diff --git a/compiler/rustc_borrowck/src/lib.rs b/compiler/rustc_borrowck/src/lib.rs
index cbf8aa313c5..698fdafc936 100644
--- a/compiler/rustc_borrowck/src/lib.rs
+++ b/compiler/rustc_borrowck/src/lib.rs
@@ -187,10 +187,10 @@ fn do_mir_borrowck<'tcx>(
 
     let location_table = LocationTable::new(body);
 
-    let move_data = MoveData::gather_moves(body, tcx, param_env, |_| true);
+    let move_data = MoveData::gather_moves(body, tcx, |_| true);
     let promoted_move_data = promoted
         .iter_enumerated()
-        .map(|(idx, body)| (idx, MoveData::gather_moves(body, tcx, param_env, |_| true)));
+        .map(|(idx, body)| (idx, MoveData::gather_moves(body, tcx, |_| true)));
 
     let mut flow_inits = MaybeInitializedPlaces::new(tcx, body, &move_data)
         .into_engine(tcx, body)
diff --git a/compiler/rustc_borrowck/src/type_check/mod.rs b/compiler/rustc_borrowck/src/type_check/mod.rs
index 238d7d0749a..7b60a632c30 100644
--- a/compiler/rustc_borrowck/src/type_check/mod.rs
+++ b/compiler/rustc_borrowck/src/type_check/mod.rs
@@ -1128,7 +1128,6 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             }
             let projected_ty = curr_projected_ty.projection_ty_core(
                 tcx,
-                self.param_env,
                 proj,
                 |this, field, ()| {
                     let ty = this.field_ty(tcx, field);
@@ -1919,7 +1918,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                 // than 1.
                 // If the length is larger than 1, the repeat expression will need to copy the
                 // element, so we require the `Copy` trait.
-                if len.try_eval_target_usize(tcx, self.param_env).map_or(true, |len| len > 1) {
+                if len.try_to_target_usize(tcx).is_none_or(|len| len > 1) {
                     match operand {
                         Operand::Copy(..) | Operand::Constant(..) => {
                             // These are always okay: direct use of a const, or a value that can evidently be copied.
diff --git a/compiler/rustc_codegen_cranelift/src/intrinsics/simd.rs b/compiler/rustc_codegen_cranelift/src/intrinsics/simd.rs
index cbe411d78d5..e7f9f894381 100644
--- a/compiler/rustc_codegen_cranelift/src/intrinsics/simd.rs
+++ b/compiler/rustc_codegen_cranelift/src/intrinsics/simd.rs
@@ -133,6 +133,7 @@ pub(super) fn codegen_simd_intrinsic_call<'tcx>(
                 .expect_const()
                 .try_to_valtree()
                 .expect("expected monomorphic const in codegen")
+                .0
                 .unwrap_branch();
 
             assert_eq!(x.layout(), y.layout());
@@ -806,8 +807,10 @@ pub(super) fn codegen_simd_intrinsic_call<'tcx>(
                 ty::Uint(i) if i.bit_width() == Some(expected_int_bits) => m.load_scalar(fx),
                 ty::Array(elem, len)
                     if matches!(elem.kind(), ty::Uint(ty::UintTy::U8))
-                        && len.try_eval_target_usize(fx.tcx, ty::ParamEnv::reveal_all())
-                            == Some(expected_bytes) =>
+                        && len
+                            .try_to_target_usize(fx.tcx)
+                            .expect("expected monomorphic const in codegen")
+                            == expected_bytes =>
                 {
                     m.force_stack(fx).0.load(
                         fx,
@@ -907,8 +910,10 @@ pub(super) fn codegen_simd_intrinsic_call<'tcx>(
                 ty::Uint(i) if i.bit_width() == Some(expected_int_bits) => {}
                 ty::Array(elem, len)
                     if matches!(elem.kind(), ty::Uint(ty::UintTy::U8))
-                        && len.try_eval_target_usize(fx.tcx, ty::ParamEnv::reveal_all())
-                            == Some(expected_bytes) => {}
+                        && len
+                            .try_to_target_usize(fx.tcx)
+                            .expect("expected monomorphic const in codegen")
+                            == expected_bytes => {}
                 _ => {
                     fx.tcx.dcx().span_fatal(
                         span,
diff --git a/compiler/rustc_codegen_gcc/src/intrinsic/simd.rs b/compiler/rustc_codegen_gcc/src/intrinsic/simd.rs
index 4e1b99fdebf..43dbfafa871 100644
--- a/compiler/rustc_codegen_gcc/src/intrinsic/simd.rs
+++ b/compiler/rustc_codegen_gcc/src/intrinsic/simd.rs
@@ -76,8 +76,10 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
             ty::Uint(i) if i.bit_width() == Some(expected_int_bits) => args[0].immediate(),
             ty::Array(elem, len)
                 if matches!(*elem.kind(), ty::Uint(ty::UintTy::U8))
-                    && len.try_eval_target_usize(bx.tcx, ty::ParamEnv::reveal_all())
-                        == Some(expected_bytes) =>
+                    && len
+                        .try_to_target_usize(bx.tcx)
+                        .expect("expected monomorphic const in codegen")
+                        == expected_bytes =>
             {
                 let place = PlaceRef::alloca(bx, args[0].layout);
                 args[0].val.store(bx, place);
@@ -696,8 +698,10 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
             }
             ty::Array(elem, len)
                 if matches!(*elem.kind(), ty::Uint(ty::UintTy::U8))
-                    && len.try_eval_target_usize(bx.tcx, ty::ParamEnv::reveal_all())
-                        == Some(expected_bytes) =>
+                    && len
+                        .try_to_target_usize(bx.tcx)
+                        .expect("expected monomorphic const in codegen")
+                        == expected_bytes =>
             {
                 // Zero-extend iN to the array length:
                 let ze = bx.zext(result, bx.type_ix(expected_bytes * 8));
diff --git a/compiler/rustc_codegen_llvm/src/intrinsic.rs b/compiler/rustc_codegen_llvm/src/intrinsic.rs
index 64f1d21b438..c9a17c9852d 100644
--- a/compiler/rustc_codegen_llvm/src/intrinsic.rs
+++ b/compiler/rustc_codegen_llvm/src/intrinsic.rs
@@ -1179,8 +1179,10 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
             ty::Uint(i) if i.bit_width() == Some(expected_int_bits) => args[0].immediate(),
             ty::Array(elem, len)
                 if matches!(elem.kind(), ty::Uint(ty::UintTy::U8))
-                    && len.try_eval_target_usize(bx.tcx, ty::ParamEnv::reveal_all())
-                        == Some(expected_bytes) =>
+                    && len
+                        .try_to_target_usize(bx.tcx)
+                        .expect("expected monomorphic const in codegen")
+                        == expected_bytes =>
             {
                 let place = PlaceRef::alloca(bx, args[0].layout);
                 args[0].val.store(bx, place);
@@ -1245,12 +1247,7 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
     }
 
     if name == sym::simd_shuffle_generic {
-        let idx = fn_args[2]
-            .expect_const()
-            .eval(tcx, ty::ParamEnv::reveal_all(), span)
-            .unwrap()
-            .1
-            .unwrap_branch();
+        let idx = fn_args[2].expect_const().try_to_valtree().unwrap().0.unwrap_branch();
         let n = idx.len() as u64;
 
         let (out_len, out_ty) = require_simd!(ret_ty, SimdReturn);
@@ -1469,8 +1466,10 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
             }
             ty::Array(elem, len)
                 if matches!(elem.kind(), ty::Uint(ty::UintTy::U8))
-                    && len.try_eval_target_usize(bx.tcx, ty::ParamEnv::reveal_all())
-                        == Some(expected_bytes) =>
+                    && len
+                        .try_to_target_usize(bx.tcx)
+                        .expect("expected monomorphic const in codegen")
+                        == expected_bytes =>
             {
                 // Zero-extend iN to the array length:
                 let ze = bx.zext(i_, bx.type_ix(expected_bytes * 8));
diff --git a/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs b/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
index 369ab387bea..526d2b86d48 100644
--- a/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
+++ b/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
@@ -23,7 +23,6 @@ use rustc_middle::ty::layout::{IntegerExt, TyAndLayout};
 use rustc_middle::ty::{
     self, ExistentialProjection, GenericArgKind, GenericArgsRef, ParamEnv, Ty, TyCtxt,
 };
-use rustc_span::DUMMY_SP;
 use rustc_target::abi::Integer;
 use smallvec::SmallVec;
 
@@ -685,21 +684,25 @@ fn push_const_param<'tcx>(tcx: TyCtxt<'tcx>, ct: ty::Const<'tcx>, output: &mut S
         ty::ConstKind::Param(param) => {
             write!(output, "{}", param.name)
         }
-        ty::ConstKind::Value(ty, _) => {
+        ty::ConstKind::Value(ty, valtree) => {
             match ty.kind() {
                 ty::Int(ity) => {
                     // FIXME: directly extract the bits from a valtree instead of evaluating an
                     // already evaluated `Const` in order to get the bits.
-                    let bits = ct.eval_bits(tcx, ty::ParamEnv::reveal_all());
+                    let bits = ct
+                        .try_to_bits(tcx, ty::ParamEnv::reveal_all())
+                        .expect("expected monomorphic const in codegen");
                     let val = Integer::from_int_ty(&tcx, *ity).size().sign_extend(bits) as i128;
                     write!(output, "{val}")
                 }
                 ty::Uint(_) => {
-                    let val = ct.eval_bits(tcx, ty::ParamEnv::reveal_all());
+                    let val = ct
+                        .try_to_bits(tcx, ty::ParamEnv::reveal_all())
+                        .expect("expected monomorphic const in codegen");
                     write!(output, "{val}")
                 }
                 ty::Bool => {
-                    let val = ct.try_eval_bool(tcx, ty::ParamEnv::reveal_all()).unwrap();
+                    let val = ct.try_to_bool().expect("expected monomorphic const in codegen");
                     write!(output, "{val}")
                 }
                 _ => {
@@ -711,8 +714,9 @@ fn push_const_param<'tcx>(tcx: TyCtxt<'tcx>, ct: ty::Const<'tcx>, output: &mut S
                     // avoiding collisions and will make the emitted type names shorter.
                     let hash_short = tcx.with_stable_hashing_context(|mut hcx| {
                         let mut hasher = StableHasher::new();
-                        let ct = ct.eval(tcx, ty::ParamEnv::reveal_all(), DUMMY_SP).unwrap();
-                        hcx.while_hashing_spans(false, |hcx| ct.hash_stable(hcx, &mut hasher));
+                        hcx.while_hashing_spans(false, |hcx| {
+                            (ty, valtree).hash_stable(hcx, &mut hasher)
+                        });
                         hasher.finish::<Hash64>()
                     });
 
diff --git a/compiler/rustc_const_eval/src/const_eval/mod.rs b/compiler/rustc_const_eval/src/const_eval/mod.rs
index ba19f642795..e2e4754a45c 100644
--- a/compiler/rustc_const_eval/src/const_eval/mod.rs
+++ b/compiler/rustc_const_eval/src/const_eval/mod.rs
@@ -43,7 +43,7 @@ pub(crate) fn try_destructure_mir_constant_for_user_output<'tcx>(
 
