diff --git a/compiler/rustc_middle/src/thir.rs b/compiler/rustc_middle/src/thir.rs
index e4e3424cb893395edaa1c98a88614d192ebcc65a..b970ee0186c2e745e921b9f33c088e63f9227524 100644
--- a/compiler/rustc_middle/src/thir.rs
+++ b/compiler/rustc_middle/src/thir.rs
@@ -661,7 +661,7 @@ pub enum PatKind<'tcx> {
     /// * Opaque constants, that must not be matched structurally. So anything that does not derive
     ///   `PartialEq` and `Eq`.
     Constant {
-        value: mir::ConstantKind<'tcx>,
+        value: ty::Const<'tcx>,
     },
 
     Range(PatRange<'tcx>),
@@ -691,8 +691,8 @@ pub enum PatKind<'tcx> {
 
 #[derive(Copy, Clone, Debug, PartialEq, HashStable)]
 pub struct PatRange<'tcx> {
-    pub lo: mir::ConstantKind<'tcx>,
-    pub hi: mir::ConstantKind<'tcx>,
+    pub lo: ty::Const<'tcx>,
+    pub hi: ty::Const<'tcx>,
     pub end: RangeEnd,
 }
 
@@ -736,7 +736,11 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
                         Some(adt_def.variant(variant_index))
                     }
                     _ => self.ty.ty_adt_def().and_then(|adt| {
-                        if !adt.is_enum() { Some(adt.non_enum_variant()) } else { None }
+                        if !adt.is_enum() {
+                            Some(adt.non_enum_variant())
+                        } else {
+                            None
+                        }
                     }),
                 };
 
diff --git a/compiler/rustc_middle/src/thir/abstract_const.rs b/compiler/rustc_middle/src/thir/abstract_const.rs
index 4cd195d29646f6f593f3634ea262c6eea00559c5..e02ed414574b43f41bc38d6314694e23e9faf57d 100644
--- a/compiler/rustc_middle/src/thir/abstract_const.rs
+++ b/compiler/rustc_middle/src/thir/abstract_const.rs
@@ -22,7 +22,7 @@ pub enum CastKind {
 /// A node of an `AbstractConst`.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, HashStable, TyEncodable, TyDecodable)]
 pub enum Node<'tcx> {
-    Leaf(mir::ConstantKind<'tcx>),
+    Leaf(ty::Const<'tcx>),
     Binop(mir::BinOp, NodeId, NodeId),
     UnaryOp(mir::UnOp, NodeId),
     FunctionCall(NodeId, &'tcx [NodeId]),
diff --git a/compiler/rustc_middle/src/thir/visit.rs b/compiler/rustc_middle/src/thir/visit.rs
index d052898991ddbe1341193d8b896932bc7c6d4944..abf9696454e8effd2f446bca7cf78348b456d89c 100644
--- a/compiler/rustc_middle/src/thir/visit.rs
+++ b/compiler/rustc_middle/src/thir/visit.rs
@@ -94,13 +94,8 @@ pub fn walk_expr<'a, 'tcx: 'a, V: Visitor<'a, 'tcx>>(visitor: &mut V, expr: &Exp
                 visitor.visit_expr(&visitor.thir()[value])
             }
         }
-<<<<<<< HEAD
         ConstBlock { did: _, substs: _ } => {}
         Repeat { value, count: _ } => {
-=======
-        ConstBlock { value } => visitor.visit_constant(value),
-        Repeat { value, count } => {
->>>>>>> 6064f16d846 (change thir to use mir::ConstantKind instead of ty::Const)
             visitor.visit_expr(&visitor.thir()[value]);
         }
         Array { ref fields } | Tuple { ref fields } => {
diff --git a/compiler/rustc_middle/src/ty/consts/kind.rs b/compiler/rustc_middle/src/ty/consts/kind.rs
index 26dc1a073666193c0a6028b4135eaeeb8b61e19d..777ab7739f08b491e10971398e558db9632ada7c 100644
--- a/compiler/rustc_middle/src/ty/consts/kind.rs
+++ b/compiler/rustc_middle/src/ty/consts/kind.rs
@@ -76,7 +76,11 @@ pub enum ConstKind<'tcx> {
 impl<'tcx> ConstKind<'tcx> {
     #[inline]
     pub fn try_to_value(self) -> Option<ConstValue<'tcx>> {
-        if let ConstKind::Value(val) = self { Some(val) } else { None }
+        if let ConstKind::Value(val) = self {
+            Some(val)
+        } else {
+            None
+        }
     }
 
