diff --git a/library/core/src/macros/mod.rs b/library/core/src/macros/mod.rs
index 3b026bc0e0f38..da810a12e1dcf 100644
--- a/library/core/src/macros/mod.rs
+++ b/library/core/src/macros/mod.rs
@@ -42,7 +42,7 @@ macro_rules! assert_eq {
                     // The reborrows below are intentional. Without them, the stack slot for the
                     // borrow is initialized even before the values are compared, leading to a
                     // noticeable slow down.
-                    $crate::panicking::assert_failed(kind, &*left_val, &*right_val, $crate::option::Option::None);
+                    $crate::panicking::assert_failed(kind, &*left_val, &*right_val, $crate::option::Option::None, $crate::concat!("assertion failed: `", $crate::stringify!($left), " == ", $crate::stringify!($right), "`"));
                 }
             }
         }
@@ -55,7 +55,7 @@ macro_rules! assert_eq {
                     // The reborrows below are intentional. Without them, the stack slot for the
                     // borrow is initialized even before the values are compared, leading to a
                     // noticeable slow down.
-                    $crate::panicking::assert_failed(kind, &*left_val, &*right_val, $crate::option::Option::Some($crate::format_args!($($arg)+)));
+                    $crate::panicking::assert_failed(kind, &*left_val, &*right_val, $crate::option::Option::Some($crate::format_args!($($arg)+)), $crate::concat!("assertion failed: `", $crate::stringify!($left), " == ", $crate::stringify!($right), "`"));
                 }
             }
         }
@@ -92,7 +92,7 @@ macro_rules! assert_ne {
                     // The reborrows below are intentional. Without them, the stack slot for the
                     // borrow is initialized even before the values are compared, leading to a
                     // noticeable slow down.
-                    $crate::panicking::assert_failed(kind, &*left_val, &*right_val, $crate::option::Option::None);
+                    $crate::panicking::assert_failed(kind, &*left_val, &*right_val, $crate::option::Option::None, $crate::concat!("assertion failed: `", $crate::stringify!($left), " != ", $crate::stringify!($right), "`"));
                 }
             }
         }
@@ -105,7 +105,7 @@ macro_rules! assert_ne {
                     // The reborrows below are intentional. Without them, the stack slot for the
                     // borrow is initialized even before the values are compared, leading to a
                     // noticeable slow down.
-                    $crate::panicking::assert_failed(kind, &*left_val, &*right_val, $crate::option::Option::Some($crate::format_args!($($arg)+)));
+                    $crate::panicking::assert_failed(kind, &*left_val, &*right_val, $crate::option::Option::Some($crate::format_args!($($arg)+)), $crate::concat!("assertion failed: `", $crate::stringify!($left), " != ", $crate::stringify!($right), "`"));
                 }
             }
         }
diff --git a/library/core/src/panicking.rs b/library/core/src/panicking.rs
index 48e90e6d79400..0744d10bcf520 100644
--- a/library/core/src/panicking.rs
+++ b/library/core/src/panicking.rs
@@ -199,17 +199,53 @@ pub enum AssertKind {
 #[cfg_attr(feature = "panic_immediate_abort", inline)]
 #[track_caller]
 #[doc(hidden)]
-pub fn assert_failed<T, U>(
+#[rustc_const_unstable(feature = "const_assert_eq", issue = "none")]
+pub const fn assert_failed<T, U>(
     kind: AssertKind,
     left: &T,
     right: &U,
     args: Option<fmt::Arguments<'_>>,
+    string_for_const_msg: &str,
 ) -> !
 where
     T: fmt::Debug + ?Sized,
     U: fmt::Debug + ?Sized,
 {
-    assert_failed_inner(kind, &left, &right, args)
+    #[track_caller]
+    const fn assert_failed_const_impl<T: ?Sized, U: ?Sized>(
+        _: AssertKind,
+        _: &T,
+        _: &U,
+        _: Option<fmt::Arguments<'_>>,
+        msg: &str,
+    ) -> ! {
+        panic_str(msg)
+    }
+
+    #[track_caller]
+    #[inline]
+    fn assert_failed_runtime_impl<T, U>(
+        kind: AssertKind,
+        left: &T,
+        right: &U,
+        args: Option<fmt::Arguments<'_>>,
+        _: &str,
+    ) -> !
+    where
+        T: fmt::Debug + ?Sized,
+        U: fmt::Debug + ?Sized,
+    {
+        assert_failed_inner(kind, &left, &right, args)
+    }
+
+    // SAFETY: we are panicking in both branches, so this is consistent.
+    unsafe {
+        crate::intrinsics::const_eval_select(
+            (kind, left, right, args, string_for_const_msg),
+            assert_failed_const_impl,
+            assert_failed_runtime_impl,
+        )
+    }
 }
 