     // We go to `usize` as we cannot allocate anything bigger anyway.
     let (field_count, variant, down) = match ty.kind() {
-        ty::Array(_, len) => (len.eval_target_usize(tcx.tcx, param_env) as usize, None, op),
+        ty::Array(_, len) => (len.try_to_target_usize(tcx.tcx)? as usize, None, op),
         ty::Adt(def, _) if def.variants().is_empty() => {
             return None;
         }
diff --git a/compiler/rustc_const_eval/src/interpret/cast.rs b/compiler/rustc_const_eval/src/interpret/cast.rs
index 1def3d08328..64b15611316 100644
--- a/compiler/rustc_const_eval/src/interpret/cast.rs
+++ b/compiler/rustc_const_eval/src/interpret/cast.rs
@@ -391,7 +391,9 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 let ptr = self.read_pointer(src)?;
                 let val = Immediate::new_slice(
                     ptr,
-                    length.eval_target_usize(*self.tcx, self.param_env),
+                    length
+                        .try_to_target_usize(*self.tcx)
+                        .expect("expected monomorphic const in const eval"),
                     self,
                 );
                 self.write_immediate(val, dest)
diff --git a/compiler/rustc_hir_analysis/src/check/check.rs b/compiler/rustc_hir_analysis/src/check/check.rs
index 94da3d4ea84..34f596271aa 100644
--- a/compiler/rustc_hir_analysis/src/check/check.rs
+++ b/compiler/rustc_hir_analysis/src/check/check.rs
@@ -1037,7 +1037,11 @@ fn check_simd(tcx: TyCtxt<'_>, sp: Span, def_id: LocalDefId) {
             return;
         }
 
-        if let Some(len) = len_const.try_eval_target_usize(tcx, tcx.param_env(def.did())) {
+        // FIXME(repr_simd): This check is nice, but perhaps unnecessary due to the fact
+        // we do not expect users to implement their own `repr(simd)` types. If they could,
+        // this check is easily side-steppable by hiding the const behind normalization.
+        // The consequence is that the error is, in general, only observable post-mono.
+        if let Some(len) = len_const.try_to_target_usize(tcx) {
             if len == 0 {
                 struct_span_code_err!(tcx.dcx(), sp, E0075, "SIMD vector cannot be empty").emit();
                 return;
diff --git a/compiler/rustc_hir_analysis/src/check/intrinsicck.rs b/compiler/rustc_hir_analysis/src/check/intrinsicck.rs
index 71eb368185e..bbff00cd3b3 100644
--- a/compiler/rustc_hir_analysis/src/check/intrinsicck.rs
+++ b/compiler/rustc_hir_analysis/src/check/intrinsicck.rs
@@ -76,9 +76,7 @@ impl<'a, 'tcx> InlineAsmCtxt<'a, 'tcx> {
 
                 let (size, ty) = match elem_ty.kind() {
                     ty::Array(ty, len) => {
-                        if let Some(len) =
-                            len.try_eval_target_usize(self.tcx, self.tcx.param_env(adt.did()))
-                        {
+                        if let Some(len) = len.try_to_target_usize(self.tcx) {
                             (len, *ty)
                         } else {
                             return None;
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
index eccb18ad6c4..2bc84d1ac67 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
@@ -1487,7 +1487,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 }
             }
         } else if self.tcx.features().generic_const_exprs {
-            ct.normalize(self.tcx, self.param_env)
+            ct.normalize_internal(self.tcx, self.param_env)
         } else {
             ct
         }
diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs
index 8bd9c899a62..ef8100da9e2 100644
--- a/compiler/rustc_lint/src/builtin.rs
+++ b/compiler/rustc_lint/src/builtin.rs
@@ -2601,7 +2601,7 @@ impl<'tcx> LateLintPass<'tcx> for InvalidValue {
                     ty.tuple_fields().iter().find_map(|field| ty_find_init_error(cx, field, init))
                 }
                 Array(ty, len) => {
-                    if matches!(len.try_eval_target_usize(cx.tcx, cx.param_env), Some(v) if v > 0) {
+                    if matches!(len.try_to_target_usize(cx.tcx), Some(v) if v > 0) {
                         // Array length known at array non-empty -- recurse.
                         ty_find_init_error(cx, *ty, init)
                     } else {
diff --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs
index 1a007250961..ddc18c755a8 100644
--- a/compiler/rustc_lint/src/unused.rs
+++ b/compiler/rustc_lint/src/unused.rs
@@ -346,7 +346,7 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults {
                         None
                     }
                 }
-                ty::Array(ty, len) => match len.try_eval_target_usize(cx.tcx, cx.param_env) {
+                ty::Array(ty, len) => match len.try_to_target_usize(cx.tcx) {
                     // If the array is empty we don't lint, to avoid false positives
                     Some(0) | None => None,
                     // If the array is definitely non-empty, we can do `#[must_use]` checking.
diff --git a/compiler/rustc_middle/src/mir/consts.rs b/compiler/rustc_middle/src/mir/consts.rs
index 4262460d928..465aa0eee03 100644
--- a/compiler/rustc_middle/src/mir/consts.rs
+++ b/compiler/rustc_middle/src/mir/consts.rs
@@ -1,5 +1,6 @@
 use std::fmt::{self, Debug, Display, Formatter};
 
+use either::Either;
 use rustc_hir::def_id::DefId;
 use rustc_macros::{HashStable, Lift, TyDecodable, TyEncodable, TypeFoldable, TypeVisitable};
 use rustc_session::RemapFileNameExt;
@@ -320,8 +321,14 @@ impl<'tcx> Const<'tcx> {
             Const::Ty(_, c) => {
                 // We want to consistently have a "clean" value for type system constants (i.e., no
                 // data hidden in the padding), so we always go through a valtree here.
-                let (ty, val) = c.eval(tcx, param_env, span)?;
-                Ok(tcx.valtree_to_const_val((ty, val)))
+                match c.eval_valtree(tcx, param_env, span) {
+                    Ok((ty, val)) => Ok(tcx.valtree_to_const_val((ty, val))),
+                    Err(Either::Left(_bad_ty)) => Err(tcx
+                        .dcx()
+                        .delayed_bug("`mir::Const::eval` called on a non-valtree-compatible type")
+                        .into()),
+                    Err(Either::Right(e)) => Err(e),
+                }
             }
             Const::Unevaluated(uneval, _) => {
                 // FIXME: We might want to have a `try_eval`-like function on `Unevaluated`
diff --git a/compiler/rustc_middle/src/mir/tcx.rs b/compiler/rustc_middle/src/mir/tcx.rs
index 8d57d0d8654..476e352ed92 100644
--- a/compiler/rustc_middle/src/mir/tcx.rs
+++ b/compiler/rustc_middle/src/mir/tcx.rs
@@ -55,7 +55,7 @@ impl<'tcx> PlaceTy<'tcx> {
     /// `PlaceElem`, where we can just use the `Ty` that is already
     /// stored inline on field projection elems.
     pub fn projection_ty(self, tcx: TyCtxt<'tcx>, elem: PlaceElem<'tcx>) -> PlaceTy<'tcx> {
-        self.projection_ty_core(tcx, ty::ParamEnv::empty(), &elem, |_, _, ty| ty, |_, ty| ty)
+        self.projection_ty_core(tcx, &elem, |_, _, ty| ty, |_, ty| ty)
     }
 
     /// `place_ty.projection_ty_core(tcx, elem, |...| { ... })`
@@ -66,7 +66,6 @@ impl<'tcx> PlaceTy<'tcx> {
     pub fn projection_ty_core<V, T>(
         self,
         tcx: TyCtxt<'tcx>,
-        param_env: ty::ParamEnv<'tcx>,
         elem: &ProjectionElem<V, T>,
         mut handle_field: impl FnMut(&Self, FieldIdx, T) -> Ty<'tcx>,
         mut handle_opaque_cast_and_subtype: impl FnMut(&Self, T) -> Ty<'tcx>,
@@ -93,7 +92,9 @@ impl<'tcx> PlaceTy<'tcx> {
                     ty::Slice(..) => self.ty,
                     ty::Array(inner, _) if !from_end => Ty::new_array(tcx, *inner, to - from),
                     ty::Array(inner, size) if from_end => {
-                        let size = size.eval_target_usize(tcx, param_env);
+                        let size = size
+                            .try_to_target_usize(tcx)
+                            .expect("expected subslice projection on fixed-size array");
                         let len = size - from - to;
                         Ty::new_array(tcx, *inner, len)
                     }
diff --git a/compiler/rustc_middle/src/ty/consts.rs b/compiler/rustc_middle/src/ty/consts.rs
index 389d20f315f..eb715be22b1 100644
--- a/compiler/rustc_middle/src/ty/consts.rs
+++ b/compiler/rustc_middle/src/ty/consts.rs
@@ -398,133 +398,65 @@ impl<'tcx> Const<'tcx> {
         }
     }
 
-    /// Returns the evaluated constant
-    #[inline]
-    pub fn eval(
-        self,
-        tcx: TyCtxt<'tcx>,
-        param_env: ParamEnv<'tcx>,
-        span: Span,
-    ) -> Result<(Ty<'tcx>, ValTree<'tcx>), ErrorHandled> {
-        self.eval_valtree(tcx, param_env, span).map_err(|err| {
-            match err {
-                Either::Right(err) => err,
-                Either::Left(_bad_ty) => {
-                    // This can happen when we run on ill-typed code.
-                    let e = tcx.dcx().span_delayed_bug(
-                        span,
-                        "`ty::Const::eval` called on a non-valtree-compatible type",
-                    );
-                    e.into()
-                }
-            }
-        })
-    }
-
     /// Normalizes the constant to a value or an error if possible.
     #[inline]
-    pub fn normalize(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> Self {
-        match self.eval(tcx, param_env, DUMMY_SP) {
+    pub fn normalize_internal(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> Self {
+        match self.eval_valtree(tcx, param_env, DUMMY_SP) {
             Ok((ty, val)) => Self::new_value(tcx, val, ty),
-            Err(ErrorHandled::Reported(r, _span)) => Self::new_error(tcx, r.into()),
-            Err(ErrorHandled::TooGeneric(_span)) => self,
+            Err(Either::Left(_bad_ty)) => {
+                // This can happen when we run on ill-typed code.
+                Self::new_error(
+                    tcx,
+                    tcx.dcx()
+                        .delayed_bug("`ty::Const::eval` called on a non-valtree-compatible type"),
+                )
+            }
+            Err(Either::Right(ErrorHandled::Reported(r, _span))) => Self::new_error(tcx, r.into()),
+            Err(Either::Right(ErrorHandled::TooGeneric(_span))) => self,
         }
     }
 
