diff --git a/rust-version b/rust-version
index 323af716826..1ab8e6b5a8c 100644
--- a/rust-version
+++ b/rust-version
@@ -1 +1 @@
-ddcbba036aee08f0709f98a92a342a278eae5c05
+bf45371f262e184b4a77adea88c8ac01ac79759b
diff --git a/tests/fail/branchless-select-i128-pointer.rs b/tests/fail/branchless-select-i128-pointer.rs
index 7e1b969e02c..a3b4021ba0c 100644
--- a/tests/fail/branchless-select-i128-pointer.rs
+++ b/tests/fail/branchless-select-i128-pointer.rs
@@ -12,7 +12,7 @@ fn main() {
         // However, it drops provenance when transmuting to TwoPtrs, so this is UB.
         let val = unsafe {
             transmute::<_, &str>(
-                //~^ ERROR type validation failed: encountered a dangling reference
+                //~^ ERROR constructing invalid value: encountered a dangling reference
                 !mask & transmute::<_, TwoPtrs>("false !")
                     | mask & transmute::<_, TwoPtrs>("true !"),
             )
diff --git a/tests/fail/branchless-select-i128-pointer.stderr b/tests/fail/branchless-select-i128-pointer.stderr
index 374d6ab0680..5cb05f33dde 100644
--- a/tests/fail/branchless-select-i128-pointer.stderr
+++ b/tests/fail/branchless-select-i128-pointer.stderr
@@ -1,4 +1,4 @@
-error: Undefined Behavior: type validation failed: encountered a dangling reference (address $HEX is unallocated)
+error: Undefined Behavior: constructing invalid value: encountered a dangling reference (address $HEX is unallocated)
   --> $DIR/branchless-select-i128-pointer.rs:LL:CC
    |
 LL | /             transmute::<_, &str>(
@@ -6,7 +6,7 @@ LL | |
 LL | |                 !mask & transmute::<_, TwoPtrs>("false !")
 LL | |                     | mask & transmute::<_, TwoPtrs>("true !"),
 LL | |             )
-   | |_____________^ type validation failed: encountered a dangling reference (address $HEX is unallocated)
+   | |_____________^ constructing invalid value: encountered a dangling reference (address $HEX is unallocated)
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/issue-miri-1112.stderr b/tests/fail/issue-miri-1112.stderr
index 1dfcad0c147..cf692bddaf4 100644
--- a/tests/fail/issue-miri-1112.stderr
+++ b/tests/fail/issue-miri-1112.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered invalid drop function pointer in vtable (function has incompatible signature)
+error: Undefined Behavior: constructing invalid value: encountered invalid drop function pointer in vtable (function has incompatible signature)
   --> $DIR/issue-miri-1112.rs:LL:CC
    |
 LL |         let obj = std::mem::transmute::<FatPointer, *mut FunnyPointer>(obj);
-   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered invalid drop function pointer in vtable (function has incompatible signature)
+   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered invalid drop function pointer in vtable (function has incompatible signature)
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/stacked_borrows/vtable.stderr b/tests/fail/stacked_borrows/vtable.stderr
index ac3d71045f0..31c3d5982e5 100644
--- a/tests/fail/stacked_borrows/vtable.stderr
+++ b/tests/fail/stacked_borrows/vtable.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered vtable pointer does not have permission to read drop function pointer
+error: Undefined Behavior: constructing invalid value: encountered vtable pointer does not have permission to read drop function pointer
   --> RUSTLIB/core/src/ptr/metadata.rs:LL:CC
    |
 LL |     unsafe { PtrRepr { components: PtrComponents { data_address, metadata } }.const_ptr }
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered vtable pointer does not have permission to read drop function pointer
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered vtable pointer does not have permission to read drop function pointer
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/transmute-pair-uninit.stderr b/tests/fail/transmute-pair-uninit.stderr
index 833c3abbb2f..c1f90c3efb6 100644
--- a/tests/fail/transmute-pair-uninit.stderr
+++ b/tests/fail/transmute-pair-uninit.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered uninitialized bytes, but expected initialized bytes
+error: Undefined Behavior: constructing invalid value: encountered uninitialized bytes, but expected initialized bytes
   --> $DIR/transmute-pair-uninit.rs:LL:CC
    |
 LL |     let v = unsafe { *z.offset(first_undef) };
-   |                      ^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered uninitialized bytes, but expected initialized bytes
