Erase lifetimes in SROA.

Author: cjgillot

compiler/rustc_mir_dataflow/src/value_analysis.rs

@@ -690,7 +690,7 @@ impl Map {
         }
 
         // Recurse with all fields of this place.
-        iter_fields(ty, tcx, |variant, field, ty| {
+        iter_fields(ty, tcx, ty::ParamEnv::reveal_all(), |variant, field, ty| {
             if let Some(variant) = variant {
                 projection.push(PlaceElem::Downcast(None, variant));
                 let _ = self.make_place(local, projection);
@@ -939,6 +939,7 @@ impl<V, T> TryFrom<ProjectionElem<V, T>> for TrackElem {
 pub fn iter_fields<'tcx>(
     ty: Ty<'tcx>,
     tcx: TyCtxt<'tcx>,
+    param_env: ty::ParamEnv<'tcx>,
     mut f: impl FnMut(Option<VariantIdx>, Field, Ty<'tcx>),
 ) {
     match ty.kind() {
@@ -956,14 +957,14 @@ pub fn iter_fields<'tcx>(
                 for (f_index, f_def) in v_def.fields.iter().enumerate() {
                     let field_ty = f_def.ty(tcx, substs);
                     let field_ty = tcx
-                        .try_normalize_erasing_regions(ty::ParamEnv::reveal_all(), field_ty)
-                        .unwrap_or(field_ty);
+                        .try_normalize_erasing_regions(param_env, field_ty)
+                        .unwrap_or_else(|_| tcx.erase_regions(field_ty));
                     f(variant, f_index.into(), field_ty);
                 }
             }
         }
         ty::Closure(_, substs) => {
-            iter_fields(substs.as_closure().tupled_upvars_ty(), tcx, f);
+            iter_fields(substs.as_closure().tupled_upvars_ty(), tcx, param_env, f);
         }
         _ => (),
     }

compiler/rustc_mir_transform/src/sroa.rs

@@ -4,7 +4,7 @@ use rustc_index::vec::IndexVec;
 use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::visit::*;
 use rustc_middle::mir::*;
-use rustc_middle::ty::{Ty, TyCtxt};
+use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_mir_dataflow::value_analysis::{excluded_locals, iter_fields};
 
 pub struct ScalarReplacementOfAggregates;
@@ -18,11 +18,12 @@ impl<'tcx> MirPass<'tcx> for ScalarReplacementOfAggregates {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         debug!(def_id = ?body.source.def_id());
         let mut excluded = excluded_locals(body);
+        let param_env = tcx.param_env_reveal_all_normalized(body.source.def_id());
         loop {
             debug!(?excluded);
             let escaping = escaping_locals(&excluded, body);
             debug!(?escaping);
-            let replacements = compute_flattening(tcx, body, escaping);
+            let replacements = compute_flattening(tcx, param_env, body, escaping);
             debug!(?replacements);
             let all_dead_locals = replace_flattened_locals(tcx, body, replacements);
             if !all_dead_locals.is_empty() {
@@ -144,6 +145,7 @@ impl<'tcx> ReplacementMap<'tcx> {
 /// The replacement will be done later in `ReplacementVisitor`.
 fn compute_flattening<'tcx>(
     tcx: TyCtxt<'tcx>,
+    param_env: ty::ParamEnv<'tcx>,
     body: &mut Body<'tcx>,
     escaping: BitSet<Local>,
 ) -> ReplacementMap<'tcx> {
@@ -155,7 +157,7 @@ fn compute_flattening<'tcx>(
         }
         let decl = body.local_decls[local].clone();
         let ty = decl.ty;
-        iter_fields(ty, tcx, |variant, field, field_ty| {
+        iter_fields(ty, tcx, param_env, |variant, field, field_ty| {
             if variant.is_some() {
                 // Downcasts are currently not supported.
                 return;