diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
index 62013958c7e5..4cdfc752d989 100644
--- a/compiler/rustc_hir/src/hir.rs
+++ b/compiler/rustc_hir/src/hir.rs
@@ -3065,7 +3065,7 @@ macro_rules! expect_methods_self_kind {
         $(
             #[track_caller]
             pub fn $name(&self) -> $ret_ty {
-                let $pat = &self.kind else { expect_failed(stringify!($ident), self) };
+                let $pat = &self.kind else { expect_failed(stringify!($name), self) };
                 $ret_val
             }
         )*
@@ -3077,7 +3077,7 @@ macro_rules! expect_methods_self {
         $(
             #[track_caller]
             pub fn $name(&self) -> $ret_ty {
-                let $pat = self else { expect_failed(stringify!($ident), self) };
+                let $pat = self else { expect_failed(stringify!($name), self) };
                 $ret_val
             }
         )*
@@ -4790,6 +4790,11 @@ impl<'hir> Node<'hir> {
                 ForeignItemKind::Static(ty, ..) => Some(ty),
                 _ => None,
             },
+            Node::GenericParam(param) => match param.kind {
+                GenericParamKind::Lifetime { .. } => None,
+                GenericParamKind::Type { default, .. } => default,
+                GenericParamKind::Const { ty, .. } => Some(ty),
+            },
             _ => None,
         }
     }
diff --git a/compiler/rustc_hir_analysis/src/check/check.rs b/compiler/rustc_hir_analysis/src/check/check.rs
index f58808f903b0..7fa8f9563622 100644
--- a/compiler/rustc_hir_analysis/src/check/check.rs
+++ b/compiler/rustc_hir_analysis/src/check/check.rs
@@ -918,7 +918,10 @@ pub(crate) fn check_item_type(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Result<(),
                 );
                 check_where_clauses(wfcx, def_id);
 
-                wfcheck::check_const_item_rhs(wfcx, def_id)
+                if find_attr!(tcx.get_all_attrs(def_id), AttributeKind::TypeConst(_)) {
+                    wfcheck::check_type_const(wfcx, def_id, ty, true)?;
+                }
+                Ok(())
             }));
 
             // Only `Node::Item` and `Node::ForeignItem` still have HIR based
diff --git a/compiler/rustc_hir_analysis/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
index 82b708cc5ee9..ccae524352a5 100644
--- a/compiler/rustc_hir_analysis/src/check/wfcheck.rs
+++ b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
@@ -951,7 +951,12 @@ pub(crate) fn check_associated_item(
                 let ty = wfcx.deeply_normalize(span, Some(WellFormedLoc::Ty(def_id)), ty);
                 wfcx.register_wf_obligation(span, loc, ty.into());
 
-                if item.defaultness(tcx).has_value() {
+                let has_value = item.defaultness(tcx).has_value();
+                if find_attr!(tcx.get_all_attrs(def_id), AttributeKind::TypeConst(_)) {
+                    check_type_const(wfcx, def_id, ty, has_value)?;
+                }
+
+                if has_value {
                     let code = ObligationCauseCode::SizedConstOrStatic;
                     wfcx.register_bound(
                         ObligationCause::new(span, def_id, code),
@@ -959,8 +964,6 @@ pub(crate) fn check_associated_item(
                         ty,
                         tcx.require_lang_item(LangItem::Sized, span),
                     );
-
-                    check_const_item_rhs(wfcx, def_id)?;
                 }
 