+   |                      ^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered uninitialized bytes, but expected initialized bytes
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/transmute_fat1.rs b/tests/fail/transmute_fat1.rs
index 79286f3e27d..a60efb98f9d 100644
--- a/tests/fail/transmute_fat1.rs
+++ b/tests/fail/transmute_fat1.rs
@@ -7,7 +7,7 @@ const N: usize = 8;
 fn main() {
     let bad = unsafe {
         std::mem::transmute::<&[u8], [u8; N]>(&[1u8])
-        //~^ ERROR: type validation failed: encountered a pointer
+        //~^ ERROR: constructing invalid value: encountered a pointer
     };
     let _val = bad[0] + bad[bad.len() - 1];
 }
diff --git a/tests/fail/transmute_fat1.stderr b/tests/fail/transmute_fat1.stderr
index baf6195f92a..6263427bac5 100644
--- a/tests/fail/transmute_fat1.stderr
+++ b/tests/fail/transmute_fat1.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered a pointer, but expected plain (non-pointer) bytes
+error: Undefined Behavior: constructing invalid value: encountered a pointer, but expected plain (non-pointer) bytes
   --> $DIR/transmute_fat1.rs:LL:CC
    |
 LL |         std::mem::transmute::<&[u8], [u8; N]>(&[1u8])
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered a pointer, but expected plain (non-pointer) bytes
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a pointer, but expected plain (non-pointer) bytes
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/uninit_byte_read.stderr b/tests/fail/uninit_byte_read.stderr
index d150be3e7e7..d15b10dc6ed 100644
--- a/tests/fail/uninit_byte_read.stderr
+++ b/tests/fail/uninit_byte_read.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered uninitialized bytes, but expected initialized bytes
+error: Undefined Behavior: constructing invalid value: encountered uninitialized bytes, but expected initialized bytes
   --> $DIR/uninit_byte_read.rs:LL:CC
    |
 LL |     let undef = unsafe { *v.get_unchecked(5) };
-   |                          ^^^^^^^^^^^^^^^^^^^ type validation failed: encountered uninitialized bytes, but expected initialized bytes
+   |                          ^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered uninitialized bytes, but expected initialized bytes
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/uninit_raw_ptr.rs b/tests/fail/uninit_raw_ptr.rs
index beb9ad12709..c2ede1bb146 100644
--- a/tests/fail/uninit_raw_ptr.rs
+++ b/tests/fail/uninit_raw_ptr.rs
@@ -1,4 +1,4 @@
 fn main() {
     let _val = unsafe { std::mem::MaybeUninit::<*const u8>::uninit().assume_init() };
-    //~^ ERROR type validation failed at .value: encountered uninitialized raw pointer
+    //~^ ERROR constructing invalid value at .value: encountered uninitialized raw pointer
 }
diff --git a/tests/fail/uninit_raw_ptr.stderr b/tests/fail/uninit_raw_ptr.stderr
index 96074fc1e78..c76f59e13e7 100644
--- a/tests/fail/uninit_raw_ptr.stderr
+++ b/tests/fail/uninit_raw_ptr.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed at .value: encountered uninitialized raw pointer
+error: Undefined Behavior: constructing invalid value at .value: encountered uninitialized raw pointer
   --> $DIR/uninit_raw_ptr.rs:LL:CC
    |
 LL |     let _val = unsafe { std::mem::MaybeUninit::<*const u8>::uninit().assume_init() };
-   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed at .value: encountered uninitialized raw pointer
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .value: encountered uninitialized raw pointer
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/cast_fn_ptr1.stderr b/tests/fail/validity/cast_fn_ptr1.stderr
index d048377a779..05c75ac1338 100644
--- a/tests/fail/validity/cast_fn_ptr1.stderr
+++ b/tests/fail/validity/cast_fn_ptr1.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered a null reference
+error: Undefined Behavior: constructing invalid value: encountered a null reference
   --> $DIR/cast_fn_ptr1.rs:LL:CC
    |
 LL |     g(0usize as *const i32)
-   |     ^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered a null reference
+   |     ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a null reference
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/cast_fn_ptr2.stderr b/tests/fail/validity/cast_fn_ptr2.stderr
index 10b9b9b8602..8bee099caf3 100644
--- a/tests/fail/validity/cast_fn_ptr2.stderr
+++ b/tests/fail/validity/cast_fn_ptr2.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered a null reference
+error: Undefined Behavior: constructing invalid value: encountered a null reference
