only call typeck_tables_of_const_arg for const args

Author: lcnr

src/librustc_middle/query/mod.rs

@@ -579,11 +579,11 @@ rustc_queries! {
             desc { |tcx| "type-checking `{}`", tcx.def_path_str(key.to_def_id()) }
             cache_on_disk_if { true }
         }
-        query typeck_tables_of_const_arg(
+        query _typeck_tables_of_const_arg(
             key: ty::WithOptParam<LocalDefId>
         ) -> &'tcx ty::TypeckTables<'tcx> {
             desc {
-                |tcx| "type-checking the potential const argument `{}`",
+                |tcx| "type-checking the const argument `{}`",
                 tcx.def_path_str(key.did.to_def_id()),
             }
         }

src/librustc_middle/ty/context.rs

@@ -980,6 +980,17 @@ pub struct GlobalCtxt<'tcx> {
 }
 
 impl<'tcx> TyCtxt<'tcx> {
+    pub fn typeck_tables_of_const_arg(
+        self,
+        def: ty::WithOptParam<LocalDefId>,
+    ) -> &'tcx TypeckTables<'tcx> {
+        if def.param_did.is_some() {
+            self._typeck_tables_of_const_arg(def)
+        } else {
+            self.typeck_tables_of(def.did)
+        }
+    }
+
     pub fn alloc_steal_mir(self, mir: Body<'tcx>) -> &'tcx Steal<Body<'tcx>> {
         self.arena.alloc(Steal::new(mir))
     }

src/librustc_typeck/check/mod.rs

@@ -764,7 +764,7 @@ pub fn provide(providers: &mut Providers) {
     method::provide(providers);
     *providers = Providers {
         typeck_item_bodies,
-        typeck_tables_of_const_arg,
+        _typeck_tables_of_const_arg: typeck_tables_of_const_arg,
         typeck_tables_of,
         diagnostic_only_typeck_tables_of,
         has_typeck_tables,
@@ -964,7 +964,7 @@ fn typeck_tables_of_const_arg<'tcx>(
         let fallback = move || tcx.type_of(param_did);
         typeck_tables_of_with_fallback(tcx, def.did, fallback)
     } else {
-        tcx.typeck_tables_of(def.did)
+        bug!("missing param_did")
     }
 }