 /// Internal function for `assert_match!`
diff --git a/tests/mir-opt/issue_99325.main.built.after.mir b/tests/mir-opt/issue_99325.main.built.after.mir
index 3e035c18db862..aab53e26a0aa8 100644
--- a/tests/mir-opt/issue_99325.main.built.after.mir
+++ b/tests/mir-opt/issue_99325.main.built.after.mir
@@ -27,26 +27,30 @@ fn main() -> () {
     let mut _20: &&[u8; 4];              // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
     let _21: &&[u8; 4];                  // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
     let mut _22: std::option::Option<std::fmt::Arguments<'_>>; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-    let _23: ();                         // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-    let mut _24: (&&[u8], &&[u8; 4]);    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-    let mut _25: &&[u8];                 // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-    let _26: &[u8];                      // in scope 0 at $DIR/issue_99325.rs:+2:16: +2:70
-    let mut _27: &&[u8; 4];              // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-    let _28: &[u8; 4];                   // in scope 0 at $DIR/issue_99325.rs:+2:72: +2:79
-    let _29: &&[u8];                     // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-    let _30: &&[u8; 4];                  // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-    let mut _31: bool;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-    let mut _32: bool;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-    let mut _33: &&[u8];                 // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-    let mut _34: &&[u8; 4];              // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-    let mut _35: !;                      // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-    let _37: !;                          // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-    let mut _38: core::panicking::AssertKind; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-    let mut _39: &&[u8];                 // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-    let _40: &&[u8];                     // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-    let mut _41: &&[u8; 4];              // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-    let _42: &&[u8; 4];                  // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-    let mut _43: std::option::Option<std::fmt::Arguments<'_>>; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let mut _23: &str;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let _24: &str;                       // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let _25: ();                         // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let mut _26: (&&[u8], &&[u8; 4]);    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let mut _27: &&[u8];                 // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let _28: &[u8];                      // in scope 0 at $DIR/issue_99325.rs:+2:16: +2:70
+    let mut _29: &&[u8; 4];              // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let _30: &[u8; 4];                   // in scope 0 at $DIR/issue_99325.rs:+2:72: +2:79
+    let _31: &&[u8];                     // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let _32: &&[u8; 4];                  // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let mut _33: bool;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let mut _34: bool;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let mut _35: &&[u8];                 // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let mut _36: &&[u8; 4];              // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let mut _37: !;                      // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let _39: !;                          // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let mut _40: core::panicking::AssertKind; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let mut _41: &&[u8];                 // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let _42: &&[u8];                     // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let mut _43: &&[u8; 4];              // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let _44: &&[u8; 4];                  // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let mut _45: std::option::Option<std::fmt::Arguments<'_>>; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let mut _46: &str;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let _47: &str;                       // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
     scope 1 {
         debug left_val => _8;            // in scope 1 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         debug right_val => _9;           // in scope 1 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
@@ -56,11 +60,11 @@ fn main() -> () {
         }
     }
     scope 3 {
-        debug left_val => _29;           // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        debug right_val => _30;          // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        let _36: core::panicking::AssertKind; // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        debug left_val => _31;           // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        debug right_val => _32;          // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        let _38: core::panicking::AssertKind; // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         scope 4 {
-            debug kind => _36;           // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+            debug kind => _38;           // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         }
     }
 