     #[inline]
@@ -126,6 +130,7 @@ pub fn eval(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> Self {
     #[inline]
     /// Tries to evaluate the constant if it is `Unevaluated`. If that isn't possible or necessary
     /// return `None`.
+    // FIXME(@lcnr): Completely rework the evaluation/normalization system for `ty::Const` once valtrees are merged.
     pub fn try_eval(
         self,
         tcx: TyCtxt<'tcx>,
diff --git a/compiler/rustc_mir_build/src/build/matches/mod.rs b/compiler/rustc_mir_build/src/build/matches/mod.rs
index 23bd085f6f674e32b11cd02a6091e05f15450080..219d101aa7ccfa34b9b95eaca11eb9bad0e94b99 100644
--- a/compiler/rustc_mir_build/src/build/matches/mod.rs
+++ b/compiler/rustc_mir_build/src/build/matches/mod.rs
@@ -964,13 +964,13 @@ enum TestKind<'tcx> {
         ///
         /// For `bool` we always generate two edges, one for `true` and one for
         /// `false`.
-        options: FxIndexMap<ConstantKind<'tcx>, u128>,
+        options: FxIndexMap<ty::Const<'tcx>, u128>,
     },
 
     /// Test for equality with value, possibly after an unsizing coercion to
     /// `ty`,
     Eq {
-        value: ConstantKind<'tcx>,
+        value: ty::Const<'tcx>,
         // Integer types are handled by `SwitchInt`, and constants with ADT
         // types are converted back into patterns, so this can only be `&str`,
         // `&[T]`, `f32` or `f64`.
diff --git a/compiler/rustc_mir_build/src/build/matches/simplify.rs b/compiler/rustc_mir_build/src/build/matches/simplify.rs
index 895df5808dbe16c6eb0cbb2abbeecab6d35c9598..7f53d9dd70502ad10b0f567efdd81d9e77a9f3fa 100644
--- a/compiler/rustc_mir_build/src/build/matches/simplify.rs
+++ b/compiler/rustc_mir_build/src/build/matches/simplify.rs
@@ -228,7 +228,9 @@ fn simplify_match_pair<'pat>(
                     _ => (None, 0),
                 };
                 if let Some((min, max, sz)) = range {
-                    if let (Some(lo), Some(hi)) = (lo.try_to_bits(sz), hi.try_to_bits(sz)) {
+                    if let (Some(lo), Some(hi)) =
+                        (lo.val().try_to_bits(sz), hi.val().try_to_bits(sz))
+                    {
                         // We want to compare ranges numerically, but the order of the bitwise
                         // representation of signed integers does not match their numeric order.
                         // Thus, to correct the ordering, we need to shift the range of signed
diff --git a/compiler/rustc_mir_build/src/build/matches/test.rs b/compiler/rustc_mir_build/src/build/matches/test.rs
index 983987f0799c343986d966e29c2752aa7f2ae23b..806c260d110ea712e8a023b9dbd3d897069c755e 100644
--- a/compiler/rustc_mir_build/src/build/matches/test.rs
+++ b/compiler/rustc_mir_build/src/build/matches/test.rs
@@ -86,7 +86,7 @@ pub(super) fn add_cases_to_switch<'pat>(
         test_place: &PlaceBuilder<'tcx>,
         candidate: &Candidate<'pat, 'tcx>,
         switch_ty: Ty<'tcx>,
-        options: &mut FxIndexMap<ConstantKind<'tcx>, u128>,
+        options: &mut FxIndexMap<ty::Const<'tcx>, u128>,
     ) -> bool {
         let Some(match_pair) = candidate.match_pairs.iter().find(|mp| mp.place == *test_place) else {
             return false;
@@ -264,7 +264,7 @@ pub(super) fn perform_test(
                     );
                 } else if let [success, fail] = *make_target_blocks(self) {
                     assert_eq!(value.ty(), ty);
-                    let expect = self.literal_operand(test.span, value);
+                    let expect = self.literal_operand(test.span, value.into());
                     let val = Operand::Copy(place);
                     self.compare(block, success, fail, source_info, BinOp::Eq, expect, val);
                 } else {
@@ -277,8 +277,8 @@ pub(super) fn perform_test(
                 let target_blocks = make_target_blocks(self);
 
                 // Test `val` by computing `lo <= val && val <= hi`, using primitive comparisons.
-                let lo = self.literal_operand(test.span, lo);
-                let hi = self.literal_operand(test.span, hi);
+                let lo = self.literal_operand(test.span, lo.into());
+                let hi = self.literal_operand(test.span, hi.into());
                 let val = Operand::Copy(place);
 
                 let [success, fail] = *target_blocks else {
@@ -366,11 +366,11 @@ fn non_scalar_compare(
         block: BasicBlock,
         make_target_blocks: impl FnOnce(&mut Self) -> Vec<BasicBlock>,
         source_info: SourceInfo,
-        value: ConstantKind<'tcx>,
+        value: ty::Const<'tcx>,
         place: Place<'tcx>,
         mut ty: Ty<'tcx>,
     ) {
-        let mut expect = self.literal_operand(source_info.span, value);
+        let mut expect = self.literal_operand(source_info.span, value.into());
         let mut val = Operand::Copy(place);
 