   --> $DIR/cast_fn_ptr2.rs:LL:CC
    |
 LL |     let _x = g();
-   |              ^^^ type validation failed: encountered a null reference
+   |              ^^^ constructing invalid value: encountered a null reference
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/dangling_ref1.stderr b/tests/fail/validity/dangling_ref1.stderr
index 0d358fd7f7f..290963c6d4e 100644
--- a/tests/fail/validity/dangling_ref1.stderr
+++ b/tests/fail/validity/dangling_ref1.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered a dangling reference (address 0x10 is unallocated)
+error: Undefined Behavior: constructing invalid value: encountered a dangling reference (address 0x10 is unallocated)
   --> $DIR/dangling_ref1.rs:LL:CC
    |
 LL |     let _x: &i32 = unsafe { mem::transmute(16usize) };
-   |                             ^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered a dangling reference (address 0x10 is unallocated)
+   |                             ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a dangling reference (address 0x10 is unallocated)
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/dangling_ref2.stderr b/tests/fail/validity/dangling_ref2.stderr
index e3bbb72fdcf..ce60f973ffe 100644
--- a/tests/fail/validity/dangling_ref2.stderr
+++ b/tests/fail/validity/dangling_ref2.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered a dangling reference (going beyond the bounds of its allocation)
+error: Undefined Behavior: constructing invalid value: encountered a dangling reference (going beyond the bounds of its allocation)
   --> $DIR/dangling_ref2.rs:LL:CC
    |
 LL |     let _x: &i32 = unsafe { mem::transmute(ptr) };
-   |                             ^^^^^^^^^^^^^^^^^^^ type validation failed: encountered a dangling reference (going beyond the bounds of its allocation)
+   |                             ^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a dangling reference (going beyond the bounds of its allocation)
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/dangling_ref3.stderr b/tests/fail/validity/dangling_ref3.stderr
index 5842eca9fc8..aa25f165608 100644
--- a/tests/fail/validity/dangling_ref3.stderr
+++ b/tests/fail/validity/dangling_ref3.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered a dangling reference (use-after-free)
+error: Undefined Behavior: constructing invalid value: encountered a dangling reference (use-after-free)
   --> $DIR/dangling_ref3.rs:LL:CC
    |
 LL |     let _x: &i32 = unsafe { mem::transmute(dangling()) };
-   |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered a dangling reference (use-after-free)
+   |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a dangling reference (use-after-free)
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/invalid_bool.stderr b/tests/fail/validity/invalid_bool.stderr
index d17319d2dce..756c094d6e8 100644
--- a/tests/fail/validity/invalid_bool.stderr
+++ b/tests/fail/validity/invalid_bool.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered 0x02, but expected a boolean
+error: Undefined Behavior: constructing invalid value: encountered 0x02, but expected a boolean
   --> $DIR/invalid_bool.rs:LL:CC
    |
 LL |     let _b = unsafe { std::mem::transmute::<u8, bool>(2) };
-   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered 0x02, but expected a boolean
+   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered 0x02, but expected a boolean
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/invalid_bool_uninit.stderr b/tests/fail/validity/invalid_bool_uninit.stderr
index e262e69dc69..5236cab450b 100644
--- a/tests/fail/validity/invalid_bool_uninit.stderr
+++ b/tests/fail/validity/invalid_bool_uninit.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered uninitialized bytes, but expected a boolean
+error: Undefined Behavior: constructing invalid value: encountered uninitialized bytes, but expected a boolean
   --> $DIR/invalid_bool_uninit.rs:LL:CC
    |
 LL |     let _b = unsafe { MyUninit { init: () }.uninit };
-   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered uninitialized bytes, but expected a boolean
+   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered uninitialized bytes, but expected a boolean
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/invalid_char.stderr b/tests/fail/validity/invalid_char.stderr
index 99f5ce0bb21..538af4aefca 100644
--- a/tests/fail/validity/invalid_char.stderr
