Use super_fold in RegionsToStatic visitor

Author: compiler-errors

compiler/rustc_next_trait_solver/src/canonicalizer.rs

@@ -455,7 +455,7 @@ impl<I: Interner> TypeFolder<I> for RegionsToStatic<I> {
         I::Binder<T>: TypeSuperFoldable<I>,
     {
         self.binder.shift_in(1);
-        let t = t.fold_with(self);
+        let t = t.super_fold_with(self);
         self.binder.shift_out(1);
         t
     }

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -2583,7 +2583,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
                         self.infcx
                             .at(&obligation.cause, obligation.param_env)
                             .eq(
-                                DefineOpaqueTypes::No,
+                                DefineOpaqueTypes::Yes,
                                 upcast_principal.map_bound(|trait_ref| {
                                     ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref)
                                 }),
@@ -2620,7 +2620,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
                     nested.extend(
                         self.infcx
                             .at(&obligation.cause, obligation.param_env)
-                            .eq(DefineOpaqueTypes::No, source_projection, target_projection)
+                            .eq(DefineOpaqueTypes::Yes, source_projection, target_projection)
                             .map_err(|_| SelectionError::Unimplemented)?
                             .into_obligations(),
                     );

tests/ui/traits/next-solver/canonical/const-region-infer-to-static-in-binder.rs

@@ -0,0 +1,8 @@
+//@ compile-flags: -Znext-solver=coherence
+
+#[derive(Debug)]
+struct X<const FN: fn() = { || {} }>;
+//~^ ERROR using function pointers as const generic parameters is forbidden
+//~| ERROR using function pointers as const generic parameters is forbidden
+
+fn main() {}

tests/ui/traits/next-solver/canonical/const-region-infer-to-static-in-binder.stderr

@@ -0,0 +1,19 @@
+error: using function pointers as const generic parameters is forbidden
+  --> $DIR/const-region-infer-to-static-in-binder.rs:4:20
+   |
+LL | struct X<const FN: fn() = { || {} }>;
+   |                    ^^^^
+   |
+   = note: the only supported types are integers, `bool` and `char`
+
+error: using function pointers as const generic parameters is forbidden
+  --> $DIR/const-region-infer-to-static-in-binder.rs:4:20
+   |
+LL | struct X<const FN: fn() = { || {} }>;
+   |                    ^^^^
+   |
+   = note: the only supported types are integers, `bool` and `char`
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 2 previous errors
+