reintroduce check RibKind::ConstParamTy did in direct consts

compiler/rustc_hir_analysis/src/check/check.rs

@@ -961,8 +961,7 @@ pub(crate) fn check_item_type(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Result<(),
                     tcx.require_lang_item(LangItem::Sized, ty_span),
                 );
                 check_where_clauses(wfcx, def_id);
-                wfcheck::check_const_item(wfcx, def_id, ty);
-                Ok(())
+                wfcheck::check_const_item(wfcx, def_id, ty)
             }));
 
             // Only `Node::Item` and `Node::ForeignItem` still have HIR based

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -47,8 +47,7 @@ use tracing::{debug, instrument};
 use super::compare_eii::{compare_eii_function_types, compare_eii_statics};
 use crate::autoderef::Autoderef;
 use crate::constrained_generic_params::{Parameter, identify_constrained_generic_params};
-use crate::diagnostics;
-use crate::diagnostics::InvalidReceiverTyHint;
+use crate::diagnostics::{self, InvalidReceiverTyHint, ParamInTyOfConstParam};
 
 pub(super) struct WfCheckingCtxt<'a, 'tcx> {
     pub(super) ocx: ObligationCtxt<'a, 'tcx, FulfillmentError<'tcx>>,
@@ -927,7 +926,6 @@ pub(crate) fn check_associated_item(
                 let ty = tcx.type_of(def_id).instantiate_identity();
                 let ty = wfcx.deeply_normalize(span, Some(WellFormedLoc::Ty(def_id)), ty);
                 wfcx.register_wf_obligation(span, loc, ty.into());
-                check_const_item(wfcx, def_id, ty);
 
                 if item.defaultness(tcx).has_value() {
                     let code = ObligationCauseCode::SizedConstOrStatic;
@@ -939,7 +937,7 @@ pub(crate) fn check_associated_item(
                     );
                 }
 
-                Ok(())
+                check_const_item(wfcx, def_id, ty)
             }
             ty::AssocKind::Fn { .. } => {
                 let sig = tcx.fn_sig(def_id).instantiate_identity().skip_norm_wip();
@@ -1259,22 +1257,33 @@ pub(crate) fn check_static_item<'tcx>(
 }
 
 /// Runs checks common to both free consts and associated consts
-#[instrument(level = "debug", skip(wfcx))]
+#[instrument(level = "debug", skip(wfcx), ret)]
 pub(super) fn check_const_item<'tcx>(
     wfcx: &WfCheckingCtxt<'_, 'tcx>,
     def_id: LocalDefId,
     item_ty: Ty<'tcx>,
-) {
+) -> Result<(), ErrorGuaranteed> {
     let tcx = wfcx.tcx();
     let span = tcx.def_span(def_id);
 
-    if tcx.is_direct_const(def_id.into()) && !tcx.features().const_param_ty_unchecked() {
-        wfcx.register_bound(
-            ObligationCause::new(span, def_id, ObligationCauseCode::ConstParam(item_ty)),
-            wfcx.param_env,
-            item_ty,
-            tcx.require_lang_item(LangItem::ConstParamTy, span),
-        );
+    let mut res = Ok(());
+
+    if tcx.is_direct_const(def_id.into()) {
+        if !tcx.features().const_param_ty_unchecked() {
+            wfcx.register_bound(
+                ObligationCause::new(span, def_id, ObligationCauseCode::ConstParam(item_ty)),
+                wfcx.param_env,
+                item_ty,
+                tcx.require_lang_item(LangItem::ConstParamTy, span),
+            );
+        }
+        // FIXME(min_generic_const_args): We *might* want to move this check to `type_of`, so we can
+        // return `ty::Error` if it references invalid params. However, doing so is hard, because
+        // `type_of` doesn't know if it's a direct const - `const_of_item` determines that, and
+        // `const_of_item` calls `type_of`.
+        if !tcx.features().generic_const_parameter_types() && item_ty.has_param() {
+            res = Err(tcx.dcx().emit_err(ParamInTyOfConstParam { span, ty: item_ty }));
+        }
     }
 
     if let Some(direct_rhs) = tcx.const_of_item(def_id) {
@@ -1289,6 +1298,8 @@ pub(super) fn check_const_item<'tcx>(
             ty::PredicateKind::Clause(ty::ClauseKind::ConstArgHasType(norm_ct, item_ty)),
         ));
     }
+
+    res
 }
 
 #[instrument(level = "debug", skip(tcx, impl_))]

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -2396,16 +2396,11 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             // we have the ability to intermix typeck of anon const const args with the parent
             // bodies typeck.
 