+++ b/tests/fail/validity/invalid_char.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered $HEX, but expected a valid unicode scalar value (in `0..=$HEX` but not in `$HEX..=$HEX`)
+error: Undefined Behavior: constructing invalid value: encountered $HEX, but expected a valid unicode scalar value (in `0..=$HEX` but not in `$HEX..=$HEX`)
   --> $DIR/invalid_char.rs:LL:CC
    |
 LL |     let _val = match unsafe { std::mem::transmute::<i32, char>(-1) } {
-   |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered $HEX, but expected a valid unicode scalar value (in `0..=$HEX` but not in `$HEX..=$HEX`)
+   |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered $HEX, but expected a valid unicode scalar value (in `0..=$HEX` but not in `$HEX..=$HEX`)
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/invalid_char_uninit.stderr b/tests/fail/validity/invalid_char_uninit.stderr
index b27c9b2bb69..12bc0faa513 100644
--- a/tests/fail/validity/invalid_char_uninit.stderr
+++ b/tests/fail/validity/invalid_char_uninit.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered uninitialized bytes, but expected a valid unicode scalar value (in `0..=$HEX` but not in `$HEX..=$HEX`)
+error: Undefined Behavior: constructing invalid value: encountered uninitialized bytes, but expected a valid unicode scalar value (in `0..=$HEX` but not in `$HEX..=$HEX`)
   --> $DIR/invalid_char_uninit.rs:LL:CC
    |
 LL |     let _b = unsafe { MyUninit { init: () }.uninit };
-   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered uninitialized bytes, but expected a valid unicode scalar value (in `0..=$HEX` but not in `$HEX..=$HEX`)
+   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered uninitialized bytes, but expected a valid unicode scalar value (in `0..=$HEX` but not in `$HEX..=$HEX`)
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/invalid_enum_tag.rs b/tests/fail/validity/invalid_enum_tag.rs
index 9722e6492c8..4bc60ba51e7 100644
--- a/tests/fail/validity/invalid_enum_tag.rs
+++ b/tests/fail/validity/invalid_enum_tag.rs
@@ -7,5 +7,5 @@ pub enum Foo {
 }
 
 fn main() {
-    let _f = unsafe { std::mem::transmute::<i32, Foo>(42) }; //~ ERROR type validation failed at .<enum-tag>: encountered 0x0000002a, but expected a valid enum tag
+    let _f = unsafe { std::mem::transmute::<i32, Foo>(42) }; //~ ERROR constructing invalid value at .<enum-tag>: encountered 0x0000002a, but expected a valid enum tag
 }
diff --git a/tests/fail/validity/invalid_enum_tag.stderr b/tests/fail/validity/invalid_enum_tag.stderr
index c6d862ae1b0..c7014ae71ac 100644
--- a/tests/fail/validity/invalid_enum_tag.stderr
+++ b/tests/fail/validity/invalid_enum_tag.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed at .<enum-tag>: encountered $HEX, but expected a valid enum tag
+error: Undefined Behavior: constructing invalid value at .<enum-tag>: encountered $HEX, but expected a valid enum tag
   --> $DIR/invalid_enum_tag.rs:LL:CC
    |
-LL | ... { std::mem::transmute::<i32, Foo>(42) };
-   |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed at .<enum-tag>: encountered $HEX, but expected a valid enum tag
+LL |     let _f = unsafe { std::mem::transmute::<i32, Foo>(42) };
+   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-tag>: encountered $HEX, but expected a valid enum tag
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/invalid_enum_tag_256variants_uninit.rs b/tests/fail/validity/invalid_enum_tag_256variants_uninit.rs
index b6f86698b3f..7573a64d0eb 100644
--- a/tests/fail/validity/invalid_enum_tag_256variants_uninit.rs
+++ b/tests/fail/validity/invalid_enum_tag_256variants_uninit.rs
@@ -268,5 +268,5 @@ union MyUninit {
 }
 
 fn main() {
-    let _a = unsafe { MyUninit { init: () }.uninit }; //~ ERROR type validation failed at .<enum-tag>: encountered uninitialized bytes, but expected a valid enum tag
+    let _a = unsafe { MyUninit { init: () }.uninit }; //~ ERROR constructing invalid value at .<enum-tag>: encountered uninitialized bytes, but expected a valid enum tag
 }
diff --git a/tests/fail/validity/invalid_enum_tag_256variants_uninit.stderr b/tests/fail/validity/invalid_enum_tag_256variants_uninit.stderr
index 0e924bb741a..c9fd312a96c 100644
--- a/tests/fail/validity/invalid_enum_tag_256variants_uninit.stderr
+++ b/tests/fail/validity/invalid_enum_tag_256variants_uninit.stderr
@@ -1,9 +1,9 @@
 WARNING: `-Zmiri-allow-uninit-numbers` is deprecated and planned to be removed. Please let us know at <https://github.com/rust-lang/miri/issues/2187> if you rely on this flag.