@@ -129,10 +133,17 @@ fn main() -> () {
         _20 = &(*_21);                   // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageLive(_22);                // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         _22 = Option::<Arguments<'_>>::None; // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        _16 = core::panicking::assert_failed::<&[u8], &[u8; 4]>(move _17, move _18, move _20, move _22) -> bb19; // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageLive(_23);                // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageLive(_24);                // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _24 = const "assertion failed: `function_with_bytes::<b\"AAAA\">() == &[0x41, 0x41, 0x41, 0x41]`"; // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                          // mir::Constant
                                          // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                         // + literal: Const { ty: for<'a, 'b, 'c> fn(core::panicking::AssertKind, &'a &[u8], &'b &[u8; 4], Option<Arguments<'c>>) -> ! {core::panicking::assert_failed::<&[u8], &[u8; 4]>}, val: Value(<ZST>) }
+                                         // + literal: Const { ty: &str, val: Value(Slice(..)) }
+        _23 = &(*_24);                   // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _16 = core::panicking::assert_failed::<&[u8], &[u8; 4]>(move _17, move _18, move _20, move _22, move _23) -> bb19; // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+                                         // mir::Constant
+                                         // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
+                                         // + literal: Const { ty: for<'a, 'b, 'c, 'd> fn(core::panicking::AssertKind, &'a &[u8], &'b &[u8; 4], Option<Arguments<'c>>, &'d str) -> ! {core::panicking::assert_failed::<&[u8], &[u8; 4]>}, val: Value(<ZST>) }
     }
 
     bb4: {
@@ -140,10 +151,12 @@ fn main() -> () {
     }
 
     bb5: {
+        StorageDead(_23);                // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageDead(_22);                // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageDead(_20);                // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageDead(_18);                // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageDead(_17);                // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageDead(_24);                // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageDead(_21);                // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageDead(_19);                // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageDead(_16);                // scope 2 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
@@ -173,11 +186,11 @@ fn main() -> () {
         StorageDead(_4);                 // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageDead(_2);                 // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageDead(_1);                 // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageLive(_23);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageLive(_24);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageLive(_25);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageLive(_26);                // scope 0 at $DIR/issue_99325.rs:+2:16: +2:70
-        _26 = function_with_bytes::<&*b"AAAA">() -> [return: bb10, unwind: bb19]; // scope 0 at $DIR/issue_99325.rs:+2:16: +2:70
+        StorageLive(_26);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageLive(_27);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageLive(_28);                // scope 0 at $DIR/issue_99325.rs:+2:16: +2:70
+        _28 = function_with_bytes::<&*b"AAAA">() -> [return: bb10, unwind: bb19]; // scope 0 at $DIR/issue_99325.rs:+2:16: +2:70
                                          // mir::Constant
                                          // + span: $DIR/issue_99325.rs:11:16: 11:68
                                          // + user_ty: UserType(1)
@@ -185,63 +198,70 @@ fn main() -> () {
     }
 