-    #[inline]
-    pub fn try_eval_scalar(
-        self,
-        tcx: TyCtxt<'tcx>,
-        param_env: ty::ParamEnv<'tcx>,
-    ) -> Option<(Ty<'tcx>, Scalar)> {
-        let (ty, val) = self.eval(tcx, param_env, DUMMY_SP).ok()?;
-        let val = val.try_to_scalar()?;
-        Some((ty, val))
-    }
-
-    #[inline]
-    /// Attempts to evaluate the given constant to bits. Can fail to evaluate in the presence of
-    /// generics (or erroneous code) or if the value can't be represented as bits (e.g. because it
-    /// contains const generic parameters or pointers).
-    pub fn try_eval_scalar_int(
-        self,
-        tcx: TyCtxt<'tcx>,
-        param_env: ParamEnv<'tcx>,
-    ) -> Option<(Ty<'tcx>, ScalarInt)> {
-        let (ty, scalar) = self.try_eval_scalar(tcx, param_env)?;
-        let val = scalar.try_to_scalar_int().ok()?;
-        Some((ty, val))
-    }
-
-    #[inline]
-    /// Attempts to evaluate the given constant to bits. Can fail to evaluate in the presence of
-    /// generics (or erroneous code) or if the value can't be represented as bits (e.g. because it
-    /// contains const generic parameters or pointers).
-    pub fn try_eval_bits(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> Option<u128> {
-        let (ty, scalar) = self.try_eval_scalar_int(tcx, param_env)?;
-        let size = tcx.layout_of(param_env.with_reveal_all_normalized(tcx).and(ty)).ok()?.size;
-        // if `ty` does not depend on generic parameters, use an empty param_env
-        Some(scalar.to_bits(size))
-    }
-
-    #[inline]
-    /// Panics if the value cannot be evaluated or doesn't contain a valid integer of the given type.
-    pub fn eval_bits(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> u128 {
-        self.try_eval_bits(tcx, param_env)
-            .unwrap_or_else(|| bug!("failed to evalate {:#?} to bits", self))
-    }
-
-    #[inline]
-    pub fn try_eval_target_usize(
-        self,
-        tcx: TyCtxt<'tcx>,
-        param_env: ParamEnv<'tcx>,
-    ) -> Option<u64> {
-        let (_, scalar) = self.try_eval_scalar_int(tcx, param_env)?;
-        Some(scalar.to_target_usize(tcx))
-    }
-
-    #[inline]
-    pub fn try_eval_bool(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> Option<bool> {
-        let (_, scalar) = self.try_eval_scalar_int(tcx, param_env)?;
-        scalar.try_into().ok()
-    }
-
-    #[inline]
-    /// Panics if the value cannot be evaluated or doesn't contain a valid `usize`.
-    pub fn eval_target_usize(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> u64 {
-        self.try_eval_target_usize(tcx, param_env)
-            .unwrap_or_else(|| bug!("expected usize, got {:#?}", self))
-    }
-
     /// Panics if self.kind != ty::ConstKind::Value
-    pub fn to_valtree(self) -> ty::ValTree<'tcx> {
+    pub fn to_valtree(self) -> (ty::ValTree<'tcx>, Ty<'tcx>) {
         match self.kind() {
-            ty::ConstKind::Value(_, valtree) => valtree,
+            ty::ConstKind::Value(ty, valtree) => (valtree, ty),
             _ => bug!("expected ConstKind::Value, got {:?}", self.kind()),
         }
     }
 
     /// Attempts to convert to a `ValTree`
-    pub fn try_to_valtree(self) -> Option<ty::ValTree<'tcx>> {
+    pub fn try_to_valtree(self) -> Option<(ty::ValTree<'tcx>, Ty<'tcx>)> {
         match self.kind() {
-            ty::ConstKind::Value(_, valtree) => Some(valtree),
+            ty::ConstKind::Value(ty, valtree) => Some((valtree, ty)),
             _ => None,
         }
     }
 
     #[inline]
-    pub fn try_to_scalar(self) -> Option<Scalar> {
-        self.try_to_valtree()?.try_to_scalar()
+    pub fn try_to_scalar(self) -> Option<(Scalar, Ty<'tcx>)> {
+        let (valtree, ty) = self.try_to_valtree()?;
+        Some((valtree.try_to_scalar()?, ty))
     }
 
     pub fn try_to_bool(self) -> Option<bool> {
-        self.try_to_valtree()?.try_to_scalar_int()?.try_to_bool().ok()
+        self.try_to_valtree()?.0.try_to_scalar_int()?.try_to_bool().ok()
     }
 
     #[inline]
     pub fn try_to_target_usize(self, tcx: TyCtxt<'tcx>) -> Option<u64> {
-        self.try_to_valtree()?.try_to_target_usize(tcx)
+        self.try_to_valtree()?.0.try_to_target_usize(tcx)
+    }
+
+    #[inline]
+    /// Attempts to evaluate the given constant to bits. Can fail to evaluate in the presence of
+    /// generics (or erroneous code) or if the value can't be represented as bits (e.g. because it
+    /// contains const generic parameters or pointers).
+    pub fn try_to_bits(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> Option<u128> {
+        let (scalar, ty) = self.try_to_scalar()?;
+        let scalar = scalar.try_to_scalar_int().ok()?;
+        let size = tcx.layout_of(param_env.with_reveal_all_normalized(tcx).and(ty)).ok()?.size;
+        // if `ty` does not depend on generic parameters, use an empty param_env
+        Some(scalar.to_bits(size))
     }
 
     pub fn is_ct_infer(self) -> bool {
diff --git a/compiler/rustc_middle/src/ty/inhabitedness/inhabited_predicate.rs b/compiler/rustc_middle/src/ty/inhabitedness/inhabited_predicate.rs
index 54b8507babf..bf741f63a3d 100644
--- a/compiler/rustc_middle/src/ty/inhabitedness/inhabited_predicate.rs
+++ b/compiler/rustc_middle/src/ty/inhabitedness/inhabited_predicate.rs
@@ -85,7 +85,7 @@ impl<'tcx> InhabitedPredicate<'tcx> {
         match self {
             Self::False => Ok(false),
             Self::True => Ok(true),
-            Self::ConstIsZero(const_) => match const_.try_eval_target_usize(tcx, param_env) {
+            Self::ConstIsZero(const_) => match const_.try_to_target_usize(tcx) {
                 None | Some(0) => Ok(true),
                 Some(1..) => Ok(false),
             },
diff --git a/compiler/rustc_middle/src/ty/layout.rs b/compiler/rustc_middle/src/ty/layout.rs
index 6c12b691c26..3670b6bbc77 100644
--- a/compiler/rustc_middle/src/ty/layout.rs
+++ b/compiler/rustc_middle/src/ty/layout.rs
@@ -397,7 +397,7 @@ impl<'tcx> SizeSkeleton<'tcx> {
                 }
             }
             ty::Array(inner, len) if tcx.features().transmute_generic_consts => {
-                let len_eval = len.try_eval_target_usize(tcx, param_env);
+                let len_eval = len.try_to_target_usize(tcx);
                 if len_eval == Some(0) {
                     return Ok(SizeSkeleton::Known(Size::from_bytes(0), None));
                 }
diff --git a/compiler/rustc_middle/src/ty/sty.rs b/compiler/rustc_middle/src/ty/sty.rs
index 3f00458d195..74de378c4d7 100644
--- a/compiler/rustc_middle/src/ty/sty.rs
+++ b/compiler/rustc_middle/src/ty/sty.rs
@@ -1117,7 +1117,12 @@ impl<'tcx> Ty<'tcx> {
         // The way we evaluate the `N` in `[T; N]` here only works since we use
         // `simd_size_and_type` post-monomorphization. It will probably start to ICE
         // if we use it in generic code. See the `simd-array-trait` ui test.
-        (f0_len.eval_target_usize(tcx, ParamEnv::empty()), *f0_elem_ty)
+        (
+            f0_len
+                .try_to_target_usize(tcx)
+                .expect("expected SIMD field to have definite array size"),
+            *f0_elem_ty,
+        )
     }
 
     #[inline]
diff --git a/compiler/rustc_mir_dataflow/src/elaborate_drops.rs b/compiler/rustc_mir_dataflow/src/elaborate_drops.rs
index a3b117a3f19..7f2a07e2f5e 100644
--- a/compiler/rustc_mir_dataflow/src/elaborate_drops.rs
+++ b/compiler/rustc_mir_dataflow/src/elaborate_drops.rs
@@ -863,7 +863,7 @@ where
             ty::Adt(def, args) => self.open_drop_for_adt(*def, args),
             ty::Dynamic(..) => self.complete_drop(self.succ, self.unwind),
             ty::Array(ety, size) => {
-                let size = size.try_eval_target_usize(self.tcx(), self.elaborator.param_env());
+                let size = size.try_to_target_usize(self.tcx());
                 self.open_drop_for_array(*ety, size)
             }
             ty::Slice(ety) => self.drop_loop_pair(*ety),
diff --git a/compiler/rustc_mir_dataflow/src/move_paths/builder.rs b/compiler/rustc_mir_dataflow/src/move_paths/builder.rs
index 162245cb950..fd8e403ebc2 100644
--- a/compiler/rustc_mir_dataflow/src/move_paths/builder.rs
+++ b/compiler/rustc_mir_dataflow/src/move_paths/builder.rs
@@ -18,18 +18,12 @@ struct MoveDataBuilder<'a, 'tcx, F> {
     body: &'a Body<'tcx>,
     loc: Location,
     tcx: TyCtxt<'tcx>,
-    param_env: ty::ParamEnv<'tcx>,
     data: MoveData<'tcx>,
     filter: F,
 }
 
 impl<'a, 'tcx, F: Fn(Ty<'tcx>) -> bool> MoveDataBuilder<'a, 'tcx, F> {
-    fn new(
-        body: &'a Body<'tcx>,
-        tcx: TyCtxt<'tcx>,
-        param_env: ty::ParamEnv<'tcx>,
-        filter: F,
-    ) -> Self {
+    fn new(body: &'a Body<'tcx>, tcx: TyCtxt<'tcx>, filter: F) -> Self {
         let mut move_paths = IndexVec::new();
         let mut path_map = IndexVec::new();
         let mut init_path_map = IndexVec::new();
@@ -59,7 +53,6 @@ impl<'a, 'tcx, F: Fn(Ty<'tcx>) -> bool> MoveDataBuilder<'a, 'tcx, F> {
             body,
             loc: Location::START,
             tcx,
-            param_env,
             data: MoveData {
                 moves: IndexVec::new(),
                 loc_map: LocationMap::new(body),
@@ -308,10 +301,9 @@ impl<'a, 'tcx, F: Fn(Ty<'tcx>) -> bool> MoveDataBuilder<'a, 'tcx, F> {
 pub(super) fn gather_moves<'tcx>(
     body: &Body<'tcx>,
     tcx: TyCtxt<'tcx>,
-    param_env: ty::ParamEnv<'tcx>,
     filter: impl Fn(Ty<'tcx>) -> bool,
 ) -> MoveData<'tcx> {
-    let mut builder = MoveDataBuilder::new(body, tcx, param_env, filter);
+    let mut builder = MoveDataBuilder::new(body, tcx, filter);
 
     builder.gather_args();
 