                 Ok(())
@@ -1230,16 +1233,33 @@ pub(crate) fn check_static_item<'tcx>(
 }
 
 #[instrument(level = "debug", skip(wfcx))]
-pub(super) fn check_const_item_rhs<'tcx>(
+pub(super) fn check_type_const<'tcx>(
     wfcx: &WfCheckingCtxt<'_, 'tcx>,
     def_id: LocalDefId,
+    item_ty: Ty<'tcx>,
+    has_value: bool,
 ) -> Result<(), ErrorGuaranteed> {
     let tcx = wfcx.tcx();
-    if find_attr!(tcx.get_all_attrs(def_id), AttributeKind::TypeConst(_)) {
+    let span = tcx.def_span(def_id);
+
+    wfcx.register_bound(
+        ObligationCause::new(span, def_id, ObligationCauseCode::ConstParam(item_ty)),
+        wfcx.param_env,
+        item_ty,
+        tcx.require_lang_item(LangItem::ConstParamTy, span),
+    );
+
+    if has_value {
         let raw_ct = tcx.const_of_item(def_id).instantiate_identity();
-        let span = tcx.def_span(def_id);
         let norm_ct = wfcx.deeply_normalize(span, Some(WellFormedLoc::Ty(def_id)), raw_ct);
         wfcx.register_wf_obligation(span, Some(WellFormedLoc::Ty(def_id)), norm_ct.into());
+
+        wfcx.register_obligation(Obligation::new(
+            tcx,
+            ObligationCause::new(span, def_id, ObligationCauseCode::WellFormed(None)),
+            wfcx.param_env,
+            ty::PredicateKind::Clause(ty::ClauseKind::ConstArgHasType(norm_ct, item_ty)),
+        ));
     }
     Ok(())
 }
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 d2f2c92dda08..c282f4204260 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
@@ -1286,12 +1286,8 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         ty: Ty<'tcx>,
         obligation: &PredicateObligation<'tcx>,
     ) -> Diag<'a> {
-        let param = obligation.cause.body_id;
-        let hir::GenericParamKind::Const { ty: &hir::Ty { span, .. }, .. } =
-            self.tcx.hir_node_by_def_id(param).expect_generic_param().kind
-        else {
-            bug!()
-        };
+        let def_id = obligation.cause.body_id;
+        let span = self.tcx.ty_span(def_id);
 
         let mut file = None;
         let ty_str = self.tcx.short_string(ty, &mut file);
diff --git a/tests/ui/associated-consts/assoc-const-eq-ambiguity.rs b/tests/ui/associated-consts/assoc-const-eq-ambiguity.rs
index d433af6bdd57..2ff5a0353a0a 100644
--- a/tests/ui/associated-consts/assoc-const-eq-ambiguity.rs
+++ b/tests/ui/associated-consts/assoc-const-eq-ambiguity.rs
@@ -1,7 +1,7 @@
 // We used to say "ambiguous associated type" on ambiguous associated consts.
 // Ensure that we now use the correct label.
 
-#![feature(associated_const_equality, min_generic_const_args)]
+#![feature(associated_const_equality, min_generic_const_args, unsized_const_params)]
 #![allow(incomplete_features)]
 
 trait Trait0: Parent0<i32> + Parent0<u32> {}
diff --git a/tests/ui/associated-consts/assoc-const-eq-bound-var-in-ty-not-wf.rs b/tests/ui/associated-consts/assoc-const-eq-bound-var-in-ty-not-wf.rs
index f6240ead0b9b..5232b895803e 100644
--- a/tests/ui/associated-consts/assoc-const-eq-bound-var-in-ty-not-wf.rs
+++ b/tests/ui/associated-consts/assoc-const-eq-bound-var-in-ty-not-wf.rs
@@ -1,9 +1,16 @@
 // Check that we eventually catch types of assoc const bounds
 // (containing late-bound vars) that are ill-formed.
-#![feature(associated_const_equality, min_generic_const_args)]
+#![feature(
+    associated_const_equality,
+    min_generic_const_args,
+    adt_const_params,
+    unsized_const_params,
+)]
 #![allow(incomplete_features)]
 
-trait Trait<T> {
+use std::marker::ConstParamTy_;
+
+trait Trait<T: ConstParamTy_> {
     #[type_const]
     const K: T;
 }
diff --git a/tests/ui/associated-consts/assoc-const-eq-bound-var-in-ty-not-wf.stderr b/tests/ui/associated-consts/assoc-const-eq-bound-var-in-ty-not-wf.stderr
index b629bb4d3f8c..a0329e2b15d1 100644
--- a/tests/ui/associated-consts/assoc-const-eq-bound-var-in-ty-not-wf.stderr
+++ b/tests/ui/associated-consts/assoc-const-eq-bound-var-in-ty-not-wf.stderr
@@ -1,11 +1,11 @@
 error: higher-ranked subtype error
-  --> $DIR/assoc-const-eq-bound-var-in-ty-not-wf.rs:14:13
+  --> $DIR/assoc-const-eq-bound-var-in-ty-not-wf.rs:21:13
    |
 LL |         K = { () }
    |             ^^^^^^
 