     bb10: {
-        _25 = &_26;                      // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageLive(_27);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageLive(_28);                // scope 0 at $DIR/issue_99325.rs:+2:72: +2:79
-        _28 = const b"AAAA";             // scope 0 at $DIR/issue_99325.rs:+2:72: +2:79
+        _27 = &_28;                      // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageLive(_29);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageLive(_30);                // scope 0 at $DIR/issue_99325.rs:+2:72: +2:79
+        _30 = const b"AAAA";             // scope 0 at $DIR/issue_99325.rs:+2:72: +2:79
                                          // mir::Constant
                                          // + span: $DIR/issue_99325.rs:11:72: 11:79
                                          // + literal: Const { ty: &[u8; 4], val: Value(Scalar(alloc4)) }
-        _27 = &_28;                      // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        _24 = (move _25, move _27);      // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _29 = &_30;                      // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _26 = (move _27, move _29);      // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageDead(_29);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageDead(_27);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageDead(_25);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        FakeRead(ForMatchedPlace(None), _24); // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageLive(_29);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        _29 = (_24.0: &&[u8]);           // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageLive(_30);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        _30 = (_24.1: &&[u8; 4]);        // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageLive(_31);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageLive(_32);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        FakeRead(ForMatchedPlace(None), _26); // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageLive(_31);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _31 = (_26.0: &&[u8]);           // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageLive(_32);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _32 = (_26.1: &&[u8; 4]);        // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageLive(_33);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        _33 = &(*_29);                   // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageLive(_34);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        _34 = &(*_30);                   // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        _32 = <&[u8] as PartialEq<&[u8; 4]>>::eq(move _33, move _34) -> [return: bb11, unwind: bb19]; // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageLive(_35);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _35 = &(*_31);                   // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageLive(_36);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _36 = &(*_32);                   // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _34 = <&[u8] as PartialEq<&[u8; 4]>>::eq(move _35, move _36) -> [return: bb11, unwind: bb19]; // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                          // mir::Constant
                                          // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                          // + literal: Const { ty: for<'a, 'b> fn(&'a &[u8], &'b &[u8; 4]) -> bool {<&[u8] as PartialEq<&[u8; 4]>>::eq}, val: Value(<ZST>) }
     }
 
     bb11: {
+        StorageDead(_36);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageDead(_35);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _33 = Not(move _34);             // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageDead(_34);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageDead(_33);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        _31 = Not(move _32);             // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageDead(_32);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        switchInt(move _31) -> [0: bb13, otherwise: bb12]; // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        switchInt(move _33) -> [0: bb13, otherwise: bb12]; // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
     }
 
     bb12: {
-        StorageLive(_36);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        _36 = core::panicking::AssertKind::Eq; // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        FakeRead(ForLet(None), _36);     // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageLive(_37);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageLive(_38);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        _38 = move _36;                  // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageLive(_38);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _38 = core::panicking::AssertKind::Eq; // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        FakeRead(ForLet(None), _38);     // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageLive(_39);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageLive(_40);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        _40 = &(*_29);                   // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        _39 = &(*_40);                   // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _40 = move _38;                  // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageLive(_41);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageLive(_42);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        _42 = &(*_30);                   // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _42 = &(*_31);                   // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         _41 = &(*_42);                   // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageLive(_43);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        _43 = Option::<Arguments<'_>>::None; // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        _37 = core::panicking::assert_failed::<&[u8], &[u8; 4]>(move _38, move _39, move _41, move _43) -> bb19; // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageLive(_44);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _44 = &(*_32);                   // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _43 = &(*_44);                   // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageLive(_45);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _45 = Option::<Arguments<'_>>::None; // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageLive(_46);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageLive(_47);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _47 = const "assertion failed: `function_with_bytes::<{ &[0x41, 0x41, 0x41, 0x41] }>() == b\"AAAA\"`"; // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+                                         // mir::Constant
+                                         // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
+                                         // + literal: Const { ty: &str, val: Value(Slice(..)) }
+        _46 = &(*_47);                   // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _39 = core::panicking::assert_failed::<&[u8], &[u8; 4]>(move _40, move _41, move _43, move _45, move _46) -> bb19; // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                          // mir::Constant
                                          // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                         // + literal: Const { ty: for<'a, 'b, 'c> fn(core::panicking::AssertKind, &'a &[u8], &'b &[u8; 4], Option<Arguments<'c>>) -> ! {core::panicking::assert_failed::<&[u8], &[u8; 4]>}, val: Value(<ZST>) }
+                                         // + literal: Const { ty: for<'a, 'b, 'c, 'd> fn(core::panicking::AssertKind, &'a &[u8], &'b &[u8; 4], Option<Arguments<'c>>, &'d str) -> ! {core::panicking::assert_failed::<&[u8], &[u8; 4]>}, val: Value(<ZST>) }
     }
 
     bb13: {
@@ -249,14 +269,16 @@ fn main() -> () {
     }
 
     bb14: {
+        StorageDead(_46);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageDead(_45);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageDead(_43);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageDead(_41);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageDead(_39);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageDead(_38);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageDead(_42);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageDead(_40);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageDead(_37);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageDead(_36);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageDead(_47);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageDead(_44);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageDead(_42);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageDead(_39);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageDead(_38);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         unreachable;                     // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
     }
 
