diff --git a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
index 7f0d6c8e8734..62ec0d2ef8bf 100644
--- a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
+++ b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
@@ -8,7 +8,7 @@
 use rustc_middle::query::TyCtxtAt;
 use rustc_middle::ty::layout::{HasTypingEnv, TyAndLayout};
 use rustc_middle::ty::print::with_no_trimmed_paths;
-use rustc_middle::ty::{self, MayBeErased, Ty, TyCtxt};
+use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_middle::{bug, throw_inval};
 use rustc_span::Span;
 use rustc_span::def_id::LocalDefId;
@@ -374,7 +374,7 @@ pub fn eval_to_allocation_raw_provider<'tcx>(
     assert!(key.value.promoted.is_some() || !tcx.is_static(key.value.instance.def_id()));
 
     if cfg!(debug_assertions) {
-        match key.typing_env.typing_mode() {
+        match key.typing_env.typing_mode().assert_not_erased() {
             ty::TypingMode::PostAnalysis => {}
             ty::TypingMode::Coherence
             | ty::TypingMode::Analysis { .. }
@@ -384,7 +384,6 @@ pub fn eval_to_allocation_raw_provider<'tcx>(
                     "Const eval should always happens in PostAnalysis mode. See the comment in `InterpCx::new` for more details."
                 )
             }
-            ty::TypingMode::ErasedNotCoherence(MayBeErased) => todo!(),
         }
 
         // Make sure we format the instance even if we do not print it.
diff --git a/compiler/rustc_const_eval/src/const_eval/valtrees.rs b/compiler/rustc_const_eval/src/const_eval/valtrees.rs
index 3858a3b7047d..0169dc7ed99d 100644
--- a/compiler/rustc_const_eval/src/const_eval/valtrees.rs
+++ b/compiler/rustc_const_eval/src/const_eval/valtrees.rs
@@ -3,7 +3,7 @@
 use rustc_middle::mir::interpret::{EvalToValTreeResult, GlobalId, ValTreeCreationError};
 use rustc_middle::traits::ObligationCause;
 use rustc_middle::ty::layout::{LayoutCx, TyAndLayout};
-use rustc_middle::ty::{self, MayBeErased, Ty, TyCtxt};
+use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_middle::{bug, mir};
 use rustc_span::DUMMY_SP;
 use tracing::{debug, instrument, trace};
@@ -237,7 +237,7 @@ pub(crate) fn eval_to_valtree<'tcx>(
     cid: GlobalId<'tcx>,
 ) -> EvalToValTreeResult<'tcx> {
     if cfg!(debug_assertions) {
-        match typing_env.typing_mode() {
+        match typing_env.typing_mode().assert_not_erased() {
             ty::TypingMode::PostAnalysis => {}
             ty::TypingMode::Coherence
             | ty::TypingMode::Analysis { .. }
@@ -247,7 +247,6 @@ pub(crate) fn eval_to_valtree<'tcx>(
                     "Const eval should always happens in PostAnalysis mode. See the comment in `InterpCx::new` for more details."
                 )
             }
-            ty::TypingMode::ErasedNotCoherence(MayBeErased) => unreachable!(),
         }
     }
     let const_alloc = tcx.eval_to_allocation_raw(typing_env.as_query_input(cid))?;
diff --git a/compiler/rustc_const_eval/src/interpret/eval_context.rs b/compiler/rustc_const_eval/src/interpret/eval_context.rs
index 06410df7e1f1..7dc6d292a94a 100644
--- a/compiler/rustc_const_eval/src/interpret/eval_context.rs
+++ b/compiler/rustc_const_eval/src/interpret/eval_context.rs
@@ -9,8 +9,8 @@
     LayoutOfHelpers, TyAndLayout,
 };
 use rustc_middle::ty::{
-    self, GenericArgsRef, MayBeErased, Ty, TyCtxt, TypeFoldable, TypeVisitableExt, TypingEnv,
-    TypingMode, Variance,
+    self, GenericArgsRef, Ty, TyCtxt, TypeFoldable, TypeVisitableExt, TypingEnv, TypingMode,
+    Variance,
 };
 use rustc_middle::{bug, mir, span_bug};
 use rustc_span::Span;
@@ -243,7 +243,7 @@ pub fn new(
         // types that are not specified in the opaque type. We also use MIR bodies whose opaque types have
         // already been revealed, so we'd be able to at least partially observe the hidden types anyways.
         if cfg!(debug_assertions) {
-            match typing_env.typing_mode() {
+            match typing_env.typing_mode().assert_not_erased() {
                 TypingMode::PostAnalysis => {}
                 TypingMode::Coherence
                 | TypingMode::Analysis { .. }
@@ -251,7 +251,6 @@ pub fn new(
                 | TypingMode::PostBorrowckAnalysis { .. } => {
                     bug!("Const eval should always happens in PostAnalysis mode.");
                 }
-                TypingMode::ErasedNotCoherence(MayBeErased) => unreachable!(),
             }
         }
 