 error: higher-ranked subtype error
-  --> $DIR/assoc-const-eq-bound-var-in-ty-not-wf.rs:14:13
+  --> $DIR/assoc-const-eq-bound-var-in-ty-not-wf.rs:21:13
    |
 LL |         K = { () }
    |             ^^^^^^
@@ -13,7 +13,7 @@ LL |         K = { () }
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error: implementation of `Project` is not general enough
-  --> $DIR/assoc-const-eq-bound-var-in-ty-not-wf.rs:12:13
+  --> $DIR/assoc-const-eq-bound-var-in-ty-not-wf.rs:19:13
    |
 LL |       _: impl Trait<
    |  _____________^
diff --git a/tests/ui/associated-consts/assoc-const-eq-bound-var-in-ty.rs b/tests/ui/associated-consts/assoc-const-eq-bound-var-in-ty.rs
index 36b3d8a648fd..ef8077b9f44a 100644
--- a/tests/ui/associated-consts/assoc-const-eq-bound-var-in-ty.rs
+++ b/tests/ui/associated-consts/assoc-const-eq-bound-var-in-ty.rs
@@ -3,10 +3,17 @@
 //
 //@ check-pass
 
-#![feature(associated_const_equality, min_generic_const_args)]
+#![feature(
+    associated_const_equality,
+    min_generic_const_args,
+    adt_const_params,
+    unsized_const_params,
+)]
 #![allow(incomplete_features)]
 
-trait Trait<T> {
+use std::marker::ConstParamTy_;
+
+trait Trait<T: ConstParamTy_> {
     #[type_const]
     const K: T;
 }
diff --git a/tests/ui/associated-consts/assoc-const-eq-esc-bound-var-in-ty.rs b/tests/ui/associated-consts/assoc-const-eq-esc-bound-var-in-ty.rs
index 3f48b3bfbb6d..1ab93ea596a7 100644
--- a/tests/ui/associated-consts/assoc-const-eq-esc-bound-var-in-ty.rs
+++ b/tests/ui/associated-consts/assoc-const-eq-esc-bound-var-in-ty.rs
@@ -1,6 +1,6 @@
 // Detect and reject escaping late-bound generic params in
 // the type of assoc consts used in an equality bound.
-#![feature(associated_const_equality, min_generic_const_args)]
+#![feature(associated_const_equality, min_generic_const_args, unsized_const_params)]
 #![allow(incomplete_features)]
 
 trait Trait<'a> {
diff --git a/tests/ui/associated-consts/assoc-const-eq-param-in-ty.rs b/tests/ui/associated-consts/assoc-const-eq-param-in-ty.rs
index 5b0438e95695..0afb95a0b033 100644
--- a/tests/ui/associated-consts/assoc-const-eq-param-in-ty.rs
+++ b/tests/ui/associated-consts/assoc-const-eq-param-in-ty.rs
@@ -1,14 +1,21 @@
 // Regression test for issue #108271.
 // Detect and reject generic params in the type of assoc consts used in an equality bound.
-#![feature(associated_const_equality, min_generic_const_args)]
+#![feature(
+    associated_const_equality,
+    min_generic_const_args,
+    adt_const_params,
+    unsized_const_params,
+)]
 #![allow(incomplete_features)]
 
-trait Trait<'a, T: 'a, const N: usize> {
+use std::marker::ConstParamTy_;
+
+trait Trait<'a, T: 'a + ConstParamTy_, const N: usize> {
     #[type_const]
     const K: &'a [T; N];
 }
 
