Fix AST lowering for const args

Author: camelid

compiler/rustc_ast_lowering/src/lib.rs

@@ -1181,11 +1181,12 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         self.arena.alloc(self.lower_anon_const_as_const_arg_direct(anon))
     }
 
+    #[instrument(level = "debug", skip(self))]
     fn lower_anon_const_as_const_arg_direct(&mut self, anon: &AnonConst) -> hir::ConstArg<'hir> {
         if let ExprKind::Path(qself, path) = &anon.value.kind
             && let Some(res) = self
                 .resolver
-                .get_partial_res(anon.id)
+                .get_partial_res(anon.value.id)
                 .and_then(|partial_res| partial_res.full_res())
             // FIXME(min_generic_const_exprs): for now we only lower params to ConstArgKind::Path
             && let Res::Def(DefKind::ConstParam, _) = res

compiler/rustc_middle/src/ty/consts.rs

@@ -293,7 +293,7 @@ impl<'tcx> Const<'tcx> {
         let hir::QPath::Resolved(_, &hir::Path { res: Res::Def(DefKind::ConstParam, def_id), .. }) =
             qpath
         else {
-            bug!("non-param passed to Const::from_param")
+            span_bug!(qpath.span(), "non-param {qpath:?} passed to Const::from_param")
         };
 
         // Use the type from the param's definition, since we can resolve it,