         // If we're using `b"..."` as a pattern, we need to insert an
@@ -760,11 +760,7 @@ fn error_simplifyable<'pat>(&mut self, match_pair: &MatchPair<'pat, 'tcx>) -> !
         span_bug!(match_pair.pattern.span, "simplifyable pattern found: {:?}", match_pair.pattern)
     }
 
-    fn const_range_contains(
-        &self,
-        range: PatRange<'tcx>,
-        value: ConstantKind<'tcx>,
-    ) -> Option<bool> {
+    fn const_range_contains(&self, range: PatRange<'tcx>, value: ty::Const<'tcx>) -> Option<bool> {
         use std::cmp::Ordering::*;
 
         let tcx = self.tcx;
@@ -781,7 +777,7 @@ fn const_range_contains(
     fn values_not_contained_in_range(
         &self,
         range: PatRange<'tcx>,
-        options: &FxIndexMap<ConstantKind<'tcx>, u128>,
+        options: &FxIndexMap<ty::Const<'tcx>, u128>,
     ) -> Option<bool> {
         for &val in options.keys() {
             if self.const_range_contains(range, val)? {
diff --git a/compiler/rustc_mir_build/src/build/misc.rs b/compiler/rustc_mir_build/src/build/misc.rs
index 8b1ab482ee8be109c1aa2eb8727f1eec592631b9..84762d602f8db5030f46e9c4046ed9f3000bf833 100644
--- a/compiler/rustc_mir_build/src/build/misc.rs
+++ b/compiler/rustc_mir_build/src/build/misc.rs
@@ -3,6 +3,7 @@
 
 use crate::build::Builder;
 
+use rustc_middle::mir;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, Ty};
 use rustc_span::{Span, DUMMY_SP};
@@ -25,7 +26,11 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 
     /// Convenience function for creating a literal operand, one
     /// without any user type annotation.
-    crate fn literal_operand(&mut self, span: Span, literal: ConstantKind<'tcx>) -> Operand<'tcx> {
+    crate fn literal_operand(
+        &mut self,
+        span: Span,
+        literal: mir::ConstantKind<'tcx>,
+    ) -> Operand<'tcx> {
         let constant = Box::new(Constant { span, user_ty: None, literal });
         Operand::Constant(constant)
     }
diff --git a/compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs b/compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs
index e2b7958bde70dbb0328d1176671b4df3a3e077d3..2298cc7cddf47a26a220a27576e0094586e93bf3 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs
@@ -1,7 +1,7 @@
 use rustc_hir as hir;
 use rustc_index::vec::Idx;
 use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
-use rustc_middle::mir::{self, Field};
+use rustc_middle::mir::Field;
 use rustc_middle::thir::{FieldPat, Pat, PatKind};
 use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::{self, AdtDef, Ty, TyCtxt};
@@ -22,7 +22,7 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
     #[instrument(level = "debug", skip(self))]
     pub(super) fn const_to_pat(
         &self,
-        cv: mir::ConstantKind<'tcx>,
+        cv: ty::Const<'tcx>,
         id: hir::HirId,
         span: Span,
         mir_structural_match_violation: bool,
@@ -152,11 +152,7 @@ fn type_marked_structural(&self, ty: Ty<'tcx>) -> bool {
         ty.is_structural_eq_shallow(self.infcx.tcx)
     }
 
-    fn to_pat(
-        &mut self,
-        cv: mir::ConstantKind<'tcx>,
-        mir_structural_match_violation: bool,
-    ) -> Pat<'tcx> {
+    fn to_pat(&mut self, cv: ty::Const<'tcx>, mir_structural_match_violation: bool) -> Pat<'tcx> {
         trace!(self.treat_byte_string_as_slice);
         // This method is just a wrapper handling a validity check; the heavy lifting is
         // performed by the recursive `recur` method, which is not meant to be
@@ -250,7 +246,7 @@ fn type_may_have_partial_eq_impl(&self, ty: Ty<'tcx>) -> bool {
 