-fn take0<'r, A: 'r, const Q: usize>(_: impl Trait<'r, A, Q, K = { loop {} }>) {}
+fn take0<'r, A: 'r + ConstParamTy_, const Q: usize>(_: impl Trait<'r, A, Q, K = { loop {} }>) {}
 //~^ ERROR the type of the associated constant `K` must not depend on generic parameters
 //~| NOTE its type must not depend on the lifetime parameter `'r`
 //~| NOTE the lifetime parameter `'r` is defined here
@@ -22,7 +29,7 @@ fn take0<'r, A: 'r, const Q: usize>(_: impl Trait<'r, A, Q, K = { loop {} }>) {}
 //~| NOTE the const parameter `Q` is defined here
 //~| NOTE `K` has type `&'r [A; Q]`
 
-trait Project {
+trait Project: ConstParamTy_ {
     #[type_const]
     const SELF: Self;
 }
@@ -38,7 +45,7 @@ fn take2<P: Project<SELF = {}>>(_: P) {}
 //~| NOTE the type parameter `P` is defined here
 //~| NOTE `SELF` has type `P`
 
-trait Iface<'r> {
+trait Iface<'r>: ConstParamTy_ {
     //~^ NOTE the lifetime parameter `'r` is defined here
     //~| NOTE the lifetime parameter `'r` is defined here
     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
diff --git a/tests/ui/associated-consts/assoc-const-eq-param-in-ty.stderr b/tests/ui/associated-consts/assoc-const-eq-param-in-ty.stderr
index 7ba1d638baa8..229dd10c0beb 100644
--- a/tests/ui/associated-consts/assoc-const-eq-param-in-ty.stderr
+++ b/tests/ui/associated-consts/assoc-const-eq-param-in-ty.stderr
@@ -1,31 +1,31 @@
 error: the type of the associated constant `K` must not depend on generic parameters
-  --> $DIR/assoc-const-eq-param-in-ty.rs:11:61
+  --> $DIR/assoc-const-eq-param-in-ty.rs:18:77
    |
-LL | fn take0<'r, A: 'r, const Q: usize>(_: impl Trait<'r, A, Q, K = { loop {} }>) {}
-   |          -- the lifetime parameter `'r` is defined here     ^ its type must not depend on the lifetime parameter `'r`
+LL | fn take0<'r, A: 'r + ConstParamTy_, const Q: usize>(_: impl Trait<'r, A, Q, K = { loop {} }>) {}
+   |          -- the lifetime parameter `'r` is defined here                     ^ its type must not depend on the lifetime parameter `'r`
    |
    = note: `K` has type `&'r [A; Q]`
 
 error: the type of the associated constant `K` must not depend on generic parameters
-  --> $DIR/assoc-const-eq-param-in-ty.rs:11:61
+  --> $DIR/assoc-const-eq-param-in-ty.rs:18:77
    |
-LL | fn take0<'r, A: 'r, const Q: usize>(_: impl Trait<'r, A, Q, K = { loop {} }>) {}
-   |              - the type parameter `A` is defined here       ^ its type must not depend on the type parameter `A`
+LL | fn take0<'r, A: 'r + ConstParamTy_, const Q: usize>(_: impl Trait<'r, A, Q, K = { loop {} }>) {}
+   |              - the type parameter `A` is defined here                       ^ its type must not depend on the type parameter `A`
    |
    = note: `K` has type `&'r [A; Q]`
 
 error: the type of the associated constant `K` must not depend on generic parameters
-  --> $DIR/assoc-const-eq-param-in-ty.rs:11:61
+  --> $DIR/assoc-const-eq-param-in-ty.rs:18:77
    |
-LL | fn take0<'r, A: 'r, const Q: usize>(_: impl Trait<'r, A, Q, K = { loop {} }>) {}
-   |                           -                                 ^ its type must not depend on the const parameter `Q`
-   |                           |
-   |                           the const parameter `Q` is defined here
+LL | fn take0<'r, A: 'r + ConstParamTy_, const Q: usize>(_: impl Trait<'r, A, Q, K = { loop {} }>) {}
+   |                                           -                                 ^ its type must not depend on the const parameter `Q`
+   |                                           |
+   |                                           the const parameter `Q` is defined here
    |
    = note: `K` has type `&'r [A; Q]`
 
