Don't register predicates for RPITIT items in built-in trait object impl confirmation

Author: compiler-errors

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

@@ -629,8 +629,18 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
             // When `async_fn_in_dyn_trait` is enabled, we don't need to check the
             // RPITIT for compatibility, since it's not provided by the user.
-            if tcx.features().async_fn_in_dyn_trait() && tcx.is_impl_trait_in_trait(assoc_type) {
-                continue;
+            if tcx.is_impl_trait_in_trait(assoc_type) {
+                if tcx.features().async_fn_in_dyn_trait() {
+                    continue;
+                } else {
+                    tcx.dcx().span_delayed_bug(
+                        obligation.cause.span,
+                        "RPITIT in trait object shouldn't have been considered",
+                    );
+                    return Err(SelectionError::TraitDynIncompatible(
+                        trait_predicate.trait_ref.def_id,
+                    ));
+                }
             }
 
             if !defs.own_params.is_empty() && !tcx.features().generic_associated_types_extended() {

tests/crashes/131538.rs

@@ -0,0 +1,30 @@
+warning: the feature `generic_associated_types_extended` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/gat-extended-bad-afit.rs:9:12
+   |
+LL | #![feature(generic_associated_types_extended)]
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #95451 <https://github.com/rust-lang/rust/issues/95451> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+error[E0038]: the trait `HealthCheck` cannot be made into an object
+  --> $DIR/gat-extended-bad-afit.rs:19:22
+   |
+LL |     dyn HealthCheck: HealthCheck,
+   |                      ^^^^^^^^^^^ `HealthCheck` cannot be made into an object
+   |
+note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
+  --> $DIR/gat-extended-bad-afit.rs:14:14
+   |
+LL | trait HealthCheck {
+   |       ----------- this trait cannot be made into an object...
+LL |     async fn check<const N: usize>(&self);
+   |              ^^^^^
+   |              |
+   |              ...because method `check` is `async`
+   |              ...because method `check` has generic type parameters
+   = help: consider moving `check` to another trait
+
+error: aborting due to 1 previous error; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0038`.

tests/ui/async-await/dyn/gat-extended-bad-afit.no.stderr

@@ -0,0 +1,24 @@
+//@ edition: 2021
+//@ revisions: yes no
+
+// Ice regression test for #131538
+// Make sure that we don't crash when the GATE feature gate is enabled.
+
+#![cfg_attr(yes, feature(async_fn_in_dyn_trait))]
+//[yes]~^ WARN the feature `async_fn_in_dyn_trait` is incomplete
+#![feature(generic_associated_types_extended)]
+//~^ WARN the feature `generic_associated_types_extended` is incomplete
+#![feature(trivial_bounds)]
+
+trait HealthCheck {
+    async fn check<const N: usize>(&self);
+}
+
+fn do_health_check_par()
+where
+    dyn HealthCheck: HealthCheck,
+    //~^ ERROR the trait `HealthCheck` cannot be made into an object
+{
+}
+
+fn main() {}

tests/ui/async-await/dyn/gat-extended-bad-afit.rs

@@ -0,0 +1,35 @@
+warning: the feature `async_fn_in_dyn_trait` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/gat-extended-bad-afit.rs:7:26
+   |
+LL | #![cfg_attr(yes, feature(async_fn_in_dyn_trait))]
+   |                          ^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #133119 <https://github.com/rust-lang/rust/issues/133119> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+warning: the feature `generic_associated_types_extended` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/gat-extended-bad-afit.rs:9:12
+   |
+LL | #![feature(generic_associated_types_extended)]
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #95451 <https://github.com/rust-lang/rust/issues/95451> for more information
+
+error[E0038]: the trait `HealthCheck` cannot be made into an object
+  --> $DIR/gat-extended-bad-afit.rs:19:22
+   |
+LL |     dyn HealthCheck: HealthCheck,
+   |                      ^^^^^^^^^^^ `HealthCheck` cannot be made into an object
+   |
+note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
+  --> $DIR/gat-extended-bad-afit.rs:14:14
+   |
+LL | trait HealthCheck {
+   |       ----------- this trait cannot be made into an object...
+LL |     async fn check<const N: usize>(&self);
+   |              ^^^^^ ...because method `check` has generic type parameters
+   = help: consider moving `check` to another trait
+
+error: aborting due to 1 previous error; 2 warnings emitted
+
+For more information about this error, try `rustc --explain E0038`.