     fn field_pats(
         &self,
-        vals: impl Iterator<Item = mir::ConstantKind<'tcx>>,
+        vals: impl Iterator<Item = ty::Const<'tcx>>,
     ) -> Result<Vec<FieldPat<'tcx>>, FallbackToConstRef> {
         vals.enumerate()
             .map(|(idx, val)| {
@@ -263,7 +259,7 @@ fn field_pats(
     // Recursive helper for `to_pat`; invoke that (instead of calling this directly).
     fn recur(
         &self,
-        cv: mir::ConstantKind<'tcx>,
+        cv: ty::Const<'tcx>,
         mir_structural_match_violation: bool,
     ) -> Result<Pat<'tcx>, FallbackToConstRef> {
         let id = self.id;
@@ -369,7 +365,7 @@ fn recur(
                 PatKind::Wild
             }
             ty::Adt(adt_def, substs) if adt_def.is_enum() => {
-                let destructured = tcx.destructure_mir_constant(param_env.and(cv));
+                let destructured = tcx.destructure_const(param_env.and(cv));
                 PatKind::Variant {
                     adt_def: *adt_def,
                     substs,
@@ -380,12 +376,12 @@ fn recur(
                 }
             }
             ty::Tuple(_) | ty::Adt(_, _) => {
-                let destructured = tcx.destructure_mir_constant(param_env.and(cv));
+                let destructured = tcx.destructure_const(param_env.and(cv));
                 PatKind::Leaf { subpatterns: self.field_pats(destructured.fields.iter().copied())? }
             }
             ty::Array(..) => PatKind::Array {
                 prefix: tcx
-                    .destructure_mir_constant(param_env.and(cv))
+                    .destructure_const(param_env.and(cv))
                     .fields
                     .iter()
                     .map(|val| self.recur(*val, false))
@@ -416,12 +412,12 @@ fn recur(
                 // arrays.
                 ty::Array(..) if !self.treat_byte_string_as_slice => {
                     let old = self.behind_reference.replace(true);
-                    let array = tcx.deref_mir_constant(self.param_env.and(cv));
+                    let array = tcx.deref_const(self.param_env.and(cv));
                     let val = PatKind::Deref {
                         subpattern: Pat {
                             kind: Box::new(PatKind::Array {
                                 prefix: tcx
-                                    .destructure_mir_constant(param_env.and(array))
+                                    .destructure_const(param_env.and(array))
                                     .fields
                                     .iter()
                                     .map(|val| self.recur(*val, false))
@@ -442,12 +438,12 @@ fn recur(
                 // pattern.
                 ty::Slice(elem_ty) => {
                     let old = self.behind_reference.replace(true);
-                    let array = tcx.deref_mir_constant(self.param_env.and(cv));
+                    let array = tcx.deref_const(self.param_env.and(cv));
                     let val = PatKind::Deref {
                         subpattern: Pat {
                             kind: Box::new(PatKind::Slice {
                                 prefix: tcx
-                                    .destructure_mir_constant(param_env.and(array))
+                                    .destructure_const(param_env.and(array))
                                     .fields
                                     .iter()
                                     .map(|val| self.recur(*val, false))
@@ -516,7 +512,7 @@ fn recur(
                         // we fall back to a const pattern. If we do not do this, we may end up with
                         // a !structural-match constant that is not of reference type, which makes it
                         // very hard to invoke `PartialEq::eq` on it as a fallback.
-                        let val = match self.recur(tcx.deref_mir_constant(self.param_env.and(cv)), false) {
+                        let val = match self.recur(tcx.deref_const(self.param_env.and(cv)), false) {
                             Ok(subpattern) => PatKind::Deref { subpattern },
                             Err(_) => PatKind::Constant { value: cv },
                         };
diff --git a/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs b/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs
index d237308fc50c3ae538e047afa48af718ed69cc9c..20229d0a19fde9ccc854e15a8bc306a65ef99d6f 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs
@@ -52,7 +52,7 @@
 use rustc_index::vec::Idx;
 
 use rustc_hir::{HirId, RangeEnd};
-use rustc_middle::mir::{self, Field};
+use rustc_middle::mir::Field;
 use rustc_middle::thir::{FieldPat, Pat, PatKind, PatRange};
 use rustc_middle::ty::layout::IntegerExt;
 use rustc_middle::ty::{self, Ty, TyCtxt, VariantDef};
@@ -136,30 +136,20 @@ fn integral_size_and_signed_bias(tcx: TyCtxt<'_>, ty: Ty<'_>) -> Option<(Size, u
     fn from_const<'tcx>(
         tcx: TyCtxt<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
-        value: mir::ConstantKind<'tcx>,
+        value: ty::Const<'tcx>,
     ) -> Option<IntRange> {
         let ty = value.ty();
         if let Some((target_size, bias)) = Self::integral_size_and_signed_bias(tcx, ty) {
             let val = (|| {
-                match value {
-                    mir::ConstantKind::Val(ConstValue::Scalar(scalar), _) => {
-                        // For this specific pattern we can skip a lot of effort and go
-                        // straight to the result, after doing a bit of checking. (We
-                        // could remove this branch and just fall through, which
-                        // is more general but much slower.)
-                        if let Ok(bits) = scalar.to_bits_or_ptr_internal(target_size) {
-                            return Some(bits);
-                        }
+                if let ty::ConstKind::Value(ConstValue::Scalar(scalar)) = value.val() {
+                    // For this specific pattern we can skip a lot of effort and go
+                    // straight to the result, after doing a bit of checking. (We
+                    // could remove this branch and just fall through, which
+                    // is more general but much slower.)
+                    if let Ok(bits) = scalar.to_bits_or_ptr_internal(target_size) {
+                        return Some(bits);
                     }
-                    mir::ConstantKind::Ty(c) => match c.val() {
-                        ty::ConstKind::Value(_) => bug!(
-                            "encountered ConstValue in mir::ConstantKind::Ty, whereas this is expected to be in ConstantKind::Val"
-                        ),
-                        _ => {}
-                    },
-                    _ => {}
                 }
-
                 // This is a more general form of the previous case.
                 value.try_eval_bits(tcx, param_env, ty)
             })()?;
@@ -244,8 +234,8 @@ fn to_pat<'tcx>(&self, tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Pat<'tcx> {
         let (lo, hi) = (lo ^ bias, hi ^ bias);
 