diff --git a/compiler/rustc_mir_transform/src/elaborate_drop.rs b/compiler/rustc_mir_transform/src/elaborate_drop.rs
index 48006bace447..6cd08cafbcc1 100644
--- a/compiler/rustc_mir_transform/src/elaborate_drop.rs
+++ b/compiler/rustc_mir_transform/src/elaborate_drop.rs
@@ -7,7 +7,7 @@
 use rustc_middle::mir::*;
 use rustc_middle::ty::adjustment::PointerCoercion;
 use rustc_middle::ty::util::IntTypeExt;
-use rustc_middle::ty::{self, GenericArg, GenericArgsRef, MayBeErased, Ty, TyCtxt, Unnormalized};
+use rustc_middle::ty::{self, GenericArg, GenericArgsRef, Ty, TyCtxt, Unnormalized};
 use rustc_middle::{bug, span_bug, traits};
 use rustc_span::{DUMMY_SP, Spanned, dummy_spanned};
 use tracing::{debug, instrument};
@@ -547,7 +547,7 @@ fn move_paths_for_fields(
                 let subpath = self.elaborator.field_subpath(variant_path, field_idx);
                 let tcx = self.tcx();
 
-                match self.elaborator.typing_env().typing_mode() {
+                match self.elaborator.typing_env().typing_mode().assert_not_erased() {
                     ty::TypingMode::PostAnalysis => {}
                     ty::TypingMode::Coherence
                     | ty::TypingMode::Analysis { .. }
@@ -555,7 +555,6 @@ fn move_paths_for_fields(
                     | ty::TypingMode::PostBorrowckAnalysis { .. } => {
                         bug!()
                     }
-                    ty::TypingMode::ErasedNotCoherence(MayBeErased) => unreachable!(),
                 }
 
                 let field_ty = field.ty(tcx, args);
diff --git a/compiler/rustc_next_trait_solver/src/solve/mod.rs b/compiler/rustc_next_trait_solver/src/solve/mod.rs
index 678cf2f9abe6..178a192a6630 100644
--- a/compiler/rustc_next_trait_solver/src/solve/mod.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/mod.rs
@@ -24,7 +24,7 @@
 use derive_where::derive_where;
 use rustc_type_ir::inherent::*;
 pub use rustc_type_ir::solve::*;
-use rustc_type_ir::{self as ty, Interner, MayBeErased, TyVid, TypingMode};
+use rustc_type_ir::{self as ty, Interner, TyVid, TypingMode};
 use tracing::instrument;
 
 pub use self::eval_ctxt::{
@@ -358,7 +358,11 @@ fn structurally_normalize_term(
     }
 
     fn opaque_type_is_rigid(&self, def_id: I::DefId) -> bool {
-        match self.typing_mode() {
+        match self
+            .typing_mode()
+            // Caller should handle erased mode
+            .assert_not_erased()
+        {
             // Opaques are never rigid outside of analysis mode.
             TypingMode::Coherence | TypingMode::PostAnalysis => false,
             // During analysis, opaques are rigid unless they may be defined by
@@ -368,8 +372,6 @@ fn opaque_type_is_rigid(&self, def_id: I::DefId) -> bool {
             | TypingMode::PostBorrowckAnalysis { defined_opaque_types: non_rigid_opaques } => {
                 !def_id.as_local().is_some_and(|def_id| non_rigid_opaques.contains(&def_id))
             }
-            // Caller should handle this variant
-            TypingMode::ErasedNotCoherence(MayBeErased) => unreachable!(),
         }
     }
 }
diff --git a/compiler/rustc_next_trait_solver/src/solve/normalizes_to/mod.rs b/compiler/rustc_next_trait_solver/src/solve/normalizes_to/mod.rs
index 7996e9a44878..632311ebab1b 100644
--- a/compiler/rustc_next_trait_solver/src/solve/normalizes_to/mod.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/normalizes_to/mod.rs
@@ -8,8 +8,7 @@
 use rustc_type_ir::lang_items::{SolverAdtLangItem, SolverLangItem, SolverTraitLangItem};
 use rustc_type_ir::solve::{FetchEligibleAssocItemResponse, RerunReason};
 use rustc_type_ir::{
-    self as ty, FieldInfo, Interner, MayBeErased, NormalizesTo, PredicateKind, Unnormalized,
-    Upcast as _,
+    self as ty, FieldInfo, Interner, NormalizesTo, PredicateKind, Unnormalized, Upcast as _,
 };
 use tracing::instrument;
 