@@ -550,7 +542,9 @@ impl<'a, 'tcx, F: Fn(Ty<'tcx>) -> bool> MoveDataBuilder<'a, 'tcx, F> {
             };
             let base_ty = base_place.ty(self.body, self.tcx).ty;
             let len: u64 = match base_ty.kind() {
-                ty::Array(_, size) => size.eval_target_usize(self.tcx, self.param_env),
+                ty::Array(_, size) => size
+                    .try_to_target_usize(self.tcx)
+                    .expect("expected subslice projection on fixed-size array"),
                 _ => bug!("from_end: false slice pattern of non-array type"),
             };
             for offset in from..to {
diff --git a/compiler/rustc_mir_dataflow/src/move_paths/mod.rs b/compiler/rustc_mir_dataflow/src/move_paths/mod.rs
index bc1177976b5..926bd187431 100644
--- a/compiler/rustc_mir_dataflow/src/move_paths/mod.rs
+++ b/compiler/rustc_mir_dataflow/src/move_paths/mod.rs
@@ -4,7 +4,7 @@ use std::ops::{Index, IndexMut};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_index::{IndexSlice, IndexVec};
 use rustc_middle::mir::*;
-use rustc_middle::ty::{ParamEnv, Ty, TyCtxt};
+use rustc_middle::ty::{Ty, TyCtxt};
 use rustc_span::Span;
 use smallvec::SmallVec;
 
@@ -352,10 +352,9 @@ impl<'tcx> MoveData<'tcx> {
     pub fn gather_moves(
         body: &Body<'tcx>,
         tcx: TyCtxt<'tcx>,
-        param_env: ParamEnv<'tcx>,
         filter: impl Fn(Ty<'tcx>) -> bool,
     ) -> MoveData<'tcx> {
-        builder::gather_moves(body, tcx, param_env, filter)
+        builder::gather_moves(body, tcx, filter)
     }
 
     /// For the move path `mpi`, returns the root local variable that starts the path.
diff --git a/compiler/rustc_mir_dataflow/src/rustc_peek.rs b/compiler/rustc_mir_dataflow/src/rustc_peek.rs
index 75732b19cd0..5727517bd61 100644
--- a/compiler/rustc_mir_dataflow/src/rustc_peek.rs
+++ b/compiler/rustc_mir_dataflow/src/rustc_peek.rs
@@ -40,8 +40,7 @@ pub fn sanity_check<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>) {
         debug!("running rustc_peek::SanityCheck on {}", tcx.def_path_str(def_id));
     }
 
-    let param_env = tcx.param_env(def_id);
-    let move_data = MoveData::gather_moves(body, tcx, param_env, |_| true);
+    let move_data = MoveData::gather_moves(body, tcx, |_| true);
 
     if has_rustc_mir_with(tcx, def_id, sym::rustc_peek_maybe_init).is_some() {
         let flow_inits = MaybeInitializedPlaces::new(tcx, body, &move_data)
diff --git a/compiler/rustc_mir_transform/src/coroutine.rs b/compiler/rustc_mir_transform/src/coroutine.rs
index 8f032728f6b..0a413d68020 100644
--- a/compiler/rustc_mir_transform/src/coroutine.rs
+++ b/compiler/rustc_mir_transform/src/coroutine.rs
@@ -1957,7 +1957,8 @@ fn check_must_not_suspend_ty<'tcx>(
             let descr_pre = &format!("{}array{} of ", data.descr_pre, plural_suffix);
             check_must_not_suspend_ty(tcx, ty, hir_id, param_env, SuspendCheckData {
                 descr_pre,
-                plural_len: len.try_eval_target_usize(tcx, param_env).unwrap_or(0) as usize + 1,
+                // FIXME(must_not_suspend): This is wrong. We should handle printing unevaluated consts.
+                plural_len: len.try_to_target_usize(tcx).unwrap_or(0) as usize + 1,
                 ..data
             })
         }
diff --git a/compiler/rustc_mir_transform/src/elaborate_drops.rs b/compiler/rustc_mir_transform/src/elaborate_drops.rs
index f4ac4d9fee6..30e1ac05e03 100644
--- a/compiler/rustc_mir_transform/src/elaborate_drops.rs
+++ b/compiler/rustc_mir_transform/src/elaborate_drops.rs
@@ -58,8 +58,7 @@ impl<'tcx> crate::MirPass<'tcx> for ElaborateDrops {
         let param_env = tcx.param_env_reveal_all_normalized(def_id);
         // For types that do not need dropping, the behaviour is trivial. So we only need to track
         // init/uninit for types that do need dropping.
-        let move_data =
-            MoveData::gather_moves(body, tcx, param_env, |ty| ty.needs_drop(tcx, param_env));
+        let move_data = MoveData::gather_moves(body, tcx, |ty| ty.needs_drop(tcx, param_env));
         let elaborate_patch = {
             let env = MoveDataParamEnv { move_data, param_env };
 
diff --git a/compiler/rustc_mir_transform/src/known_panics_lint.rs b/compiler/rustc_mir_transform/src/known_panics_lint.rs
index 2f97c408f2a..08923748eb2 100644
--- a/compiler/rustc_mir_transform/src/known_panics_lint.rs
+++ b/compiler/rustc_mir_transform/src/known_panics_lint.rs
@@ -602,7 +602,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             Len(place) => {
                 let len = if let ty::Array(_, n) = place.ty(self.local_decls(), self.tcx).ty.kind()
                 {
-                    n.try_eval_target_usize(self.tcx, self.param_env)?
+                    n.try_to_target_usize(self.tcx)?
                 } else {
                     match self.get_const(place)? {
                         Value::Immediate(src) => src.len(&self.ecx).discard_err()?,
diff --git a/compiler/rustc_mir_transform/src/promote_consts.rs b/compiler/rustc_mir_transform/src/promote_consts.rs
index d963ca5c485..86c4b241a2b 100644
--- a/compiler/rustc_mir_transform/src/promote_consts.rs
+++ b/compiler/rustc_mir_transform/src/promote_consts.rs
@@ -329,7 +329,7 @@ impl<'tcx> Validator<'_, 'tcx> {
                     // Determine the type of the thing we are indexing.
                     && let ty::Array(_, len) = place_base.ty(self.body, self.tcx).ty.kind()
                     // It's an array; determine its length.
-                    && let Some(len) = len.try_eval_target_usize(self.tcx, self.param_env)
+                    && let Some(len) = len.try_to_target_usize(self.tcx)
                     // If the index is in-bounds, go ahead.
                     && idx < len
                 {
@@ -407,7 +407,7 @@ impl<'tcx> Validator<'_, 'tcx> {
                 // mutably without consequences. However, only &mut []
                 // is allowed right now.
                 if let ty::Array(_, len) = ty.kind() {
-                    match len.try_eval_target_usize(self.tcx, self.param_env) {
+                    match len.try_to_target_usize(self.tcx) {
                         Some(0) => {}
                         _ => return Err(Unpromotable),
                     }
diff --git a/compiler/rustc_mir_transform/src/remove_uninit_drops.rs b/compiler/rustc_mir_transform/src/remove_uninit_drops.rs
index e6647edf3f5..09969a4c7cc 100644
--- a/compiler/rustc_mir_transform/src/remove_uninit_drops.rs
+++ b/compiler/rustc_mir_transform/src/remove_uninit_drops.rs
@@ -19,8 +19,7 @@ pub(super) struct RemoveUninitDrops;
 impl<'tcx> crate::MirPass<'tcx> for RemoveUninitDrops {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         let param_env = tcx.param_env(body.source.def_id());
-        let move_data =
-            MoveData::gather_moves(body, tcx, param_env, |ty| ty.needs_drop(tcx, param_env));
+        let move_data = MoveData::gather_moves(body, tcx, |ty| ty.needs_drop(tcx, param_env));
 
         let mut maybe_inits = MaybeInitializedPlaces::new(tcx, body, &move_data)
             .into_engine(tcx, body)
diff --git a/compiler/rustc_next_trait_solver/src/solve/mod.rs b/compiler/rustc_next_trait_solver/src/solve/mod.rs
index ff91fa13fd0..a475a58e483 100644
--- a/compiler/rustc_next_trait_solver/src/solve/mod.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/mod.rs
@@ -295,6 +295,37 @@ where
             Ok(ty)
         }
     }
+
+    /// Normalize a const for when it is structurally matched on, or more likely
+    /// when it needs `.try_to_*` called on it (e.g. to turn it into a usize).
+    ///
+    /// This function is necessary in nearly all cases before matching on a const.
+    /// Not doing so is likely to be incomplete and therefore unsound during
+    /// coherence.
+    #[instrument(level = "trace", skip(self, param_env), ret)]
+    fn structurally_normalize_const(
+        &mut self,
+        param_env: I::ParamEnv,
+        ct: I::Const,
+    ) -> Result<I::Const, NoSolution> {
+        if let ty::ConstKind::Unevaluated(..) = ct.kind() {
+            let normalized_ct = self.next_const_infer();
+            let alias_relate_goal = Goal::new(
+                self.cx(),
+                param_env,
+                ty::PredicateKind::AliasRelate(
+                    ct.into(),
+                    normalized_ct.into(),
+                    ty::AliasRelationDirection::Equate,
+                ),
+            );
+            self.add_goal(GoalSource::Misc, alias_relate_goal);
+            self.try_evaluate_added_goals()?;
+            Ok(self.resolve_vars_if_possible(normalized_ct))
+        } else {
+            Ok(ct)
+        }
+    }
 }
 
 fn response_no_constraints_raw<I: Interner>(
diff --git a/compiler/rustc_next_trait_solver/src/solve/trait_goals.rs b/compiler/rustc_next_trait_solver/src/solve/trait_goals.rs
index 2cbed0bceb2..a8d6536baad 100644
--- a/compiler/rustc_next_trait_solver/src/solve/trait_goals.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/trait_goals.rs
@@ -627,11 +627,16 @@ where
         }
 