         let env = ty::ParamEnv::empty().and(ty);
-        let lo_const = mir::ConstantKind::from_bits(tcx, lo, env);
-        let hi_const = mir::ConstantKind::from_bits(tcx, hi, env);
+        let lo_const = ty::Const::from_bits(tcx, lo, env);
+        let hi_const = ty::Const::from_bits(tcx, hi, env);
 
         let kind = if lo == hi {
             PatKind::Constant { value: lo_const }
@@ -640,9 +630,9 @@ pub(super) enum Constructor<'tcx> {
     /// Ranges of integer literal values (`2`, `2..=5` or `2..5`).
     IntRange(IntRange),
     /// Ranges of floating-point literal values (`2.0..=5.2`).
-    FloatRange(mir::ConstantKind<'tcx>, mir::ConstantKind<'tcx>, RangeEnd),
+    FloatRange(ty::Const<'tcx>, ty::Const<'tcx>, RangeEnd),
     /// String literals. Strings are not quite the same as `&[u8]` so we treat them separately.
-    Str(mir::ConstantKind<'tcx>),
+    Str(ty::Const<'tcx>),
     /// Array and slice patterns.
     Slice(Slice),
     /// Constants that must not be matched structurally. They are treated as black
@@ -839,7 +829,8 @@ pub(super) fn is_covered_by<'p>(&self, pcx: PatCtxt<'_, 'p, 'tcx>, other: &Self)
                 }
             }
             (Str(self_val), Str(other_val)) => {
-                // FIXME: there's probably a more direct way of comparing for equality
+                // FIXME Once valtrees are available we can directly use the bytes
+                // in the `Str` variant of the valtree for the comparison here.
                 match compare_const_vals(
                     pcx.cx.tcx,
                     *self_val,
diff --git a/compiler/rustc_mir_build/src/thir/pattern/mod.rs b/compiler/rustc_mir_build/src/thir/pattern/mod.rs
index be11b57c830dc5f3ece37fed7f1fc155f2dcb7ed..38c944b98d3604981e63fb9918ee4e1e98ee846d 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/mod.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/mod.rs
@@ -17,7 +17,7 @@
 use rustc_index::vec::Idx;
 use rustc_middle::mir::interpret::{get_slice_bytes, ConstValue};
 use rustc_middle::mir::interpret::{ErrorHandled, LitToConstError, LitToConstInput};
-use rustc_middle::mir::{self, UserTypeProjection};
+use rustc_middle::mir::UserTypeProjection;
 use rustc_middle::mir::{BorrowKind, Field, Mutability};
 use rustc_middle::thir::{Ascription, BindingMode, FieldPat, Pat, PatKind, PatRange, PatTyProj};
 use rustc_middle::ty::subst::{GenericArg, SubstsRef};
@@ -121,8 +121,8 @@ fn lower_range_expr(
     fn lower_pattern_range(
         &mut self,
         ty: Ty<'tcx>,
-        lo: mir::ConstantKind<'tcx>,
-        hi: mir::ConstantKind<'tcx>,
+        lo: ty::Const<'tcx>,
+        hi: ty::Const<'tcx>,
         end: RangeEnd,
         span: Span,
     ) -> PatKind<'tcx> {
@@ -177,24 +177,18 @@ fn normalize_range_pattern_ends(
         ty: Ty<'tcx>,
         lo: Option<&PatKind<'tcx>>,
         hi: Option<&PatKind<'tcx>>,
-    ) -> Option<(mir::ConstantKind<'tcx>, mir::ConstantKind<'tcx>)> {
+    ) -> Option<(ty::Const<'tcx>, ty::Const<'tcx>)> {
         match (lo, hi) {
             (Some(PatKind::Constant { value: lo }), Some(PatKind::Constant { value: hi })) => {
                 Some((*lo, *hi))
             }
             (Some(PatKind::Constant { value: lo }), None) => {
                 let hi = ty.numeric_max_val(self.tcx)?;
-                Some((
-                    *lo,
-                    mir::ConstantKind::from_bits(self.tcx, hi, ty::ParamEnv::empty().and(ty)),
-                ))
+                Some((*lo, ty::Const::from_bits(self.tcx, hi, ty::ParamEnv::empty().and(ty))))
             }
             (None, Some(PatKind::Constant { value: hi })) => {
                 let lo = ty.numeric_min_val(self.tcx)?;
-                Some((
-                    mir::ConstantKind::from_bits(self.tcx, lo, ty::ParamEnv::empty().and(ty)),
-                    *hi,
-                ))
+                Some((ty::Const::from_bits(self.tcx, lo, ty::ParamEnv::empty().and(ty)), *hi))
             }
             _ => None,
         }
@@ -496,7 +490,7 @@ fn lower_path(&mut self, qpath: &hir::QPath<'_>, id: hir::HirId, span: Span) ->
 