diff --git a/compiler/rustc_next_trait_solver/src/solve/normalizes_to/opaque_types.rs b/compiler/rustc_next_trait_solver/src/solve/normalizes_to/opaque_types.rs
index 83d078c5d873..45dd2f25abd7 100644
--- a/compiler/rustc_next_trait_solver/src/solve/normalizes_to/opaque_types.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/normalizes_to/opaque_types.rs
@@ -82,7 +82,7 @@ pub(super) fn normalize_opaque_type(
                     // During HIR typeck, opaque types start out as unconstrained
                     // inference variables. In borrowck we instead use the type
                     // computed in HIR typeck as the initial value.
-                    match self.typing_mode() {
+                    match self.typing_mode().assert_not_erased() {
                         TypingMode::Analysis { .. } => {}
                         TypingMode::Borrowck { .. } => {
                             let actual = cx
@@ -98,7 +98,6 @@ pub(super) fn normalize_opaque_type(
                         TypingMode::Coherence
                         | TypingMode::PostBorrowckAnalysis { .. }
                         | TypingMode::PostAnalysis => unreachable!(),
-                        TypingMode::ErasedNotCoherence(MayBeErased) => todo!(),
                     }
                 }
 
diff --git a/compiler/rustc_trait_selection/src/traits/normalize.rs b/compiler/rustc_trait_selection/src/traits/normalize.rs
index 6e526e8dc548..84dbd53de83f 100644
--- a/compiler/rustc_trait_selection/src/traits/normalize.rs
+++ b/compiler/rustc_trait_selection/src/traits/normalize.rs
@@ -12,8 +12,8 @@
 use rustc_middle::span_bug;
 use rustc_middle::traits::{ObligationCause, ObligationCauseCode};
 use rustc_middle::ty::{
-    self, AliasTerm, MayBeErased, Term, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable,
-    TypeVisitable, TypeVisitableExt, TypingMode, Unnormalized,
+    self, AliasTerm, Term, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable, TypeVisitable,
+    TypeVisitableExt, TypingMode, Unnormalized,
 };
 use tracing::{debug, instrument};
 
@@ -138,14 +138,13 @@ pub(super) fn needs_normalization<'tcx, T: TypeVisitable<TyCtxt<'tcx>>>(
 
     // Opaques are treated as rigid outside of `TypingMode::PostAnalysis`,
     // so we can ignore those.
-    match infcx.typing_mode_raw() {
+    match infcx.typing_mode_raw().assert_not_erased() {
         // FIXME(#132279): We likely want to reveal opaques during post borrowck analysis
         TypingMode::Coherence
         | TypingMode::Analysis { .. }
         | TypingMode::Borrowck { .. }
         | TypingMode::PostBorrowckAnalysis { .. } => flags.remove(ty::TypeFlags::HAS_TY_OPAQUE),
         TypingMode::PostAnalysis => {}
-        TypingMode::ErasedNotCoherence(MayBeErased) => unreachable!(),
     }
 
     value.has_type_flags(flags)
diff --git a/compiler/rustc_ty_utils/src/instance.rs b/compiler/rustc_ty_utils/src/instance.rs
index 178533fb231a..c423f9925c6b 100644
--- a/compiler/rustc_ty_utils/src/instance.rs
+++ b/compiler/rustc_ty_utils/src/instance.rs
@@ -6,8 +6,8 @@
 use rustc_middle::query::Providers;
 use rustc_middle::traits::{BuiltinImplSource, CodegenObligationError};
 use rustc_middle::ty::{
-    self, ClosureKind, GenericArgsRef, Instance, MayBeErased, PseudoCanonicalInput, TyCtxt,
-    TypeVisitableExt, Unnormalized,
+    self, ClosureKind, GenericArgsRef, Instance, PseudoCanonicalInput, TyCtxt, TypeVisitableExt,
+    Unnormalized,
 };
 use rustc_span::sym;
 use rustc_trait_selection::traits;
@@ -155,13 +155,12 @@ fn resolve_associated_item<'tcx>(
                 // and the obligation is monomorphic, otherwise passes such as
                 // transmute checking and polymorphic MIR optimizations could
                 // get a result which isn't correct for all monomorphizations.
-                match typing_env.typing_mode() {
+                match typing_env.typing_mode().assert_not_erased() {
                     ty::TypingMode::Coherence
                     | ty::TypingMode::Analysis { .. }
                     | ty::TypingMode::Borrowck { .. }
                     | ty::TypingMode::PostBorrowckAnalysis { .. } => false,
                     ty::TypingMode::PostAnalysis => !trait_ref.still_further_specializable(),
-                    ty::TypingMode::ErasedNotCoherence(MayBeErased) => unreachable!(),
                 }
             };
             if !eligible {