Use ConstCx in more places

Author: oli-obk

src/librustc_mir/borrow_check/type_check/mod.rs

@@ -42,7 +42,10 @@ use rustc_trait_selection::traits::{self, ObligationCause, PredicateObligations}
 use crate::dataflow::move_paths::MoveData;
 use crate::dataflow::MaybeInitializedPlaces;
 use crate::dataflow::ResultsCursor;
-use crate::transform::promote_consts::should_suggest_const_in_array_repeat_expressions_attribute;
+use crate::transform::{
+    check_consts::ConstCx,
+    promote_consts::should_suggest_const_in_array_repeat_expressions_attribute,
+};
 
 use crate::borrow_check::{
     borrow_set::BorrowSet,
@@ -1997,14 +2000,17 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                         let span = body.source_info(location).span;
                         let ty = operand.ty(*body, tcx);
                         if !self.infcx.type_is_copy_modulo_regions(self.param_env, ty, span) {
+                            let ccx = ConstCx::new_with_param_env(
+                                tcx,
+                                self.mir_def_id,
+                                body,
+                                self.param_env,
+                            );
                             // To determine if `const_in_array_repeat_expressions` feature gate should
                             // be mentioned, need to check if the rvalue is promotable.
                             let should_suggest =
                                 should_suggest_const_in_array_repeat_expressions_attribute(
-                                    tcx,
-                                    self.mir_def_id,
-                                    body,
-                                    operand,
+                                    ccx, operand,
                                 );
                             debug!("check_rvalue: should_suggest={:?}", should_suggest);
 

src/librustc_mir/transform/check_consts/mod.rs

@@ -35,6 +35,15 @@ impl ConstCx<'mir, 'tcx> {
         body: mir::ReadOnlyBodyAndCache<'mir, 'tcx>,
     ) -> Self {
         let param_env = tcx.param_env(def_id);
+        Self::new_with_param_env(tcx, def_id, body, param_env)
+    }
+
+    pub fn new_with_param_env(
+        tcx: TyCtxt<'tcx>,
+        def_id: DefId,
+        body: mir::ReadOnlyBodyAndCache<'mir, 'tcx>,
+        param_env: ty::ParamEnv<'tcx>,
+    ) -> Self {
         let const_kind = ConstKind::for_item(tcx, def_id);
 
         ConstCx { body, tcx, def_id, param_env, const_kind }

src/librustc_mir/transform/promote_consts.rs

@@ -1153,22 +1153,19 @@ pub fn promote_candidates<'tcx>(
 /// Feature attribute should be suggested if `operand` can be promoted and the feature is not
 /// enabled.
 crate fn should_suggest_const_in_array_repeat_expressions_attribute<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    mir_def_id: DefId,
-    body: ReadOnlyBodyAndCache<'_, 'tcx>,
+    ccx: ConstCx<'_, 'tcx>,
     operand: &Operand<'tcx>,
 ) -> bool {
-    let mut rpo = traversal::reverse_postorder(&body);
-    let (temps, _) = collect_temps_and_candidates(tcx, &body, &mut rpo);
-    let validator =
-        Validator { ccx: ConstCx::new(tcx, mir_def_id, body), temps: &temps, explicit: false };
+    let mut rpo = traversal::reverse_postorder(&ccx.body);
+    let (temps, _) = collect_temps_and_candidates(ccx.tcx, &ccx.body, &mut rpo);
+    let validator = Validator { ccx, temps: &temps, explicit: false };
 
     let should_promote = validator.validate_operand(operand).is_ok();
-    let feature_flag = tcx.features().const_in_array_repeat_expressions;
+    let feature_flag = validator.ccx.tcx.features().const_in_array_repeat_expressions;
     debug!(
-        "should_suggest_const_in_array_repeat_expressions_flag: mir_def_id={:?} \
+        "should_suggest_const_in_array_repeat_expressions_flag: def_id={:?} \
             should_promote={:?} feature_flag={:?}",
-        mir_def_id, should_promote, feature_flag
+        validator.ccx.def_id, should_promote, feature_flag
     );
     should_promote && !feature_flag
 }