         ecx.probe_builtin_trait_candidate(BuiltinImplSource::Misc).enter(|ecx| {
+            let assume = ecx.structurally_normalize_const(
+                goal.param_env,
+                goal.predicate.trait_ref.args.const_at(2),
+            )?;
+
             let certainty = ecx.is_transmutable(
                 goal.param_env,
                 goal.predicate.trait_ref.args.type_at(0),
                 goal.predicate.trait_ref.args.type_at(1),
-                goal.predicate.trait_ref.args.const_at(2),
+                assume,
             )?;
             ecx.evaluate_added_goals_and_make_canonical_response(certainty)
         })
diff --git a/compiler/rustc_sanitizers/src/cfi/typeid/itanium_cxx_abi/encode.rs b/compiler/rustc_sanitizers/src/cfi/typeid/itanium_cxx_abi/encode.rs
index 53834198f63..ca75952fe3d 100644
--- a/compiler/rustc_sanitizers/src/cfi/typeid/itanium_cxx_abi/encode.rs
+++ b/compiler/rustc_sanitizers/src/cfi/typeid/itanium_cxx_abi/encode.rs
@@ -133,7 +133,9 @@ fn encode_const<'tcx>(
             // bool value false is encoded as 0 and true as 1.
             match ct_ty.kind() {
                 ty::Int(ity) => {
-                    let bits = c.eval_bits(tcx, ty::ParamEnv::reveal_all());
+                    let bits = c
+                        .try_to_bits(tcx, ty::ParamEnv::reveal_all())
+                        .expect("expected monomorphic const in cfi");
                     let val = Integer::from_int_ty(&tcx, *ity).size().sign_extend(bits) as i128;
                     if val < 0 {
                         s.push('n');
@@ -141,7 +143,9 @@ fn encode_const<'tcx>(
                     let _ = write!(s, "{val}");
                 }
                 ty::Uint(_) => {
-                    let val = c.eval_bits(tcx, ty::ParamEnv::reveal_all());
+                    let val = c
+                        .try_to_bits(tcx, ty::ParamEnv::reveal_all())
+                        .expect("expected monomorphic const in cfi");
                     let _ = write!(s, "{val}");
                 }
                 ty::Bool => {
diff --git a/compiler/rustc_smir/src/rustc_smir/context.rs b/compiler/rustc_smir/src/rustc_smir/context.rs
index ed5d2d1e799..8fa8f2ac402 100644
--- a/compiler/rustc_smir/src/rustc_smir/context.rs
+++ b/compiler/rustc_smir/src/rustc_smir/context.rs
@@ -406,7 +406,7 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
         let tcx = tables.tcx;
         let mir_const = cnst.internal(&mut *tables, tcx);
         mir_const
-            .try_eval_target_usize(tables.tcx, ParamEnv::empty())
+            .try_to_target_usize(tables.tcx)
             .ok_or_else(|| Error::new(format!("Const `{cnst:?}` cannot be encoded as u64")))
     }
 
diff --git a/compiler/rustc_symbol_mangling/src/v0.rs b/compiler/rustc_symbol_mangling/src/v0.rs
index f3da7ff1ca7..d092fa8f082 100644
--- a/compiler/rustc_symbol_mangling/src/v0.rs
+++ b/compiler/rustc_symbol_mangling/src/v0.rs
@@ -555,7 +555,6 @@ impl<'tcx> Printer<'tcx> for SymbolMangler<'tcx> {
 
     fn print_const(&mut self, ct: ty::Const<'tcx>) -> Result<(), PrintError> {
         // We only mangle a typed value if the const can be evaluated.
-        let ct = ct.normalize(self.tcx, ty::ParamEnv::reveal_all());
         let (ct_ty, valtree) = match ct.kind() {
             ty::ConstKind::Value(ty, val) => (ty, val),
 
@@ -592,7 +591,9 @@ impl<'tcx> Printer<'tcx> for SymbolMangler<'tcx> {
             ty::Uint(_) | ty::Int(_) | ty::Bool | ty::Char => {
                 ct_ty.print(self)?;
 
-                let mut bits = ct.eval_bits(self.tcx, ty::ParamEnv::reveal_all());
+                let mut bits = ct
+                    .try_to_bits(self.tcx, ty::ParamEnv::reveal_all())
+                    .expect("expected const to be monomorphic");
 
                 // Negative integer values are mangled using `n` as a "sign prefix".
                 if let ty::Int(ity) = ct_ty.kind() {
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
index 44373ca4866..322421340e9 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
@@ -2230,124 +2230,143 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         span: Span,
     ) -> GetSafeTransmuteErrorAndReason {
         use rustc_transmute::Answer;
+        self.probe(|_| {
+            // We don't assemble a transmutability candidate for types that are generic
+            // and we should have ambiguity for types that still have non-region infer.
+            if obligation.predicate.has_non_region_param() || obligation.has_non_region_infer() {
+                return GetSafeTransmuteErrorAndReason::Default;
+            }
 
-        // We don't assemble a transmutability candidate for types that are generic
-        // and we should have ambiguity for types that still have non-region infer.
-        if obligation.predicate.has_non_region_param() || obligation.has_non_region_infer() {
-            return GetSafeTransmuteErrorAndReason::Default;
-        }
+            // Erase regions because layout code doesn't particularly care about regions.
+            let trait_ref =
+                self.tcx.erase_regions(self.tcx.instantiate_bound_regions_with_erased(trait_ref));
 
-        // Erase regions because layout code doesn't particularly care about regions.
-        let trait_ref =
-            self.tcx.erase_regions(self.tcx.instantiate_bound_regions_with_erased(trait_ref));
+            let src_and_dst = rustc_transmute::Types {
+                dst: trait_ref.args.type_at(0),
+                src: trait_ref.args.type_at(1),
+            };
 
-        let src_and_dst = rustc_transmute::Types {
-            dst: trait_ref.args.type_at(0),
-            src: trait_ref.args.type_at(1),
-        };
-        let Some(assume) = rustc_transmute::Assume::from_const(
-            self.infcx.tcx,
-            obligation.param_env,
-            trait_ref.args.const_at(2),
-        ) else {
-            self.dcx().span_delayed_bug(
-                span,
-                "Unable to construct rustc_transmute::Assume where it was previously possible",
-            );
-            return GetSafeTransmuteErrorAndReason::Silent;
-        };
+            let ocx = ObligationCtxt::new(self);
+            let Ok(assume) = ocx.structurally_normalize_const(
+                &obligation.cause,
+                obligation.param_env,
+                trait_ref.args.const_at(2),
+            ) else {
+                self.dcx().span_delayed_bug(
+                    span,
+                    "Unable to construct rustc_transmute::Assume where it was previously possible",
+                );
+                return GetSafeTransmuteErrorAndReason::Silent;
+            };
 
-        let dst = trait_ref.args.type_at(0);
-        let src = trait_ref.args.type_at(1);
+            let Some(assume) =
+                rustc_transmute::Assume::from_const(self.infcx.tcx, obligation.param_env, assume)
+            else {
+                self.dcx().span_delayed_bug(
+                    span,
+                    "Unable to construct rustc_transmute::Assume where it was previously possible",
+                );
+                return GetSafeTransmuteErrorAndReason::Silent;
+            };
 
-        let err_msg = format!("`{src}` cannot be safely transmuted into `{dst}`");
+            let dst = trait_ref.args.type_at(0);
+            let src = trait_ref.args.type_at(1);
+            let err_msg = format!("`{src}` cannot be safely transmuted into `{dst}`");
 
-        match rustc_transmute::TransmuteTypeEnv::new(self.infcx).is_transmutable(
-            obligation.cause,
-            src_and_dst,
-            assume,
-        ) {
-            Answer::No(reason) => {
-                let safe_transmute_explanation = match reason {
-                    rustc_transmute::Reason::SrcIsNotYetSupported => {
-                        format!("analyzing the transmutability of `{src}` is not yet supported")
-                    }
+            match rustc_transmute::TransmuteTypeEnv::new(self.infcx).is_transmutable(
+                obligation.cause,
+                src_and_dst,
+                assume,
+            ) {
+                Answer::No(reason) => {
+                    let safe_transmute_explanation = match reason {
+                        rustc_transmute::Reason::SrcIsNotYetSupported => {
+                            format!("analyzing the transmutability of `{src}` is not yet supported")
+                        }
 
-                    rustc_transmute::Reason::DstIsNotYetSupported => {
-                        format!("analyzing the transmutability of `{dst}` is not yet supported")
-                    }
+                        rustc_transmute::Reason::DstIsNotYetSupported => {
+                            format!("analyzing the transmutability of `{dst}` is not yet supported")
+                        }
 
-                    rustc_transmute::Reason::DstIsBitIncompatible => {
-                        format!("at least one value of `{src}` isn't a bit-valid value of `{dst}`")
-                    }
+                        rustc_transmute::Reason::DstIsBitIncompatible => {
+                            format!(
+                                "at least one value of `{src}` isn't a bit-valid value of `{dst}`"
+                            )
+                        }
 
-                    rustc_transmute::Reason::DstUninhabited => {
-                        format!("`{dst}` is uninhabited")
-                    }
+                        rustc_transmute::Reason::DstUninhabited => {
+                            format!("`{dst}` is uninhabited")
+                        }
 