-error: Undefined Behavior: type validation failed at .<enum-tag>: encountered uninitialized bytes, but expected a valid enum tag
+error: Undefined Behavior: constructing invalid value at .<enum-tag>: encountered uninitialized bytes, but expected a valid enum tag
   --> $DIR/invalid_enum_tag_256variants_uninit.rs:LL:CC
    |
 LL |     let _a = unsafe { MyUninit { init: () }.uninit };
-   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed at .<enum-tag>: encountered uninitialized bytes, but expected a valid enum tag
+   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-tag>: encountered uninitialized bytes, but expected a valid enum tag
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/invalid_fnptr_null.stderr b/tests/fail/validity/invalid_fnptr_null.stderr
index e3cea40e0c3..13e8957e615 100644
--- a/tests/fail/validity/invalid_fnptr_null.stderr
+++ b/tests/fail/validity/invalid_fnptr_null.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered a null function pointer
+error: Undefined Behavior: constructing invalid value: encountered a null function pointer
   --> $DIR/invalid_fnptr_null.rs:LL:CC
    |
 LL |     let _b: fn() = unsafe { std::mem::transmute(0usize) };
-   |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered a null function pointer
+   |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a null function pointer
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/invalid_fnptr_uninit.stderr b/tests/fail/validity/invalid_fnptr_uninit.stderr
index 84a5657e787..b64655fa818 100644
--- a/tests/fail/validity/invalid_fnptr_uninit.stderr
+++ b/tests/fail/validity/invalid_fnptr_uninit.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered uninitialized bytes, but expected a proper pointer or integer value
+error: Undefined Behavior: constructing invalid value: encountered uninitialized bytes, but expected a proper pointer or integer value
   --> $DIR/invalid_fnptr_uninit.rs:LL:CC
    |
 LL |     let _b = unsafe { MyUninit { init: () }.uninit };
-   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered uninitialized bytes, but expected a proper pointer or integer value
+   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered uninitialized bytes, but expected a proper pointer or integer value
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/invalid_wide_raw.stderr b/tests/fail/validity/invalid_wide_raw.stderr
index f64b824d6ba..633f8f8adbc 100644
--- a/tests/fail/validity/invalid_wide_raw.stderr
+++ b/tests/fail/validity/invalid_wide_raw.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered dangling vtable pointer in wide pointer
+error: Undefined Behavior: constructing invalid value: encountered dangling vtable pointer in wide pointer
   --> $DIR/invalid_wide_raw.rs:LL:CC
    |
 LL |     dbg!(S { x: unsafe { std::mem::transmute((0usize, 0usize)) } });
-   |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered dangling vtable pointer in wide pointer
+   |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered dangling vtable pointer in wide pointer
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/nonzero.stderr b/tests/fail/validity/nonzero.stderr
index ba01acb6a16..0c6a2417230 100644
--- a/tests/fail/validity/nonzero.stderr
+++ b/tests/fail/validity/nonzero.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered 0, but expected something greater or equal to 1
+error: Undefined Behavior: constructing invalid value: encountered 0, but expected something greater or equal to 1
   --> $DIR/nonzero.rs:LL:CC
    |
 LL |     let _x = Some(unsafe { NonZero(0) });
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered 0, but expected something greater or equal to 1
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered 0, but expected something greater or equal to 1
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/ptr_integer_array_transmute.stderr b/tests/fail/validity/ptr_integer_array_transmute.stderr
index bc2ca54438f..39b4ebfc8f1 100644
--- a/tests/fail/validity/ptr_integer_array_transmute.stderr
+++ b/tests/fail/validity/ptr_integer_array_transmute.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered a pointer, but expected plain (non-pointer) bytes
+error: Undefined Behavior: constructing invalid value: encountered a pointer, but expected plain (non-pointer) bytes
   --> $DIR/ptr_integer_array_transmute.rs:LL:CC
    |
 LL |     let _i: [usize; 1] = unsafe { std::mem::transmute(r) };
-   |                                   ^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered a pointer, but expected plain (non-pointer) bytes
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a pointer, but expected plain (non-pointer) bytes
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/ref_to_uninhabited1.stderr b/tests/fail/validity/ref_to_uninhabited1.stderr
index dbaee46a93b..526b6a4dc25 100644
--- a/tests/fail/validity/ref_to_uninhabited1.stderr
+++ b/tests/fail/validity/ref_to_uninhabited1.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered a box pointing to uninhabited type !