-            // FIXME(min_generic_const_args): This check should be removed for mGCA, it is due to
-            // the lack of ConstParamTy rib-checking in nameres for directly represented const
-            // items.
-
             // We also error if the type contains any regions as effectively any region will wind
             // up as a region variable in mir borrowck. It would also be somewhat concerning if
             // hir typeck was using equality but mir borrowck wound up using subtyping as that could
             // result in a non-infer in hir typeck but a region variable in borrowck.
-            if (tcx.features().generic_const_parameter_types()
-                || tcx.features().min_generic_const_args())
+            if tcx.features().generic_const_parameter_types()
                 && (ty.has_free_regions() || ty.has_erased_regions())
             {
                 let e = self.dcx().span_err(

tests/ui/const-generics/mgca/type_const-generic-param-in-type.nogate.stderr

@@ -1,38 +1,57 @@
-error: anonymous constants referencing generics are not yet supported
-  --> $DIR/type_const-generic-param-in-type.rs:8:77
+error[E0770]: the type of const parameters must not depend on other generic parameters
+  --> $DIR/type_const-generic-param-in-type.rs:12:1
    |
-LL | const FOO<T: core::marker::ConstParamTy_>: [T; 0] = core::direct_const_arg!(const { [] });
-   |                                                                             ^^^^^^^^^^^^
+LL | const FOO<T: core::marker::ConstParamTy_>: [T; 0] = core::direct_const_arg!([]);
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the type `[T; 0]` must not depend on other generic parameter
 
-error: anonymous constants referencing generics are not yet supported
-  --> $DIR/type_const-generic-param-in-type.rs:11:62
+error[E0770]: the type of const parameters must not depend on other generic parameters
+  --> $DIR/type_const-generic-param-in-type.rs:15:1
    |
-LL | const BAR<const N: usize>: [(); N] = core::direct_const_arg!(const { [] });
-   |                                                              ^^^^^^^^^^^^
+LL | const BAR<const N: usize>: StructWithConstParam<N> =
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the type `StructWithConstParam<N>` must not depend on other generic parameter
 
-error: anonymous constants with lifetimes in their type are not yet supported
-  --> $DIR/type_const-generic-param-in-type.rs:14:54
+error[E0770]: the type of const parameters must not depend on other generic parameters
+  --> $DIR/type_const-generic-param-in-type.rs:19:1
    |
-LL | const BAZ<'a>: [&'a (); 0] = core::direct_const_arg!(const { [] });
-   |                                                      ^^^^^^^^^^^^
+LL | const BAZ<'a>: [&'a (); 0] = core::direct_const_arg!([]);
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^ the type `[&'a (); 0]` must not depend on other generic parameter
 
-error: anonymous constants referencing generics are not yet supported
-  --> $DIR/type_const-generic-param-in-type.rs:30:83
+error[E0770]: the type of const parameters must not depend on other generic parameters
+  --> $DIR/type_const-generic-param-in-type.rs:37:5
    |
-LL |     const ASSOC<T: core::marker::ConstParamTy_>: [T; 0] = core::direct_const_arg!(const { [] });
-   |                                                                                   ^^^^^^^^^^^^
+LL |     const ASSOC<T: core::marker::ConstParamTy_>: [T; 0] = core::direct_const_arg!([]);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the type `[T; 0]` must not depend on other generic parameter
 
-error: anonymous constants referencing generics are not yet supported
-  --> $DIR/type_const-generic-param-in-type.rs:33:74
+error[E0770]: the type of const parameters must not depend on other generic parameters
+  --> $DIR/type_const-generic-param-in-type.rs:40:5
    |
-LL |     const ASSOC_CONST<const N: usize>: [(); N] = core::direct_const_arg!(const { [] });
-   |                                                                          ^^^^^^^^^^^^
+LL |     const ASSOC_CONST<const N: usize>: StructWithConstParam<N> =
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the type `StructWithConstParam<N>` must not depend on other generic parameter
 