         match self.tcx.const_eval_instance(param_env_reveal_all, instance, Some(span)) {
             Ok(value) => {
-                let const_ = mir::ConstantKind::Val(value, ty);
+                let const_ = ty::Const::from_value(self.tcx, value, ty);
                 let pattern = self.const_to_pat(const_, id, span, mir_structural_match_violation);
 
                 if !is_associated_const {
@@ -545,30 +539,25 @@ fn lower_inline_const(
         span: Span,
     ) -> PatKind<'tcx> {
         let anon_const_def_id = self.tcx.hir().local_def_id(anon_const.hir_id);
-        let value = mir::ConstantKind::from_inline_const(self.tcx, anon_const_def_id);
+        let value = ty::Const::from_inline_const(self.tcx, anon_const_def_id);
 
         // Evaluate early like we do in `lower_path`.
         let value = value.eval(self.tcx, self.param_env);
 
-        match value {
-            mir::ConstantKind::Ty(c) => {
-                match c.val() {
-                    ConstKind::Param(_) => {
-                        self.errors.push(PatternError::ConstParamInPattern(span));
-                        return PatKind::Wild;
-                    }
-                    ConstKind::Unevaluated(_) => {
-                        // If we land here it means the const can't be evaluated because it's `TooGeneric`.
-                        self.tcx
-                            .sess
-                            .span_err(span, "constant pattern depends on a generic parameter");
-                        return PatKind::Wild;
-                    }
-                    _ => bug!("Expected either ConstKind::Param or ConstKind::Unevaluated"),
-                }
+        match value.val() {
+            ConstKind::Param(_) => {
+                self.errors.push(PatternError::ConstParamInPattern(span));
+                return PatKind::Wild;
             }
-            mir::ConstantKind::Val(_, _) => *self.const_to_pat(value, id, span, false).kind,
+            ConstKind::Unevaluated(_) => {
+                // If we land here it means the const can't be evaluated because it's `TooGeneric`.
+                self.tcx.sess.span_err(span, "constant pattern depends on a generic parameter");
+                return PatKind::Wild;
+            }
+            _ => (),
         }
+
+        *self.const_to_pat(value, id, span, false).kind
     }
 
     /// Converts literals, paths and negation of literals to patterns.
@@ -595,7 +584,7 @@ fn lower_lit(&mut self, expr: &'tcx hir::Expr<'tcx>) -> PatKind<'tcx> {
 
         let lit_input =
             LitToConstInput { lit: &lit.node, ty: self.typeck_results.expr_ty(expr), neg };
-        match self.tcx.at(expr.span).lit_to_mir_constant(lit_input) {
+        match self.tcx.at(expr.span).lit_to_const(lit_input) {
             Ok(constant) => *self.const_to_pat(constant, expr.hir_id, lit.span, false).kind,
             Err(LitToConstError::Reported) => PatKind::Wild,
             Err(LitToConstError::TypeError) => bug!("lower_lit: had type error"),
@@ -750,11 +739,12 @@ fn super_fold_with<F: PatternFolder<'tcx>>(&self, folder: &mut F) -> Self {
     }
 }
 
+// FIXME: Get rid of this function once valtrees land
 #[instrument(skip(tcx), level = "debug")]
 crate fn compare_const_vals<'tcx>(
     tcx: TyCtxt<'tcx>,
-    a: mir::ConstantKind<'tcx>,
-    b: mir::ConstantKind<'tcx>,
+    a: ty::Const<'tcx>,
+    b: ty::Const<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     ty: Ty<'tcx>,
 ) -> Option<Ordering> {
diff --git a/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs b/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs
index 15bb5adf8ba19a2768836a0a11ce5f8397cc9f82..687b2e23c9fcb01cbf455addae52954f5a4955d2 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs
@@ -765,10 +765,7 @@ fn lint_non_exhaustive_omitted_patterns<'p, 'tcx>(
 /// `is_under_guard` is used to inform if the pattern has a guard. If it
 /// has one it must not be inserted into the matrix. This shouldn't be
 /// relied on for soundness.
-#[instrument(
-    level = "debug",
-    skip(cx, matrix, witness_preference, hir_id, is_under_guard, is_top_level)
-)]
+#[instrument(level = "debug", skip(cx, matrix, hir_id))]
 fn is_useful<'p, 'tcx>(
     cx: &MatchCheckCtxt<'p, 'tcx>,
     matrix: &Matrix<'p, 'tcx>,
@@ -800,6 +797,7 @@ fn is_useful<'p, 'tcx>(
 