 error: the type of the associated constant `SELF` must not depend on `impl Trait`
-  --> $DIR/assoc-const-eq-param-in-ty.rs:30:26
+  --> $DIR/assoc-const-eq-param-in-ty.rs:37:26
    |
 LL | fn take1(_: impl Project<SELF = {}>) {}
    |             -------------^^^^------
@@ -34,7 +34,7 @@ LL | fn take1(_: impl Project<SELF = {}>) {}
    |             the `impl Trait` is specified here
 
 error: the type of the associated constant `SELF` must not depend on generic parameters
-  --> $DIR/assoc-const-eq-param-in-ty.rs:35:21
+  --> $DIR/assoc-const-eq-param-in-ty.rs:42:21
    |
 LL | fn take2<P: Project<SELF = {}>>(_: P) {}
    |          -          ^^^^ its type must not depend on the type parameter `P`
@@ -44,9 +44,9 @@ LL | fn take2<P: Project<SELF = {}>>(_: P) {}
    = note: `SELF` has type `P`
 
 error: the type of the associated constant `K` must not depend on generic parameters
-  --> $DIR/assoc-const-eq-param-in-ty.rs:44:52
+  --> $DIR/assoc-const-eq-param-in-ty.rs:51:52
    |
-LL | trait Iface<'r> {
+LL | trait Iface<'r>: ConstParamTy_ {
    |             -- the lifetime parameter `'r` is defined here
 ...
 LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
@@ -55,7 +55,7 @@ LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
    = note: `K` has type `&'r [Self; Q]`
 
 error: the type of the associated constant `K` must not depend on `Self`
-  --> $DIR/assoc-const-eq-param-in-ty.rs:44:52
+  --> $DIR/assoc-const-eq-param-in-ty.rs:51:52
    |
 LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
    |                                                    ^ its type must not depend on `Self`
@@ -63,7 +63,7 @@ LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
    = note: `K` has type `&'r [Self; Q]`
 
 error: the type of the associated constant `K` must not depend on generic parameters
-  --> $DIR/assoc-const-eq-param-in-ty.rs:44:52
+  --> $DIR/assoc-const-eq-param-in-ty.rs:51:52
    |
 LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
    |                      -                             ^ its type must not depend on the const parameter `Q`
@@ -73,9 +73,9 @@ LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
    = note: `K` has type `&'r [Self; Q]`
 
 error: the type of the associated constant `K` must not depend on generic parameters
-  --> $DIR/assoc-const-eq-param-in-ty.rs:44:52
+  --> $DIR/assoc-const-eq-param-in-ty.rs:51:52
    |
-LL | trait Iface<'r> {
+LL | trait Iface<'r>: ConstParamTy_ {
    |             -- the lifetime parameter `'r` is defined here
 ...
 LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
@@ -85,7 +85,7 @@ LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error: the type of the associated constant `K` must not depend on `Self`
-  --> $DIR/assoc-const-eq-param-in-ty.rs:44:52
+  --> $DIR/assoc-const-eq-param-in-ty.rs:51:52
    |
 LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
    |                                                    ^ its type must not depend on `Self`
@@ -94,7 +94,7 @@ LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error: the type of the associated constant `K` must not depend on generic parameters
-  --> $DIR/assoc-const-eq-param-in-ty.rs:44:52
+  --> $DIR/assoc-const-eq-param-in-ty.rs:51:52
    |
 LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
    |                      -                             ^ its type must not depend on the const parameter `Q`
diff --git a/tests/ui/associated-consts/assoc-const-eq-supertraits.rs b/tests/ui/associated-consts/assoc-const-eq-supertraits.rs
index 301ddf2d0104..d9b8a8cd43d7 100644
--- a/tests/ui/associated-consts/assoc-const-eq-supertraits.rs
+++ b/tests/ui/associated-consts/assoc-const-eq-supertraits.rs
@@ -3,12 +3,19 @@
 
 //@ check-pass
 
-#![feature(associated_const_equality, min_generic_const_args)]
+#![feature(
+    associated_const_equality,
+    min_generic_const_args,
+    adt_const_params,
+    unsized_const_params,
+)]
 #![allow(incomplete_features)]
 