-error: anonymous constants with lifetimes in their type are not yet supported
-  --> $DIR/type_const-generic-param-in-type.rs:36:63
+error[E0770]: the type of const parameters must not depend on other generic parameters
+  --> $DIR/type_const-generic-param-in-type.rs:44:5
    |
-LL |     const ASSOC_LT<'a>: [&'a (); 0] = core::direct_const_arg!(const { [] });
-   |                                                               ^^^^^^^^^^^^
+LL |     const ASSOC_LT<'a>: [&'a (); 0] = core::direct_const_arg!([]);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the type `[&'a (); 0]` must not depend on other generic parameter
 
-error: aborting due to 6 previous errors
+error[E0770]: the type of const parameters must not depend on other generic parameters
+  --> $DIR/type_const-generic-param-in-type.rs:24:5
+   |
+LL |     const ASSOC<T: core::marker::ConstParamTy_>: [T; 0];
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the type `[T; 0]` must not depend on other generic parameter
+
+error[E0770]: the type of const parameters must not depend on other generic parameters
+  --> $DIR/type_const-generic-param-in-type.rs:28:5
+   |
+LL |     const ASSOC_CONST<const N: usize>: StructWithConstParam<N>;
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the type `StructWithConstParam<N>` must not depend on other generic parameter
+
+error[E0770]: the type of const parameters must not depend on other generic parameters
+  --> $DIR/type_const-generic-param-in-type.rs:32:5
+   |
+LL |     const ASSOC_LT<'a>: [&'a (); 0];
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the type `[&'a (); 0]` must not depend on other generic parameter
+
+error: aborting due to 9 previous errors
 
+For more information about this error, try `rustc --explain E0770`.

tests/ui/const-generics/mgca/type_const-generic-param-in-type.rs

@@ -1,40 +1,48 @@
 //@ revisions: nogate gate
-//@ [gate] check-fail
-// FIXME(generic_const_parameter_types): this should pass
+//@ [gate] check-pass
 #![expect(incomplete_features)]
 #![feature(adt_const_params, unsized_const_params, min_generic_const_args, generic_const_items)]
 #![cfg_attr(gate, feature(generic_const_parameter_types))]
 
-const FOO<T: core::marker::ConstParamTy_>: [T; 0] = core::direct_const_arg!(const { [] });
-//~^ ERROR anonymous constants referencing generics are not yet supported
+use std::marker::ConstParamTy;
 
-const BAR<const N: usize>: [(); N] = core::direct_const_arg!(const { [] });
-//~^ ERROR anonymous constants referencing generics are not yet supported
+#[derive(ConstParamTy, PartialEq, Eq, Debug)]
+struct StructWithConstParam<const N: usize>;
 
-const BAZ<'a>: [&'a (); 0] = core::direct_const_arg!(const { [] });
-//~^ ERROR anonymous constants with lifetimes in their type are not yet supported
+const FOO<T: core::marker::ConstParamTy_>: [T; 0] = core::direct_const_arg!([]);
+//[nogate]~^ ERROR the type of const parameters must not depend on other generic parameters
+
+const BAR<const N: usize>: StructWithConstParam<N> =
+    //[nogate]~^ ERROR the type of const parameters must not depend on other generic parameters
+    core::direct_const_arg!(StructWithConstParam::<N>);
+
+const BAZ<'a>: [&'a (); 0] = core::direct_const_arg!([]);
+//[nogate]~^ ERROR the type of const parameters must not depend on other generic parameters
 
 trait Tr {
-    // FIXME(min_generic_const_args): These should error under [nogate]
     #[rustc_always_gca]
     const ASSOC<T: core::marker::ConstParamTy_>: [T; 0];
+    //[nogate]~^ ERROR the type of const parameters must not depend on other generic parameters
 
     #[rustc_always_gca]
-    const ASSOC_CONST<const N: usize>: [(); N];
+    const ASSOC_CONST<const N: usize>: StructWithConstParam<N>;
+    //[nogate]~^ ERROR the type of const parameters must not depend on other generic parameters
 
