Rollup merge of rust-lang#121109 - nnethercote:TyKind-Err-guar-2, r=oli-obk

Add an ErrorGuaranteed to ast::TyKind::Err (attempt 2)

This makes it more like `hir::TyKind::Err`, and avoids a `has_errors` assertion in `LoweringContext::lower_ty_direct`.

r? ```@oli-obk```

Author: GuillaumeGomez

clippy_utils/src/ast_utils.rs

@@ -690,7 +690,7 @@ pub fn eq_ty(l: &Ty, r: &Ty) -> bool {
     match (&l.kind, &r.kind) {
         (Paren(l), _) => eq_ty(l, r),
         (_, Paren(r)) => eq_ty(l, r),
-        (Never, Never) | (Infer, Infer) | (ImplicitSelf, ImplicitSelf) | (Err, Err) | (CVarArgs, CVarArgs) => true,
+        (Never, Never) | (Infer, Infer) | (ImplicitSelf, ImplicitSelf) | (Err(_), Err(_)) | (CVarArgs, CVarArgs) => true,
         (Slice(l), Slice(r)) => eq_ty(l, r),
         (Array(le, ls), Array(re, rs)) => eq_ty(le, re) && eq_expr(&ls.value, &rs.value),
         (Ptr(l), Ptr(r)) => l.mutbl == r.mutbl && eq_ty(&l.ty, &r.ty),