-                    rustc_transmute::Reason::DstMayHaveSafetyInvariants => {
-                        format!("`{dst}` may carry safety invariants")
+                        rustc_transmute::Reason::DstMayHaveSafetyInvariants => {
+                            format!("`{dst}` may carry safety invariants")
+                        }
+                        rustc_transmute::Reason::DstIsTooBig => {
+                            format!("the size of `{src}` is smaller than the size of `{dst}`")
+                        }
+                        rustc_transmute::Reason::DstRefIsTooBig { src, dst } => {
+                            let src_size = src.size;
+                            let dst_size = dst.size;
+                            format!(
+                                "the referent size of `{src}` ({src_size} bytes) \
+                        is smaller than that of `{dst}` ({dst_size} bytes)"
+                            )
+                        }
+                        rustc_transmute::Reason::SrcSizeOverflow => {
+                            format!(
+                                "values of the type `{src}` are too big for the target architecture"
+                            )
+                        }
+                        rustc_transmute::Reason::DstSizeOverflow => {
+                            format!(
+                                "values of the type `{dst}` are too big for the target architecture"
+                            )
+                        }
+                        rustc_transmute::Reason::DstHasStricterAlignment {
+                            src_min_align,
+                            dst_min_align,
+                        } => {
+                            format!(
+                                "the minimum alignment of `{src}` ({src_min_align}) should \
+                        be greater than that of `{dst}` ({dst_min_align})"
+                            )
+                        }
+                        rustc_transmute::Reason::DstIsMoreUnique => {
+                            format!(
+                                "`{src}` is a shared reference, but `{dst}` is a unique reference"
+                            )
+                        }
+                        // Already reported by rustc
+                        rustc_transmute::Reason::TypeError => {
+                            return GetSafeTransmuteErrorAndReason::Silent;
+                        }
+                        rustc_transmute::Reason::SrcLayoutUnknown => {
+                            format!("`{src}` has an unknown layout")
+                        }
+                        rustc_transmute::Reason::DstLayoutUnknown => {
+                            format!("`{dst}` has an unknown layout")
+                        }
+                    };
+                    GetSafeTransmuteErrorAndReason::Error {
+                        err_msg,
+                        safe_transmute_explanation: Some(safe_transmute_explanation),
                     }
-                    rustc_transmute::Reason::DstIsTooBig => {
-                        format!("the size of `{src}` is smaller than the size of `{dst}`")
-                    }
-                    rustc_transmute::Reason::DstRefIsTooBig { src, dst } => {
-                        let src_size = src.size;
-                        let dst_size = dst.size;
-                        format!(
-                            "the referent size of `{src}` ({src_size} bytes) is smaller than that of `{dst}` ({dst_size} bytes)"
-                        )
-                    }
-                    rustc_transmute::Reason::SrcSizeOverflow => {
-                        format!(
-                            "values of the type `{src}` are too big for the target architecture"
-                        )
-                    }
-                    rustc_transmute::Reason::DstSizeOverflow => {
-                        format!(
-                            "values of the type `{dst}` are too big for the target architecture"
-                        )
-                    }
-                    rustc_transmute::Reason::DstHasStricterAlignment {
-                        src_min_align,
-                        dst_min_align,
-                    } => {
-                        format!(
-                            "the minimum alignment of `{src}` ({src_min_align}) should be greater than that of `{dst}` ({dst_min_align})"
-                        )
-                    }
-                    rustc_transmute::Reason::DstIsMoreUnique => {
-                        format!("`{src}` is a shared reference, but `{dst}` is a unique reference")
-                    }
-                    // Already reported by rustc
-                    rustc_transmute::Reason::TypeError => {
-                        return GetSafeTransmuteErrorAndReason::Silent;
-                    }
-                    rustc_transmute::Reason::SrcLayoutUnknown => {
-                        format!("`{src}` has an unknown layout")
-                    }
-                    rustc_transmute::Reason::DstLayoutUnknown => {
-                        format!("`{dst}` has an unknown layout")
-                    }
-                };
-                GetSafeTransmuteErrorAndReason::Error {
-                    err_msg,
-                    safe_transmute_explanation: Some(safe_transmute_explanation),
                 }
+                // Should never get a Yes at this point! We already ran it before, and did not get a Yes.
+                Answer::Yes => span_bug!(
+                    span,
+                    "Inconsistent rustc_transmute::is_transmutable(...) result, got Yes",
+                ),
+                // Reached when a different obligation (namely `Freeze`) causes the
+                // transmutability analysis to fail. In this case, silence the
+                // transmutability error message in favor of that more specific
+                // error.
+                Answer::If(_) => GetSafeTransmuteErrorAndReason::Error {
+                    err_msg,
+                    safe_transmute_explanation: None,
+                },
             }
-            // Should never get a Yes at this point! We already ran it before, and did not get a Yes.
-            Answer::Yes => span_bug!(
-                span,
-                "Inconsistent rustc_transmute::is_transmutable(...) result, got Yes",
-            ),
-            // Reached when a different obligation (namely `Freeze`) causes the
-            // transmutability analysis to fail. In this case, silence the
-            // transmutability error message in favor of that more specific
-            // error.
-            Answer::If(_) => {
-                GetSafeTransmuteErrorAndReason::Error { err_msg, safe_transmute_explanation: None }
-            }
-        }
+        })
     }
 
     /// For effects predicates such as `<u32 as Add>::Effects: Compat<host>`, pretend that the
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs
index cd41ab9fa6c..7f42c932fcf 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs
@@ -231,7 +231,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
             // Arrays give us `[]`, `[{ty}; _]` and `[{ty}; N]`
             if let ty::Array(aty, len) = self_ty.kind() {
                 flags.push((sym::_Self, Some("[]".to_string())));
-                let len = len.try_to_valtree().and_then(|v| v.try_to_target_usize(self.tcx));
+                let len = len.try_to_target_usize(self.tcx);
                 flags.push((sym::_Self, Some(format!("[{aty}; _]"))));
                 if let Some(n) = len {
                     flags.push((sym::_Self, Some(format!("[{aty}; {n}]"))));
diff --git a/compiler/rustc_trait_selection/src/traits/engine.rs b/compiler/rustc_trait_selection/src/traits/engine.rs
index a45ec8b3c44..5e270b62b00 100644
--- a/compiler/rustc_trait_selection/src/traits/engine.rs
+++ b/compiler/rustc_trait_selection/src/traits/engine.rs
@@ -329,4 +329,15 @@ where
             .at(cause, param_env)
             .structurally_normalize(value, &mut **self.engine.borrow_mut())
     }
+
+    pub fn structurally_normalize_const(
+        &self,
+        cause: &ObligationCause<'tcx>,
+        param_env: ty::ParamEnv<'tcx>,
+        value: ty::Const<'tcx>,
+    ) -> Result<ty::Const<'tcx>, Vec<E>> {
+        self.infcx
+            .at(cause, param_env)
+            .structurally_normalize_const(value, &mut **self.engine.borrow_mut())
+    }
 }
diff --git a/compiler/rustc_trait_selection/src/traits/mod.rs b/compiler/rustc_trait_selection/src/traits/mod.rs
index 0fb795fc184..960d34d7253 100644
--- a/compiler/rustc_trait_selection/src/traits/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/mod.rs
@@ -368,7 +368,7 @@ pub fn normalize_param_env_or_error<'tcx>(
                     // should actually be okay since without `feature(generic_const_exprs)` the only
                     // const arguments that have a non-empty param env are array repeat counts. These
                     // do not appear in the type system though.
-                    c.normalize(self.0, ty::ParamEnv::empty())
+                    c.normalize_internal(self.0, ty::ParamEnv::empty())
                 }
             }
 
diff --git a/compiler/rustc_trait_selection/src/traits/normalize.rs b/compiler/rustc_trait_selection/src/traits/normalize.rs
index 7eac3559348..d246d37f748 100644
--- a/compiler/rustc_trait_selection/src/traits/normalize.rs
+++ b/compiler/rustc_trait_selection/src/traits/normalize.rs
@@ -413,7 +413,7 @@ impl<'a, 'b, 'tcx> TypeFolder<TyCtxt<'tcx>> for AssocTypeNormalizer<'a, 'b, 'tcx
                 self.selcx.infcx,
                 &mut self.universes,
                 constant,
-                |constant| constant.normalize(tcx, self.param_env),
+                |constant| constant.normalize_internal(tcx, self.param_env),
             )
         }
     }
diff --git a/compiler/rustc_trait_selection/src/traits/query/normalize.rs b/compiler/rustc_trait_selection/src/traits/query/normalize.rs
index 18412b844ff..01e6516302c 100644
--- a/compiler/rustc_trait_selection/src/traits/query/normalize.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/normalize.rs
@@ -340,7 +340,7 @@ impl<'a, 'tcx> FallibleTypeFolder<TyCtxt<'tcx>> for QueryNormalizer<'a, 'tcx> {
             self.infcx,
             &mut self.universes,
             constant,
-            |constant| constant.normalize(self.infcx.tcx, self.param_env),
+            |constant| constant.normalize_internal(self.infcx.tcx, self.param_env),
         );
         debug!(?constant, ?self.param_env);
         constant.try_super_fold_with(self)
diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
index 0ba3b4e6e55..f78cd6c1aa0 100644
--- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
@@ -405,11 +405,14 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
         let predicate = obligation.predicate.skip_binder();
 
-        let Some(assume) = rustc_transmute::Assume::from_const(
-            self.infcx.tcx,
-            obligation.param_env,
-            predicate.trait_ref.args.const_at(2),
-        ) else {
+        let mut assume = predicate.trait_ref.args.const_at(2);
+        // FIXME(min_generic_const_exprs): We should shallowly normalize this.
+        if self.tcx().features().generic_const_exprs {
+            assume = assume.normalize_internal(self.tcx(), obligation.param_env);
+        }
+        let Some(assume) =
+            rustc_transmute::Assume::from_const(self.infcx.tcx, obligation.param_env, assume)
+        else {
             return Err(Unimplemented);
         };
 
diff --git a/compiler/rustc_trait_selection/src/traits/structural_normalize.rs b/compiler/rustc_trait_selection/src/traits/structural_normalize.rs
index 3814f8112e9..f8d98eb856e 100644
--- a/compiler/rustc_trait_selection/src/traits/structural_normalize.rs
+++ b/compiler/rustc_trait_selection/src/traits/structural_normalize.rs
@@ -82,6 +82,8 @@ impl<'tcx> At<'_, 'tcx> {
             }
 
             Ok(self.infcx.resolve_vars_if_possible(new_infer_ct))
+        } else if self.infcx.tcx.features().generic_const_exprs {
+            Ok(ct.normalize_internal(self.infcx.tcx, self.param_env))
         } else {
             Ok(self.normalize(ct).into_value_registering_obligations(self.infcx, fulfill_cx))
         }
diff --git a/compiler/rustc_transmute/src/lib.rs b/compiler/rustc_transmute/src/lib.rs
index c1d0b704ab2..f7651e49cdd 100644
--- a/compiler/rustc_transmute/src/lib.rs
+++ b/compiler/rustc_transmute/src/lib.rs
@@ -85,7 +85,6 @@ mod rustc {
     use rustc_macros::TypeVisitable;
     use rustc_middle::traits::ObligationCause;
     use rustc_middle::ty::{Const, ParamEnv, Ty, TyCtxt, ValTree};
-    use rustc_span::DUMMY_SP;
 
     use super::*;
 
@@ -134,13 +133,8 @@ mod rustc {
             use rustc_middle::ty::ScalarInt;
             use rustc_span::symbol::sym;
 