     #[rustc_always_gca]
     const ASSOC_LT<'a>: [&'a (); 0];
+    //[nogate]~^ ERROR the type of const parameters must not depend on other generic parameters
 }
 
 impl Tr for () {
-    const ASSOC<T: core::marker::ConstParamTy_>: [T; 0] = core::direct_const_arg!(const { [] });
-    //~^ ERROR anonymous constants referencing generics are not yet supported
+    const ASSOC<T: core::marker::ConstParamTy_>: [T; 0] = core::direct_const_arg!([]);
+    //[nogate]~^ ERROR the type of const parameters must not depend on other generic parameters
 
-    const ASSOC_CONST<const N: usize>: [(); N] = core::direct_const_arg!(const { [] });
-    //~^ ERROR anonymous constants referencing generics are not yet supported
+    const ASSOC_CONST<const N: usize>: StructWithConstParam<N> =
+        //[nogate]~^ ERROR the type of const parameters must not depend on other generic parameters
+        core::direct_const_arg!(StructWithConstParam::<N>);
 
-    const ASSOC_LT<'a>: [&'a (); 0] = core::direct_const_arg!(const { [] });
-    //~^ ERROR anonymous constants with lifetimes in their type are not yet supported
+    const ASSOC_LT<'a>: [&'a (); 0] = core::direct_const_arg!([]);
+    //[nogate]~^ ERROR the type of const parameters must not depend on other generic parameters
 }
 
 fn main() {}

tests/ui/generic-const-items/assoc-const-no-infer-ice-115806.rs

@@ -11,16 +11,14 @@ impl<TA> Pins<TA> for NoPin {}
 pub trait PinA<PER> {
     #[rustc_always_gca]
     const A: &'static () = core::direct_const_arg!(const { &() });
-    //~^ ERROR anonymous constants with lifetimes in their type are not yet supported
 }
 
 pub trait Pins<USART> {}
 
 impl<USART, T> Pins<USART> for T
 //~^ ERROR conflicting implementations of trait `Pins<_>` for type `NoPin`
 where
-    T: PinA<USART, A = { core::direct_const_arg!(const { &() }) }>,
-    //~^ ERROR anonymous constants with lifetimes in their type are not yet supported
+    T: PinA<USART, A = { core::direct_const_arg!(const { &() }) }>
 {
 }
 

tests/ui/generic-const-items/assoc-const-no-infer-ice-115806.stderr

@@ -1,29 +1,17 @@
-error: anonymous constants with lifetimes in their type are not yet supported
-  --> $DIR/assoc-const-no-infer-ice-115806.rs:22:50
-   |
-LL |     T: PinA<USART, A = { core::direct_const_arg!(const { &() }) }>,
-   |                                                  ^^^^^^^^^^^^^
-
 error[E0119]: conflicting implementations of trait `Pins<_>` for type `NoPin`
-  --> $DIR/assoc-const-no-infer-ice-115806.rs:19:1
+  --> $DIR/assoc-const-no-infer-ice-115806.rs:18:1
    |
 LL |   impl<TA> Pins<TA> for NoPin {}
    |   --------------------------- first implementation here
 ...
 LL | / impl<USART, T> Pins<USART> for T
 LL | |
 LL | | where
-LL | |     T: PinA<USART, A = { core::direct_const_arg!(const { &() }) }>,
-   | |___________________________________________________________________^ conflicting implementation for `NoPin`
+LL | |     T: PinA<USART, A = { core::direct_const_arg!(const { &() }) }>
+   | |__________________________________________________________________^ conflicting implementation for `NoPin`
    |
    = note: downstream crates may implement trait `PinA<_>` for type `NoPin`
 
-error: anonymous constants with lifetimes in their type are not yet supported
-  --> $DIR/assoc-const-no-infer-ice-115806.rs:13:52
-   |
-LL |     const A: &'static () = core::direct_const_arg!(const { &() });
-   |                                                    ^^^^^^^^^^^^^
-
-error: aborting due to 3 previous errors
+error: aborting due to 1 previous error
 
 For more information about this error, try `rustc --explain E0119`.