Rollup merge of #131049 - compiler-errors:more-validation, r=spastorino

Validate args are correct for `UnevaluatedConst`, `ExistentialTraitRef`/`ExistentialProjection`

For the `Existential*` ones, we have to do some adjustment to the args list to deal with the missing `Self` type, so we introduce a `debug_assert_existential_args_compatible` function to the interner as well.

2 files changed, 21 insertions, 0 deletions

diff --git a/compiler/rustc_middle/src/ty/consts.rs b/compiler/rustc_middle/src/ty/consts.rs
index eb715be22b1..5ab85a69ce6 100644
--- a/compiler/rustc_middle/src/ty/consts.rs
+++ b/compiler/rustc_middle/src/ty/consts.rs
@@ -109,6 +109,7 @@ impl<'tcx> Const<'tcx> {
 
     #[inline]
     pub fn new_unevaluated(tcx: TyCtxt<'tcx>, uv: ty::UnevaluatedConst<'tcx>) -> Const<'tcx> {
+        tcx.debug_assert_args_compatible(uv.def, uv.args);
         Const::new(tcx, ty::ConstKind::Unevaluated(uv))
     }
 
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index c2a55060490..135d30f6e96 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -279,6 +279,26 @@ impl<'tcx> Interner for TyCtxt<'tcx> {
         self.debug_assert_args_compatible(def_id, args);
     }
 
+    /// Assert that the args from an `ExistentialTraitRef` or `ExistentialProjection`
+    /// are compatible with the `DefId`. Since we're missing a `Self` type, stick on
+    /// a dummy self type and forward to `debug_assert_args_compatible`.
+    fn debug_assert_existential_args_compatible(
+        self,
+        def_id: Self::DefId,
+        args: Self::GenericArgs,
+    ) {
+        // FIXME: We could perhaps add a `skip: usize` to `debug_assert_args_compatible`
+        // to avoid needing to reintern the set of args...
+        if cfg!(debug_assertions) {
+            self.debug_assert_args_compatible(
+                def_id,
+                self.mk_args_from_iter(
+                    [self.types.trait_object_dummy_self.into()].into_iter().chain(args.iter()),
+                ),
+            );
+        }
+    }
+
     fn mk_type_list_from_iter<I, T>(self, args: I) -> T::Output
     where
         I: Iterator<Item = T>,