*const usize, usize>(FOO) + 4 };
    | --------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -31,7 +31,7 @@ LL | const _: usize = unsafe { std::mem::transmute::<*const usize, usize>(FOO) +
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: any use of this value will cause an error
-  --> $DIR/ptr_comparisons.rs:70:27
+  --> $DIR/ptr_comparisons.rs:62:27
    |
 LL | const _: usize = unsafe { *std::mem::transmute::<&&usize, &usize>(&FOO) + 4 };
    | --------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -46,7 +46,7 @@ error: aborting due to 4 previous errors
 For more information about this error, try `rustc --explain E0080`.
 Future incompatibility report: Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ptr_comparisons.rs:65:27
+  --> $DIR/ptr_comparisons.rs:57:27
    |
 LL | const _: usize = unsafe { std::mem::transmute::<*const usize, usize>(FOO) + 4 };
    | --------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -59,7 +59,7 @@ LL | const _: usize = unsafe { std::mem::transmute::<*const usize, usize>(FOO) +
 
 Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/ptr_comparisons.rs:70:27
+  --> $DIR/ptr_comparisons.rs:62:27
    |
 LL | const _: usize = unsafe { *std::mem::transmute::<&&usize, &usize>(&FOO) + 4 };
    | --------------            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
diff --git a/src/test/ui/consts/unnormalized-param-env.rs b/src/test/ui/consts/unnormalized-param-env.rs
new file mode 100644
index 000000000..a7bbe4db9
--- /dev/null
+++ b/src/test/ui/consts/unnormalized-param-env.rs
@@ -0,0 +1,31 @@
+// check-pass
+
+pub trait CSpace<const N: usize> {
+    type Traj;
+}
+
+pub struct Const<const R: usize>;
+
+pub trait Obstacle<CS, const N: usize> {
+    fn trajectory_free<FT, S1>(&self, t: &FT)
+    where
+        CS::Traj: Sized,
+        CS: CSpace<N>;
+}
+
+// -----
+
+const N: usize = 4;
+
+struct ObstacleSpace2df32;
+
+impl<CS> Obstacle<CS, N> for ObstacleSpace2df32 {
+    fn trajectory_free<TF, S1>(&self, t: &TF)
+    where
+        CS::Traj: Sized,
+        CS: CSpace<N>,
+    {
+    }
+}
+
+fn main() {}