+use std::marker::ConstParamTy_;
+
 trait Trait: SuperTrait {}
 trait SuperTrait: SuperSuperTrait<i32> {}
-trait SuperSuperTrait<T> {
+trait SuperSuperTrait<T: ConstParamTy_> {
     #[type_const]
     const K: T;
 }
diff --git a/tests/ui/associated-consts/assoc-const-eq-ty-alias-noninteracting.rs b/tests/ui/associated-consts/assoc-const-eq-ty-alias-noninteracting.rs
index febd838e2c2e..41857eca87de 100644
--- a/tests/ui/associated-consts/assoc-const-eq-ty-alias-noninteracting.rs
+++ b/tests/ui/associated-consts/assoc-const-eq-ty-alias-noninteracting.rs
@@ -5,7 +5,7 @@
 
 //@ check-pass
 
-#![feature(associated_const_equality, min_generic_const_args)]
+#![feature(associated_const_equality, min_generic_const_args, unsized_const_params)]
 #![allow(incomplete_features)]
 
 trait Trait: SuperTrait {
diff --git a/tests/ui/const-generics/mgca/type_const-mismatched-types.rs b/tests/ui/const-generics/mgca/type_const-mismatched-types.rs
new file mode 100644
index 000000000000..8d2eae71d330
--- /dev/null
+++ b/tests/ui/const-generics/mgca/type_const-mismatched-types.rs
@@ -0,0 +1,23 @@
+#![expect(incomplete_features)]
+#![feature(min_generic_const_args)]
+
+#[type_const]
+const FREE: u32 = 5_usize;
+//~^ ERROR mismatched types
+
+#[type_const]
+const FREE2: isize = FREE;
+//~^ ERROR the constant `5` is not of type `isize`
+
+trait Tr {
+    #[type_const]
+    const N: usize;
+}
+
+impl Tr for () {
+    #[type_const]
+    const N: usize = false;
+    //~^ ERROR mismatched types
+}
+
+fn main() {}
diff --git a/tests/ui/const-generics/mgca/type_const-mismatched-types.stderr b/tests/ui/const-generics/mgca/type_const-mismatched-types.stderr
new file mode 100644
index 000000000000..4029bb7b6bff
--- /dev/null
+++ b/tests/ui/const-generics/mgca/type_const-mismatched-types.stderr
@@ -0,0 +1,27 @@
+error: the constant `5` is not of type `isize`
+  --> $DIR/type_const-mismatched-types.rs:9:1
+   |
+LL | const FREE2: isize = FREE;
+   | ^^^^^^^^^^^^^^^^^^ expected `isize`, found `u32`
+
+error[E0308]: mismatched types
+  --> $DIR/type_const-mismatched-types.rs:5:19
+   |
+LL | const FREE: u32 = 5_usize;
+   |                   ^^^^^^^ expected `u32`, found `usize`
+   |
+help: change the type of the numeric literal from `usize` to `u32`
+   |
+LL - const FREE: u32 = 5_usize;
+LL + const FREE: u32 = 5_u32;
+   |
+
+error[E0308]: mismatched types
+  --> $DIR/type_const-mismatched-types.rs:19:22
+   |
+LL |     const N: usize = false;
+   |                      ^^^^^ expected `usize`, found `bool`
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/tests/ui/const-generics/mgca/type_const-not-constparamty.rs b/tests/ui/const-generics/mgca/type_const-not-constparamty.rs
new file mode 100644
index 000000000000..27b446e6a40d
--- /dev/null
+++ b/tests/ui/const-generics/mgca/type_const-not-constparamty.rs
@@ -0,0 +1,26 @@
+#![expect(incomplete_features)]
+#![feature(min_generic_const_args)]
+
+struct S;
+
+// FIXME(mgca): need support for ctors without anon const
+// (we use double-braces to trigger an anon const here)
+#[type_const]
+const FREE: S = { { S } };
+//~^ ERROR `S` must implement `ConstParamTy` to be used as the type of a const generic parameter
+
+trait Tr {
+    #[type_const]
+    const N: S;
+    //~^ ERROR `S` must implement `ConstParamTy` to be used as the type of a const generic parameter
+}
+
+impl Tr for S {
+    // FIXME(mgca): need support for ctors without anon const
+    // (we use double-braces to trigger an anon const here)
+    #[type_const]
+    const N: S = { { S } };
+    //~^ ERROR `S` must implement `ConstParamTy` to be used as the type of a const generic parameter
+}
+
+fn main() {}
diff --git a/tests/ui/const-generics/mgca/type_const-not-constparamty.stderr b/tests/ui/const-generics/mgca/type_const-not-constparamty.stderr
new file mode 100644
index 000000000000..6b13917a95cd
--- /dev/null
+++ b/tests/ui/const-generics/mgca/type_const-not-constparamty.stderr
@@ -0,0 +1,39 @@
+error[E0741]: `S` must implement `ConstParamTy` to be used as the type of a const generic parameter
+  --> $DIR/type_const-not-constparamty.rs:9:13
+   |
+LL | const FREE: S = { { S } };
+   |             ^
+   |
+help: add `#[derive(ConstParamTy, PartialEq, Eq)]` to the struct
+   |
+LL + #[derive(ConstParamTy, PartialEq, Eq)]
+LL | struct S;
+   |
+
+error[E0741]: `S` must implement `ConstParamTy` to be used as the type of a const generic parameter
+  --> $DIR/type_const-not-constparamty.rs:22:14
+   |
+LL |     const N: S = { { S } };
+   |              ^
+   |
+help: add `#[derive(ConstParamTy, PartialEq, Eq)]` to the struct
+   |
+LL + #[derive(ConstParamTy, PartialEq, Eq)]
+LL | struct S;
+   |
+
+error[E0741]: `S` must implement `ConstParamTy` to be used as the type of a const generic parameter
+  --> $DIR/type_const-not-constparamty.rs:14:14
+   |
+LL |     const N: S;
+   |              ^
+   |
+help: add `#[derive(ConstParamTy, PartialEq, Eq)]` to the struct
+   |
+LL + #[derive(ConstParamTy, PartialEq, Eq)]
+LL | struct S;
+   |
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0741`.
diff --git a/tests/crashes/119783.rs b/tests/ui/const-generics/mgca/using-fnptr-as-type_const.rs
similarity index 54%
rename from tests/crashes/119783.rs
rename to tests/ui/const-generics/mgca/using-fnptr-as-type_const.rs
index efde7f89ade2..554e078ccd49 100644
--- a/tests/crashes/119783.rs
+++ b/tests/ui/const-generics/mgca/using-fnptr-as-type_const.rs
@@ -1,9 +1,12 @@
-//@ known-bug: #119783
+// Regression test for #119783
+
+#![expect(incomplete_features)]
 #![feature(associated_const_equality, min_generic_const_args)]
 