+error: Undefined Behavior: constructing invalid value: encountered a box pointing to uninhabited type !
   --> $DIR/ref_to_uninhabited1.rs:LL:CC
    |
 LL |         let x: Box<!> = transmute(&mut 42);
-   |                         ^^^^^^^^^^^^^^^^^^ type validation failed: encountered a box pointing to uninhabited type !
+   |                         ^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a box pointing to uninhabited type !
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/ref_to_uninhabited2.stderr b/tests/fail/validity/ref_to_uninhabited2.stderr
index 115cdfedf77..297b0540ab0 100644
--- a/tests/fail/validity/ref_to_uninhabited2.stderr
+++ b/tests/fail/validity/ref_to_uninhabited2.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered a reference pointing to uninhabited type (i32, Void)
+error: Undefined Behavior: constructing invalid value: encountered a reference pointing to uninhabited type (i32, Void)
   --> $DIR/ref_to_uninhabited2.rs:LL:CC
    |
 LL |         let _x: &(i32, Void) = transmute(&42);
-   |                                ^^^^^^^^^^^^^^ type validation failed: encountered a reference pointing to uninhabited type (i32, Void)
+   |                                ^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to uninhabited type (i32, Void)
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/too-big-slice.stderr b/tests/fail/validity/too-big-slice.stderr
index 9c8d2929bda..52077f16a1c 100644
--- a/tests/fail/validity/too-big-slice.stderr
+++ b/tests/fail/validity/too-big-slice.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered invalid reference metadata: slice is bigger than largest supported object
+error: Undefined Behavior: constructing invalid value: encountered invalid reference metadata: slice is bigger than largest supported object
   --> $DIR/too-big-slice.rs:LL:CC
    |
 LL |         let _x: &[u8] = mem::transmute((ptr, usize::MAX));
-   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered invalid reference metadata: slice is bigger than largest supported object
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered invalid reference metadata: slice is bigger than largest supported object
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/too-big-unsized.stderr b/tests/fail/validity/too-big-unsized.stderr
index 18dc5d8b9c1..a20f1de6d57 100644
--- a/tests/fail/validity/too-big-unsized.stderr
+++ b/tests/fail/validity/too-big-unsized.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed: encountered invalid reference metadata: total size is bigger than largest supported object
+error: Undefined Behavior: constructing invalid value: encountered invalid reference metadata: total size is bigger than largest supported object
   --> $DIR/too-big-unsized.rs:LL:CC
    |
 LL |         let _x: &MySlice = mem::transmute((ptr, isize::MAX as usize));
-   |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered invalid reference metadata: total size is bigger than largest supported object
+   |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered invalid reference metadata: total size is bigger than largest supported object
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/transmute_through_ptr.rs b/tests/fail/validity/transmute_through_ptr.rs
index 049c57e6193..9db2ba99530 100644
--- a/tests/fail/validity/transmute_through_ptr.rs
+++ b/tests/fail/validity/transmute_through_ptr.rs
@@ -14,6 +14,6 @@ fn main() {
     let mut x = Bool::True;
     evil(&mut x);
     let y = x; // reading this ought to be enough to trigger validation
-    //~^ ERROR type validation failed at .<enum-tag>: encountered 0x0000002c, but expected a valid enum tag
+    //~^ ERROR constructing invalid value at .<enum-tag>: encountered 0x0000002c, but expected a valid enum tag
     println!("{:?}", y); // make sure it is used (and not optimized away)
 }
diff --git a/tests/fail/validity/transmute_through_ptr.stderr b/tests/fail/validity/transmute_through_ptr.stderr
index d06dbe3194f..50f699d7f9b 100644
--- a/tests/fail/validity/transmute_through_ptr.stderr
+++ b/tests/fail/validity/transmute_through_ptr.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed at .<enum-tag>: encountered $HEX, but expected a valid enum tag
+error: Undefined Behavior: constructing invalid value at .<enum-tag>: encountered $HEX, but expected a valid enum tag
   --> $DIR/transmute_through_ptr.rs:LL:CC
    |
 LL |     let y = x; // reading this ought to be enough to trigger validation
-   |             ^ type validation failed at .<enum-tag>: encountered $HEX, but expected a valid enum tag