@@ -265,22 +287,22 @@ fn main() -> () {
     }
 
     bb16: {
-        _23 = const ();                  // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _25 = const ();                  // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         goto -> bb17;                    // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
     }
 
     bb17: {
-        StorageDead(_31);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageDead(_30);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageDead(_29);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageDead(_33);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageDead(_32);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageDead(_31);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         goto -> bb18;                    // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
     }
 
     bb18: {
+        StorageDead(_30);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageDead(_28);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageDead(_26);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageDead(_24);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        StorageDead(_23);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageDead(_25);                // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         _0 = const ();                   // scope 0 at $DIR/issue_99325.rs:+0:15: +3:2
         return;                          // scope 0 at $DIR/issue_99325.rs:+3:2: +3:2
     }
diff --git a/tests/mir-opt/retag.array_casts.SimplifyCfg-elaborate-drops.after.mir b/tests/mir-opt/retag.array_casts.SimplifyCfg-elaborate-drops.after.mir
index 19b726e748453..fa7edf948af68 100644
--- a/tests/mir-opt/retag.array_casts.SimplifyCfg-elaborate-drops.after.mir
+++ b/tests/mir-opt/retag.array_casts.SimplifyCfg-elaborate-drops.after.mir
@@ -30,6 +30,8 @@ fn array_casts() -> () {
     let mut _32: &usize;                 // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
     let _33: &usize;                     // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
     let mut _34: std::option::Option<std::fmt::Arguments<'_>>; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let mut _35: &str;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+    let _36: &str;                       // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
     scope 1 {
         debug x => _1;                   // in scope 1 at $DIR/retag.rs:+1:9: +1:14
         let _2: *mut usize;              // in scope 1 at $DIR/retag.rs:+2:9: +2:10
@@ -45,7 +47,7 @@ fn array_casts() -> () {
                     debug p => _9;       // in scope 5 at $DIR/retag.rs:+6:9: +6:10
                     let _20: &usize;     // in scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                     let _21: &usize;     // in scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                    let mut _35: &usize; // in scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+                    let mut _37: &usize; // in scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                     scope 6 {
                     }
                     scope 7 {
@@ -116,12 +118,12 @@ fn array_casts() -> () {
         _15 = (*_16);                    // scope 6 at $DIR/retag.rs:+7:25: +7:34
         _14 = &_15;                      // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         StorageLive(_18);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        _35 = const _;                   // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _37 = const _;                   // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                          // mir::Constant
                                          // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                          // + literal: Const { ty: &usize, val: Unevaluated(array_casts, [], Some(promoted[0])) }
-        Retag(_35);                      // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        _18 = &(*_35);                   // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        Retag(_37);                      // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _18 = &(*_37);                   // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         Deinit(_13);                     // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         (_13.0: &usize) = move _14;      // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         (_13.1: &usize) = move _18;      // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
@@ -167,10 +169,18 @@ fn array_casts() -> () {
         Deinit(_34);                     // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         discriminant(_34) = 0;           // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
         Retag(_34);                      // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-        _28 = core::panicking::assert_failed::<usize, usize>(move _29, move _30, move _32, move _34); // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageLive(_35);                // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        StorageLive(_36);                // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _36 = const "assertion failed: `unsafe { *p.add(1) } == 1`"; // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                          // mir::Constant
                                          // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                                         // + literal: Const { ty: for<'a, 'b, 'c> fn(core::panicking::AssertKind, &'a usize, &'b usize, Option<Arguments<'c>>) -> ! {core::panicking::assert_failed::<usize, usize>}, val: Value(<ZST>) }
+                                         // + literal: Const { ty: &str, val: Value(Slice(..)) }
+        Retag(_36);                      // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _35 = &(*_36);                   // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+        _28 = core::panicking::assert_failed::<usize, usize>(move _29, move _30, move _32, move _34, move _35); // scope 8 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+                                         // mir::Constant
+                                         // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
+                                         // + literal: Const { ty: for<'a, 'b, 'c, 'd> fn(core::panicking::AssertKind, &'a usize, &'b usize, Option<Arguments<'c>>, &'d str) -> ! {core::panicking::assert_failed::<usize, usize>}, val: Value(<ZST>) }
     }
 