     let ty = v.head().ty();
     let is_non_exhaustive = cx.is_foreign_non_exhaustive_enum(ty);
+    debug!("v.head: {:?}, v.span: {:?}", v.head(), v.head().span());
     let pcx = PatCtxt { cx, ty, span: v.head().span(), is_top_level, is_non_exhaustive };
 
     // If the first pattern is an or-pattern, expand it.
@@ -809,9 +807,11 @@ fn is_useful<'p, 'tcx>(
         // We try each or-pattern branch in turn.
         let mut matrix = matrix.clone();
         for v in v.expand_or_pat() {
+            debug!(?v);
             let usefulness = ensure_sufficient_stack(|| {
                 is_useful(cx, &matrix, &v, witness_preference, hir_id, is_under_guard, false)
             });
+            debug!(?usefulness);
             ret.extend(usefulness);
             // If pattern has a guard don't add it to the matrix.
             if !is_under_guard {
@@ -822,6 +822,7 @@ fn is_useful<'p, 'tcx>(
         }
     } else {
         let v_ctor = v.head().ctor();
+        debug!(?v_ctor);
         if let Constructor::IntRange(ctor_range) = &v_ctor {
             // Lint on likely incorrect range patterns (#63987)
             ctor_range.lint_overlapping_range_endpoints(
@@ -895,7 +896,7 @@ fn is_useful<'p, 'tcx>(
 }
 
 /// The arm of a match expression.
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, Debug)]
 crate struct MatchArm<'p, 'tcx> {
     /// The pattern must have been lowered through `check_match::MatchVisitor::lower_pattern`.
     crate pat: &'p DeconstructedPat<'p, 'tcx>,
@@ -928,6 +929,7 @@ fn is_useful<'p, 'tcx>(
 ///
 /// Note: the input patterns must have been lowered through
 /// `check_match::MatchVisitor::lower_pattern`.
+#[instrument(skip(cx, arms), level = "debug")]
 crate fn compute_match_usefulness<'p, 'tcx>(
     cx: &MatchCheckCtxt<'p, 'tcx>,
     arms: &[MatchArm<'p, 'tcx>],
@@ -939,6 +941,7 @@ fn is_useful<'p, 'tcx>(
         .iter()
         .copied()
         .map(|arm| {
+            debug!(?arm);
             let v = PatStack::from_pattern(arm.pat);
             is_useful(cx, &matrix, &v, RealArm, arm.hir_id, arm.has_guard, true);
             if !arm.has_guard {
diff --git a/compiler/rustc_privacy/src/lib.rs b/compiler/rustc_privacy/src/lib.rs
index 47af6bae6bb2779d9b3fadd002ae8c6633303b5e..0ce97de413496db7146557dd8e4681183a3acbb6 100644
--- a/compiler/rustc_privacy/src/lib.rs
+++ b/compiler/rustc_privacy/src/lib.rs
@@ -19,7 +19,6 @@
 use rustc_middle::bug;
 use rustc_middle::hir::nested_filter;
 use rustc_middle::middle::privacy::{AccessLevel, AccessLevels};
-use rustc_middle::mir::ConstantKind;
 use rustc_middle::span_bug;
 use rustc_middle::thir::abstract_const::Node as ACNode;
 use rustc_middle::ty::fold::TypeVisitor;
@@ -157,10 +156,7 @@ fn visit_abstract_const_expr(
         ct: AbstractConst<'tcx>,
     ) -> ControlFlow<V::BreakTy> {
         const_evaluatable::walk_abstract_const(tcx, ct, |node| match node.root(tcx) {
-            ACNode::Leaf(leaf) => match leaf {
-                ConstantKind::Ty(c) => self.visit_const(c),
-                ConstantKind::Val(_, ty) => self.visit_ty(ty),
-            },
+            ACNode::Leaf(leaf) => self.visit_const(leaf),
             ACNode::Cast(_, _, ty) => self.visit_ty(ty),
             ACNode::Binop(..) | ACNode::UnaryOp(..) | ACNode::FunctionCall(_, _) => {
                 ControlFlow::CONTINUE
@@ -288,7 +284,7 @@ fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<V::BreakTy> {
     fn visit_const(&mut self, c: Const<'tcx>) -> ControlFlow<Self::BreakTy> {
         self.visit_ty(c.ty())?;
         let tcx = self.def_id_visitor.tcx();
-        if let Ok(Some(ct)) = AbstractConst::from_constant(tcx, ConstantKind::Ty(c)) {
+        if let Ok(Some(ct)) = AbstractConst::from_const(tcx, c) {
             self.visit_abstract_const_expr(tcx, ct)?;
         }
         ControlFlow::CONTINUE
diff --git a/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs b/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
index cdec38db12495a13ea7b52cca22036ef5b20a635..709dd346efcc5203ce4f68996a29af983e3f3ecf 100644
--- a/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
+++ b/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
@@ -37,14 +37,9 @@ pub fn is_const_evaluatable<'cx, 'tcx>(
     param_env: ty::ParamEnv<'tcx>,
     span: Span,
 ) -> Result<(), NotConstEvaluatable> {
-<<<<<<< HEAD
     let tcx = infcx.tcx;
 