-            let Ok((ty, cv)) = c.eval(tcx, param_env, DUMMY_SP) else {
-                return Some(Self {
-                    alignment: true,
-                    lifetimes: true,
-                    safety: true,
-                    validity: true,
-                });
+            let Some((cv, ty)) = c.try_to_valtree() else {
+                return None;
             };
 
             let adt_def = ty.ty_adt_def()?;
diff --git a/compiler/rustc_ty_utils/src/layout.rs b/compiler/rustc_ty_utils/src/layout.rs
index 38b292afe8d..e755e90aa65 100644
--- a/compiler/rustc_ty_utils/src/layout.rs
+++ b/compiler/rustc_ty_utils/src/layout.rs
@@ -176,12 +176,12 @@ fn layout_of_uncached<'tcx>(
                     if let Abi::Scalar(scalar) | Abi::ScalarPair(scalar, _) = &mut layout.abi {
                         if let Some(start) = start {
                             scalar.valid_range_mut().start = start
-                                .try_eval_bits(tcx, param_env)
+                                .try_to_bits(tcx, param_env)
                                 .ok_or_else(|| error(cx, LayoutError::Unknown(ty)))?;
                         }
                         if let Some(end) = end {
                             let mut end = end
-                                .try_eval_bits(tcx, param_env)
+                                .try_to_bits(tcx, param_env)
                                 .ok_or_else(|| error(cx, LayoutError::Unknown(ty)))?;
                             if !include_end {
                                 end = end.wrapping_sub(1);
@@ -321,7 +321,7 @@ fn layout_of_uncached<'tcx>(
             }
 
             let count = count
-                .try_eval_target_usize(tcx, param_env)
+                .try_to_target_usize(tcx)
                 .ok_or_else(|| error(cx, LayoutError::Unknown(ty)))?;
             let element = cx.layout_of(element)?;
             let size = element
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index 1ddad917b78..7d4d8d8941d 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -1817,7 +1817,7 @@ pub(crate) fn clean_ty<'tcx>(ty: &hir::Ty<'tcx>, cx: &mut DocContext<'tcx>) -> T
                         // Only anon consts can implicitly capture params.
                         // FIXME: is this correct behavior?
                         let param_env = cx.tcx.param_env(*def_id);
-                        ct.normalize(cx.tcx, param_env)
+                        cx.tcx.normalize_erasing_regions(param_env, ct)
                     } else {
                         ct
                     };
@@ -2033,8 +2033,8 @@ pub(crate) fn clean_middle_ty<'tcx>(
             Box::new(clean_middle_ty(bound_ty.rebind(ty), cx, None, None)),
             format!("{pat:?}").into_boxed_str(),
         ),
-        ty::Array(ty, mut n) => {
-            n = n.normalize(cx.tcx, ty::ParamEnv::reveal_all());
+        ty::Array(ty, n) => {
+            let n = cx.tcx.normalize_erasing_regions(cx.param_env, n);
             let n = print_const(cx, n);
             Array(Box::new(clean_middle_ty(bound_ty.rebind(ty), cx, None, None)), n.into())
         }
diff --git a/src/tools/clippy/clippy_lints/src/indexing_slicing.rs b/src/tools/clippy/clippy_lints/src/indexing_slicing.rs
index 22e9674714f..ae2c3e0491f 100644
--- a/src/tools/clippy/clippy_lints/src/indexing_slicing.rs
+++ b/src/tools/clippy/clippy_lints/src/indexing_slicing.rs
@@ -114,7 +114,7 @@ impl<'tcx> LateLintPass<'tcx> for IndexingSlicing {
             if let Some(range) = higher::Range::hir(index) {
                 // Ranged indexes, i.e., &x[n..m], &x[n..], &x[..n] and &x[..]
                 if let ty::Array(_, s) = ty.kind() {
-                    let size: u128 = if let Some(size) = s.try_eval_target_usize(cx.tcx, cx.param_env) {
+                    let size: u128 = if let Some(size) = s.try_to_target_usize(cx.tcx) {
                         size.into()
                     } else {
                         return;
@@ -183,7 +183,7 @@ impl<'tcx> LateLintPass<'tcx> for IndexingSlicing {
                             && let ty::Uint(utype) = cx.typeck_results().expr_ty(index).kind()
                             && *utype == ty::UintTy::Usize
                             && let ty::Array(_, s) = ty.kind()
-                            && let Some(size) = s.try_eval_target_usize(cx.tcx, cx.param_env)
+                            && let Some(size) = s.try_to_target_usize(cx.tcx)
                         {
                             // get constant offset and check whether it is in bounds
                             let off = usize::try_from(off).unwrap();
diff --git a/src/tools/clippy/clippy_lints/src/loops/explicit_iter_loop.rs b/src/tools/clippy/clippy_lints/src/loops/explicit_iter_loop.rs
index b134af500f5..022c6bcc70b 100644
--- a/src/tools/clippy/clippy_lints/src/loops/explicit_iter_loop.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/explicit_iter_loop.rs
@@ -30,7 +30,7 @@ pub(super) fn check(
                 return;
             }
         } else if count
-            .try_eval_target_usize(cx.tcx, cx.param_env)
+            .try_to_target_usize(cx.tcx)
             .map_or(true, |x| x > 32)
             && !msrv.meets(msrvs::ARRAY_IMPL_ANY_LEN)
         {
diff --git a/src/tools/clippy/clippy_lints/src/loops/manual_memcpy.rs b/src/tools/clippy/clippy_lints/src/loops/manual_memcpy.rs
index 68d063ad5e5..af089451759 100644
--- a/src/tools/clippy/clippy_lints/src/loops/manual_memcpy.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/manual_memcpy.rs
@@ -472,7 +472,7 @@ fn is_array_length_equal_to_range(cx: &LateContext<'_>, start: &Expr<'_>, end: &
     let arr_ty = cx.typeck_results().expr_ty(arr).peel_refs();
 
     if let ty::Array(_, s) = arr_ty.kind() {
-        let size: u128 = if let Some(size) = s.try_eval_target_usize(cx.tcx, cx.param_env) {
+        let size: u128 = if let Some(size) = s.try_to_target_usize(cx.tcx) {
             size.into()
         } else {
             return false;
diff --git a/src/tools/clippy/clippy_lints/src/loops/needless_range_loop.rs b/src/tools/clippy/clippy_lints/src/loops/needless_range_loop.rs
index 214b8b0f379..2e6442156ef 100644
--- a/src/tools/clippy/clippy_lints/src/loops/needless_range_loop.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/needless_range_loop.rs
@@ -207,7 +207,7 @@ fn is_end_eq_array_len<'tcx>(
     if let ExprKind::Lit(lit) = end.kind
         && let ast::LitKind::Int(end_int, _) = lit.node
         && let ty::Array(_, arr_len_const) = indexed_ty.kind()
-        && let Some(arr_len) = arr_len_const.try_eval_target_usize(cx.tcx, cx.param_env)
+        && let Some(arr_len) = arr_len_const.try_to_target_usize(cx.tcx)
     {
         return match limits {
             ast::RangeLimits::Closed => end_int.get() + 1 >= arr_len.into(),
diff --git a/src/tools/clippy/clippy_lints/src/matches/single_match.rs b/src/tools/clippy/clippy_lints/src/matches/single_match.rs
index 2eda238ae8c..047d070a131 100644
--- a/src/tools/clippy/clippy_lints/src/matches/single_match.rs
+++ b/src/tools/clippy/clippy_lints/src/matches/single_match.rs
@@ -11,7 +11,7 @@ use rustc_hir::def::{DefKind, Res};
 use rustc_hir::intravisit::{Visitor, walk_pat};
 use rustc_hir::{Arm, Expr, ExprKind, HirId, Node, Pat, PatKind, QPath, StmtKind};
 use rustc_lint::LateContext;
-use rustc_middle::ty::{self, AdtDef, ParamEnv, TyCtxt, TypeckResults, VariantDef};
+use rustc_middle::ty::{self, AdtDef, TyCtxt, TypeckResults, VariantDef};
 use rustc_span::{Span, sym};
 
 use super::{MATCH_BOOL, SINGLE_MATCH, SINGLE_MATCH_ELSE};
@@ -67,7 +67,6 @@ pub(crate) fn check<'tcx>(cx: &LateContext<'tcx>, ex: &'tcx Expr<'_>, arms: &'tc
             if v.has_enum {
                 let cx = PatCtxt {
                     tcx: cx.tcx,
-                    param_env: cx.param_env,
                     typeck,
                     arena: DroplessArena::default(),
                 };
@@ -185,7 +184,6 @@ impl<'tcx> Visitor<'tcx> for PatVisitor<'tcx> {
 /// The context needed to manipulate a `PatState`.
 struct PatCtxt<'tcx> {
     tcx: TyCtxt<'tcx>,
-    param_env: ParamEnv<'tcx>,
     typeck: &'tcx TypeckResults<'tcx>,
     arena: DroplessArena,
 }
@@ -334,7 +332,7 @@ impl<'a> PatState<'a> {
                 if match *cx.typeck.pat_ty(pat).peel_refs().kind() {
                     ty::Adt(adt, _) => adt.is_enum() || (adt.is_struct() && !adt.non_enum_variant().fields.is_empty()),
                     ty::Tuple(tys) => !tys.is_empty(),
-                    ty::Array(_, len) => len.try_eval_target_usize(cx.tcx, cx.param_env) != Some(1),
+                    ty::Array(_, len) => len.try_to_target_usize(cx.tcx) != Some(1),
                     ty::Slice(..) => true,
                     _ => false,
                 } =>
@@ -353,7 +351,7 @@ impl<'a> PatState<'a> {
             },
             PatKind::Slice([sub_pat], _, []) | PatKind::Slice([], _, [sub_pat])
                 if let ty::Array(_, len) = *cx.typeck.pat_ty(pat).kind()
-                    && len.try_eval_target_usize(cx.tcx, cx.param_env) == Some(1) =>
+                    && len.try_to_target_usize(cx.tcx) == Some(1) =>
             {
                 self.add_pat(cx, sub_pat)
             },
diff --git a/src/tools/clippy/clippy_lints/src/methods/iter_out_of_bounds.rs b/src/tools/clippy/clippy_lints/src/methods/iter_out_of_bounds.rs
index f198849c5c0..9d462bd1845 100644
--- a/src/tools/clippy/clippy_lints/src/methods/iter_out_of_bounds.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/iter_out_of_bounds.rs
@@ -31,14 +31,14 @@ fn get_iterator_length<'tcx>(cx: &LateContext<'tcx>, iter: &'tcx Expr<'tcx>) ->
         // parameter.
         substs
             .const_at(1)
-            .try_eval_target_usize(cx.tcx, cx.param_env)
+            .try_to_target_usize(cx.tcx)
             .map(u128::from)
     } else if cx.tcx.is_diagnostic_item(sym::SliceIter, did)
         && let ExprKind::MethodCall(_, recv, ..) = iter.kind
     {
         if let ty::Array(_, len) = cx.typeck_results().expr_ty(recv).peel_refs().kind() {
             // For slice::Iter<'_, T>, the receiver might be an array literal: [1,2,3].iter().skip(..)
-            len.try_eval_target_usize(cx.tcx, cx.param_env).map(u128::from)
+            len.try_to_target_usize(cx.tcx).map(u128::from)
         } else if let Some(args) = VecArgs::hir(cx, expr_or_init(cx, recv)) {
             match args {
                 VecArgs::Vec(vec) => vec.len().try_into().ok(),
diff --git a/src/tools/clippy/clippy_lints/src/methods/utils.rs b/src/tools/clippy/clippy_lints/src/methods/utils.rs
index cf0ee569f13..6e39e7be2c4 100644
--- a/src/tools/clippy/clippy_lints/src/methods/utils.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/utils.rs
@@ -18,7 +18,7 @@ pub(super) fn derefs_to_slice<'tcx>(
             ty::Slice(_) => true,
             ty::Adt(..) if let Some(boxed) = ty.boxed_ty() => may_slice(cx, boxed),
             ty::Adt(..) => is_type_diagnostic_item(cx, ty, sym::Vec),
-            ty::Array(_, size) => size.try_eval_target_usize(cx.tcx, cx.param_env).is_some(),
+            ty::Array(_, size) => size.try_to_target_usize(cx.tcx).is_some(),
             ty::Ref(_, inner, _) => may_slice(cx, *inner),
             _ => false,
         }
diff --git a/src/tools/clippy/clippy_lints/src/trailing_empty_array.rs b/src/tools/clippy/clippy_lints/src/trailing_empty_array.rs
index db8c63892b8..52bb7c4bd68 100644
--- a/src/tools/clippy/clippy_lints/src/trailing_empty_array.rs
+++ b/src/tools/clippy/clippy_lints/src/trailing_empty_array.rs
@@ -2,7 +2,7 @@ use clippy_utils::diagnostics::span_lint_and_help;
 use clippy_utils::has_repr_attr;
 use rustc_hir::{Item, ItemKind};
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty::{Const, FeedConstTy};
+use rustc_middle::ty;
 use rustc_session::declare_lint_pass;
 