 trait Trait {
     #[type_const]
     const F: fn();
+    //~^ ERROR using function pointers as const generic parameters is forbidden
 }
 
 fn take(_: impl Trait<F = { || {} }>) {}
diff --git a/tests/ui/const-generics/mgca/using-fnptr-as-type_const.stderr b/tests/ui/const-generics/mgca/using-fnptr-as-type_const.stderr
new file mode 100644
index 000000000000..09d1063081fe
--- /dev/null
+++ b/tests/ui/const-generics/mgca/using-fnptr-as-type_const.stderr
@@ -0,0 +1,9 @@
+error[E0741]: using function pointers as const generic parameters is forbidden
+  --> $DIR/using-fnptr-as-type_const.rs:8:14
+   |
+LL |     const F: fn();
+   |              ^^^^
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0741`.
diff --git a/tests/ui/generic-const-items/assoc-const-no-infer-ice-115806.rs b/tests/ui/generic-const-items/assoc-const-no-infer-ice-115806.rs
index 57b748a6b475..7f4926fa2b71 100644
--- a/tests/ui/generic-const-items/assoc-const-no-infer-ice-115806.rs
+++ b/tests/ui/generic-const-items/assoc-const-no-infer-ice-115806.rs
@@ -1,6 +1,6 @@
 // ICE: assertion failed: !value.has_infer()
 // issue: rust-lang/rust#115806
-#![feature(associated_const_equality, min_generic_const_args)]
+#![feature(associated_const_equality, min_generic_const_args, unsized_const_params)]
 #![allow(incomplete_features)]
 
 pub struct NoPin;