     bb4: {
diff --git a/tests/ui/consts/assert_eq_gate.rs b/tests/ui/consts/assert_eq_gate.rs
new file mode 100644
index 0000000000000..5957b32498bef
--- /dev/null
+++ b/tests/ui/consts/assert_eq_gate.rs
@@ -0,0 +1,5 @@
+const _: () = assert_eq!(1, 1);
+//~^ ERROR `core::panicking::assert_failed` is not yet stable as a const fn
+//~| HELP add `#![feature(const_assert_eq)]` to the crate attributes to enable
+
+fn main() {}
diff --git a/tests/ui/consts/assert_eq_gate.stderr b/tests/ui/consts/assert_eq_gate.stderr
new file mode 100644
index 0000000000000..e684c735c0079
--- /dev/null
+++ b/tests/ui/consts/assert_eq_gate.stderr
@@ -0,0 +1,11 @@
+error: `core::panicking::assert_failed` is not yet stable as a const fn
+  --> $DIR/assert_eq_gate.rs:1:15
+   |
+LL | const _: () = assert_eq!(1, 1);
+   |               ^^^^^^^^^^^^^^^^
+   |
+   = help: add `#![feature(const_assert_eq)]` to the crate attributes to enable
+   = note: this error originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to previous error
+
diff --git a/tests/ui/consts/assertions.rs b/tests/ui/consts/assertions.rs
new file mode 100644
index 0000000000000..75a05a4f54fd5
--- /dev/null
+++ b/tests/ui/consts/assertions.rs
@@ -0,0 +1,15 @@
+#![feature(const_assert_eq)]
+
+const _BAD1: () = {
+    assert_eq!(1, 2)
+}; //~^ ERROR: evaluation of constant value failed
+
+const _BAD2: () = {
+    assert_ne!(1, 1)
+}; //~^ ERROR: evaluation of constant value failed
+
+const _BAD3: () = {
+    assert!(false)
+}; //~^ ERROR: evaluation of constant value failed
+
+fn main() {}
diff --git a/tests/ui/consts/assertions.stderr b/tests/ui/consts/assertions.stderr
new file mode 100644
index 0000000000000..2801d0547752b
--- /dev/null
+++ b/tests/ui/consts/assertions.stderr
@@ -0,0 +1,27 @@
+error[E0080]: evaluation of constant value failed
+  --> $DIR/assertions.rs:4:5
+   |
+LL |     assert_eq!(1, 2)
+   |     ^^^^^^^^^^^^^^^^ the evaluated program panicked at 'assertion failed: `1 == 2`', $DIR/assertions.rs:4:5
+   |
+   = note: this error originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0080]: evaluation of constant value failed
+  --> $DIR/assertions.rs:8:5
+   |
+LL |     assert_ne!(1, 1)
+   |     ^^^^^^^^^^^^^^^^ the evaluated program panicked at 'assertion failed: `1 != 1`', $DIR/assertions.rs:8:5
+   |
+   = note: this error originates in the macro `assert_ne` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0080]: evaluation of constant value failed
+  --> $DIR/assertions.rs:12:5
+   |
+LL |     assert!(false)
+   |     ^^^^^^^^^^^^^^ the evaluated program panicked at 'assertion failed: false', $DIR/assertions.rs:12:5
+   |
+   = note: this error originates in the macro `assert` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0080`.