     if tcx.features().generic_const_exprs {
-=======
-    if infcx.tcx.features().generic_const_exprs {
-        let tcx = infcx.tcx;
->>>>>>> 6064f16d846 (change thir to use mir::ConstantKind instead of ty::Const)
         match AbstractConst::new(tcx, uv)? {
             // We are looking at a generic abstract constant.
             Some(ct) => {
@@ -249,7 +244,7 @@ pub fn new(
         Ok(inner.map(|inner| AbstractConst { inner, substs: uv.substs }))
     }
 
-    pub fn from_constant(
+    pub fn from_const(
         tcx: TyCtxt<'tcx>,
         ct: ty::Const<'tcx>,
     ) -> Result<Option<AbstractConst<'tcx>>, ErrorGuaranteed> {
@@ -382,6 +377,10 @@ fn visit_pat(&mut self, pat: &thir::Pat<'tcx>) {
                 }
             }
 
+            fn visit_const(&mut self, ct: ty::Const<'tcx>) {
+                self.is_poly |= ct.has_param_types_or_consts();
+            }
+
             fn visit_constant(&mut self, ct: mir::ConstantKind<'tcx>) {
                 self.is_poly |= ct.has_param_types_or_consts();
             }
@@ -423,10 +422,10 @@ fn build(mut self) -> Result<&'tcx [Node<'tcx>], ErrorGuaranteed> {
         self.recurse_build(self.body_id)?;
 
         for n in self.nodes.iter() {
-            if let Node::Leaf(mir::ConstantKind::Ty(ty::Const(Interned(
+            if let Node::Leaf(ty::Const(Interned(
                 ty::ConstS { val: ty::ConstKind::Unevaluated(ct), ty: _ },
                 _,
-            )))) = n
+            ))) = n
             {
                 // `AbstractConst`s should not contain any promoteds as they require references which
                 // are not allowed.
@@ -863,4 +862,4 @@ fn try_unify(&self, a: AbstractConst<'tcx>, b: AbstractConst<'tcx>) -> bool {
                     false
 >>>>>>> 6064f16d846 (change thir to use mir::ConstantKind instead of ty::Const)
 
- */
\ No newline at end of file
+ */
diff --git a/compiler/rustc_trait_selection/src/traits/object_safety.rs b/compiler/rustc_trait_selection/src/traits/object_safety.rs
index 67f153e0abdd7822207ac53d47da3a4c8f39cc7d..6cceec8621304cf3e5db3a449be8dfde588f15f6 100644
--- a/compiler/rustc_trait_selection/src/traits/object_safety.rs
+++ b/compiler/rustc_trait_selection/src/traits/object_safety.rs
@@ -17,7 +17,6 @@
 use rustc_errors::FatalError;
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
-use rustc_middle::mir::ConstantKind;
 use rustc_middle::ty::subst::{GenericArg, InternalSubsts, Subst};
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable, TypeVisitor};
 use rustc_middle::ty::{Predicate, ToPredicate};
@@ -837,10 +836,7 @@ fn visit_unevaluated_const(
             if let Ok(Some(ct)) = AbstractConst::new(self.tcx, uv.shrink()) {
                 const_evaluatable::walk_abstract_const(self.tcx, ct, |node| {
                     match node.root(self.tcx) {
-                        Node::Leaf(leaf) => match leaf {
-                            ConstantKind::Ty(c) => self.visit_const(c),
-                            ConstantKind::Val(_, ty) => self.visit_ty(ty),
-                        },
+                        Node::Leaf(leaf) => self.visit_const(leaf),
                         Node::Cast(_, _, ty) => self.visit_ty(ty),
                         Node::Binop(..) | Node::UnaryOp(..) | Node::FunctionCall(_, _) => {
                             ControlFlow::CONTINUE