+   |             ^ constructing invalid value at .<enum-tag>: encountered $HEX, but expected a valid enum tag
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/uninit_float.rs b/tests/fail/validity/uninit_float.rs
index e79cbb45f98..43748570d9a 100644
--- a/tests/fail/validity/uninit_float.rs
+++ b/tests/fail/validity/uninit_float.rs
@@ -2,5 +2,5 @@
 
 fn main() {
     let _val = unsafe { std::mem::MaybeUninit::<f32>::uninit().assume_init() };
-    //~^ ERROR type validation failed at .value: encountered uninitialized bytes, but expected initialized bytes
+    //~^ ERROR constructing invalid value at .value: encountered uninitialized bytes, but expected initialized bytes
 }
diff --git a/tests/fail/validity/uninit_float.stderr b/tests/fail/validity/uninit_float.stderr
index 3f244adbabe..946897bd4ea 100644
--- a/tests/fail/validity/uninit_float.stderr
+++ b/tests/fail/validity/uninit_float.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed at .value: encountered uninitialized bytes, but expected initialized bytes
+error: Undefined Behavior: constructing invalid value at .value: encountered uninitialized bytes, but expected initialized bytes
   --> $DIR/uninit_float.rs:LL:CC
    |
 LL |     let _val = unsafe { std::mem::MaybeUninit::<f32>::uninit().assume_init() };
-   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed at .value: encountered uninitialized bytes, but expected initialized bytes
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .value: encountered uninitialized bytes, but expected initialized bytes
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/uninit_integer.rs b/tests/fail/validity/uninit_integer.rs
index bfa25d6ef35..b5a367ba8cb 100644
--- a/tests/fail/validity/uninit_integer.rs
+++ b/tests/fail/validity/uninit_integer.rs
@@ -2,5 +2,5 @@
 
 fn main() {
     let _val = unsafe { std::mem::MaybeUninit::<usize>::uninit().assume_init() };
-    //~^ ERROR type validation failed at .value: encountered uninitialized bytes, but expected initialized bytes
+    //~^ ERROR constructing invalid value at .value: encountered uninitialized bytes, but expected initialized bytes
 }
diff --git a/tests/fail/validity/uninit_integer.stderr b/tests/fail/validity/uninit_integer.stderr
index e3e2f0a1785..7e9d38a4b7b 100644
--- a/tests/fail/validity/uninit_integer.stderr
+++ b/tests/fail/validity/uninit_integer.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed at .value: encountered uninitialized bytes, but expected initialized bytes
+error: Undefined Behavior: constructing invalid value at .value: encountered uninitialized bytes, but expected initialized bytes
   --> $DIR/uninit_integer.rs:LL:CC
    |
 LL |     let _val = unsafe { std::mem::MaybeUninit::<usize>::uninit().assume_init() };
-   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed at .value: encountered uninitialized bytes, but expected initialized bytes
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .value: encountered uninitialized bytes, but expected initialized bytes
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/validity/uninit_integer_signed.rs b/tests/fail/validity/uninit_integer_signed.rs
index 1764120805c..609bad7e4fb 100644
--- a/tests/fail/validity/uninit_integer_signed.rs
+++ b/tests/fail/validity/uninit_integer_signed.rs
@@ -2,5 +2,5 @@
 
 fn main() {
     let _val = unsafe { std::mem::MaybeUninit::<i32>::uninit().assume_init() };
-    //~^ ERROR type validation failed at .value: encountered uninitialized bytes, but expected initialized bytes
+    //~^ ERROR constructing invalid value at .value: encountered uninitialized bytes, but expected initialized bytes
 }
diff --git a/tests/fail/validity/uninit_integer_signed.stderr b/tests/fail/validity/uninit_integer_signed.stderr
index e6d9b51e40e..bd8ea42c3a4 100644
--- a/tests/fail/validity/uninit_integer_signed.stderr
+++ b/tests/fail/validity/uninit_integer_signed.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: type validation failed at .value: encountered uninitialized bytes, but expected initialized bytes
+error: Undefined Behavior: constructing invalid value at .value: encountered uninitialized bytes, but expected initialized bytes
   --> $DIR/uninit_integer_signed.rs:LL:CC
    |
 LL |     let _val = unsafe { std::mem::MaybeUninit::<i32>::uninit().assume_init() };
-   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed at .value: encountered uninitialized bytes, but expected initialized bytes
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .value: encountered uninitialized bytes, but expected initialized bytes
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information