 declare_clippy_lint! {
@@ -55,16 +55,14 @@ impl<'tcx> LateLintPass<'tcx> for TrailingEmptyArray {
 
 fn is_struct_with_trailing_zero_sized_array<'tcx>(cx: &LateContext<'tcx>, item: &Item<'tcx>) -> bool {
     if let ItemKind::Struct(data, _) = &item.kind
-        // First check if last field is an array
         && let Some(last_field) = data.fields().last()
-        && let rustc_hir::TyKind::Array(_, rustc_hir::ArrayLen::Body(length)) = last_field.ty.kind
-
-        // Then check if that array is zero-sized
-        && let length = Const::from_const_arg(cx.tcx, length, FeedConstTy::No)
-        && let length = length.try_eval_target_usize(cx.tcx, cx.param_env)
-        && let Some(length) = length
+        && let field_ty = cx
+            .tcx
+            .normalize_erasing_regions(cx.param_env, cx.tcx.type_of(last_field.def_id).instantiate_identity())
+        && let ty::Array(_, array_len) = *field_ty.kind()
+        && let Some(0) = array_len.try_to_target_usize(cx.tcx)
     {
-        length == 0
+        true
     } else {
         false
     }
diff --git a/src/tools/clippy/clippy_lints/src/tuple_array_conversions.rs b/src/tools/clippy/clippy_lints/src/tuple_array_conversions.rs
index 3da8a449a7c..07d0f59b91c 100644
--- a/src/tools/clippy/clippy_lints/src/tuple_array_conversions.rs
+++ b/src/tools/clippy/clippy_lints/src/tuple_array_conversions.rs
@@ -190,7 +190,7 @@ fn all_bindings_are_for_conv<'tcx>(
                     tys.len() == elements.len() && tys.iter().chain(final_tys.iter().copied()).all_equal()
                 },
                 (ToType::Tuple, ty::Array(ty, len)) => {
-                    let Some(len) = len.try_eval_target_usize(cx.tcx, cx.param_env) else { return false };
+                    let Some(len) = len.try_to_target_usize(cx.tcx) else { return false };
                     len as usize == elements.len() && final_tys.iter().chain(once(ty)).all_equal()
                 },
                 _ => false,
diff --git a/src/tools/clippy/clippy_utils/src/consts.rs b/src/tools/clippy/clippy_utils/src/consts.rs
index a1cfb7be647..67c31abbdda 100644
--- a/src/tools/clippy/clippy_utils/src/consts.rs
+++ b/src/tools/clippy/clippy_utils/src/consts.rs
@@ -472,7 +472,7 @@ impl<'tcx> ConstEvalCtxt<'tcx> {
             ExprKind::Tup(tup) => self.multi(tup).map(Constant::Tuple),
             ExprKind::Repeat(value, _) => {
                 let n = match self.typeck.expr_ty(e).kind() {
-                    ty::Array(_, n) => n.try_eval_target_usize(self.tcx, self.param_env)?,
+                    ty::Array(_, n) => n.try_to_target_usize(self.tcx)?,
                     _ => span_bug!(e.span, "typeck error"),
                 };
                 self.expr(value).map(|v| Constant::Repeat(Box::new(v), n))
@@ -553,7 +553,7 @@ impl<'tcx> ConstEvalCtxt<'tcx> {
             ExprKind::Array(vec) => self.multi(vec).map(|v| v.is_empty()),
             ExprKind::Repeat(..) => {
                 if let ty::Array(_, n) = self.typeck.expr_ty(e).kind() {
-                    Some(n.try_eval_target_usize(self.tcx, self.param_env)? == 0)
+                    Some(n.try_to_target_usize(self.tcx)? == 0)
                 } else {
                     span_bug!(e.span, "typeck error");
                 }
diff --git a/src/tools/clippy/clippy_utils/src/ty.rs b/src/tools/clippy/clippy_utils/src/ty.rs
index b7a3569ccf0..21793f761d9 100644
--- a/src/tools/clippy/clippy_utils/src/ty.rs
+++ b/src/tools/clippy/clippy_utils/src/ty.rs
@@ -989,7 +989,7 @@ pub fn approx_ty_size<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> u64 {
         (Ok(size), _) => size,
         (Err(_), ty::Tuple(list)) => list.iter().map(|t| approx_ty_size(cx, t)).sum(),
         (Err(_), ty::Array(t, n)) => {
-            n.try_eval_target_usize(cx.tcx, cx.param_env).unwrap_or_default() * approx_ty_size(cx, *t)
+            n.try_to_target_usize(cx.tcx).unwrap_or_default() * approx_ty_size(cx, *t)
         },
         (Err(_), ty::Adt(def, subst)) if def.is_struct() => def
             .variants()
@@ -1207,7 +1207,7 @@ impl<'tcx> InteriorMut<'tcx> {
         let chain = match *ty.kind() {
             ty::RawPtr(inner_ty, _) if !self.ignore_pointers => self.interior_mut_ty_chain(cx, inner_ty),
             ty::Ref(_, inner_ty, _) | ty::Slice(inner_ty) => self.interior_mut_ty_chain(cx, inner_ty),
-            ty::Array(inner_ty, size) if size.try_eval_target_usize(cx.tcx, cx.param_env) != Some(0) => {
+            ty::Array(inner_ty, size) if size.try_to_target_usize(cx.tcx) != Some(0) => {
                 self.interior_mut_ty_chain(cx, inner_ty)
             },
             ty::Tuple(fields) => fields.iter().find_map(|ty| self.interior_mut_ty_chain(cx, ty)),
diff --git a/src/tools/miri/src/intrinsics/simd.rs b/src/tools/miri/src/intrinsics/simd.rs
index 59776a484b5..0799b93dbb0 100644
--- a/src/tools/miri/src/intrinsics/simd.rs
+++ b/src/tools/miri/src/intrinsics/simd.rs
@@ -1,8 +1,7 @@
 use either::Either;
 use rustc_apfloat::{Float, Round};
-use rustc_middle::ty::FloatTy;
-use rustc_middle::ty::layout::{HasParamEnv, LayoutOf};
-use rustc_middle::{mir, ty};
+use rustc_middle::ty::layout::LayoutOf;
+use rustc_middle::{mir, ty, ty::FloatTy};
 use rustc_span::{Symbol, sym};
 use rustc_target::abi::{Endian, HasDataLayout};
 
@@ -633,9 +632,9 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
 
                 let index = generic_args[2]
                     .expect_const()
-                    .eval(*this.tcx, this.param_env(), this.tcx.span)
+                    .try_to_valtree()
                     .unwrap()
-                    .1
+                    .0
                     .unwrap_branch();
                 let index_len = index.len();
 
diff --git a/tests/ui/transmutability/dont-assume-err-is-yes-issue-126377.rs b/tests/ui/transmutability/dont-assume-err-is-yes-issue-126377.rs
new file mode 100644
index 00000000000..eeb0777c856
--- /dev/null
+++ b/tests/ui/transmutability/dont-assume-err-is-yes-issue-126377.rs
@@ -0,0 +1,19 @@
+#![feature(transmutability)]
+#![feature(generic_const_exprs)]
+//~^ WARN the feature `generic_const_exprs` is incomplete
+
+use std::mem::{Assume, TransmuteFrom};
+
+pub fn is_transmutable<const ASSUME_ALIGNMENT: bool>()
+where
+    (): TransmuteFrom<(), { Assume::SAFETY }>,
+{
+}
+
+fn foo<const N: usize>() {
+    is_transmutable::<{}>();
+    //~^ ERROR  the trait bound `(): TransmuteFrom<(), { Assume::SAFETY }>` is not satisfied
+    //~| ERROR mismatched types
+}
+
+fn main() {}
diff --git a/tests/ui/transmutability/dont-assume-err-is-yes-issue-126377.stderr b/tests/ui/transmutability/dont-assume-err-is-yes-issue-126377.stderr
new file mode 100644
index 00000000000..6cb6a85c78a
--- /dev/null
+++ b/tests/ui/transmutability/dont-assume-err-is-yes-issue-126377.stderr
@@ -0,0 +1,34 @@
+warning: the feature `generic_const_exprs` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/dont-assume-err-is-yes-issue-126377.rs:2:12
+   |
+LL | #![feature(generic_const_exprs)]
+   |            ^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #76560 <https://github.com/rust-lang/rust/issues/76560> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+error[E0308]: mismatched types
+  --> $DIR/dont-assume-err-is-yes-issue-126377.rs:14:23
+   |
+LL |     is_transmutable::<{}>();
+   |                       ^^ expected `bool`, found `()`
+
+error[E0277]: the trait bound `(): TransmuteFrom<(), { Assume::SAFETY }>` is not satisfied
+  --> $DIR/dont-assume-err-is-yes-issue-126377.rs:14:23
+   |
+LL |     is_transmutable::<{}>();
+   |                       ^^ the trait `TransmuteFrom<(), { Assume::SAFETY }>` is not implemented for `()`
+   |
+note: required by a bound in `is_transmutable`
+  --> $DIR/dont-assume-err-is-yes-issue-126377.rs:9:9
+   |
+LL | pub fn is_transmutable<const ASSUME_ALIGNMENT: bool>()
+   |        --------------- required by a bound in this function
+LL | where
+LL |     (): TransmuteFrom<(), { Assume::SAFETY }>,
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
+
+error: aborting due to 2 previous errors; 1 warning emitted
+
+Some errors have detailed explanations: E0277, E0308.
+For more information about an error, try `rustc --explain E0277`.