Rollup merge of #116415 - ouz-a:move_subtyper, r=oli-obk

Move subtyper below reveal_all and change reveal_all

In previous attempt https://github.com/rust-lang/rust/pull/116378 we tried to handle `Opaque` in few different places, but this isn't necessary, after moving subtyper below reveal_all and calling `super_place` on reveal_all, issues cease to exist.

r? ``@oli-obk``

Fixes https://github.com/rust-lang/rust/issues/116332
Fixes https://github.com/rust-lang/rust/issues/116265
Fixes https://github.com/rust-lang/rust/issues/116383
Fixes https://github.com/rust-lang/rust/issues/116333

3 files changed, 9 insertions, 3 deletions

diff --git a/compiler/rustc_mir_transform/src/add_subtyping_projections.rs b/compiler/rustc_mir_transform/src/add_subtyping_projections.rs
index 1cc049d5a22..e5be7c0ca76 100644
--- a/compiler/rustc_mir_transform/src/add_subtyping_projections.rs
+++ b/compiler/rustc_mir_transform/src/add_subtyping_projections.rs
@@ -24,6 +24,11 @@ impl<'a, 'tcx> MutVisitor<'tcx> for SubTypeChecker<'a, 'tcx> {
         rvalue: &mut Rvalue<'tcx>,
         location: Location,
     ) {
+        // We don't need to do anything for deref temps as they are
+        // not part of the source code, but used for desugaring purposes.
+        if self.local_decls[place.local].is_deref_temp() {
+            return;
+        }
         let mut place_ty = place.ty(self.local_decls, self.tcx).ty;
         let mut rval_ty = rvalue.ty(self.local_decls, self.tcx);
         // Not erasing this causes `Free Regions` errors in validator,
@@ -48,7 +53,6 @@ impl<'a, 'tcx> MutVisitor<'tcx> for SubTypeChecker<'a, 'tcx> {
 // // gets transformed to
 // let temp: rval_ty = rval;
 // let place: place_ty = temp as place_ty;
-//
 pub fn subtype_finder<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
     let patch = MirPatch::new(body);
     let mut checker = SubTypeChecker { tcx, patcher: patch, local_decls: &body.local_decls };
diff --git a/compiler/rustc_mir_transform/src/lib.rs b/compiler/rustc_mir_transform/src/lib.rs
index 22381844d6d..c0a09b7a761 100644
--- a/compiler/rustc_mir_transform/src/lib.rs
+++ b/compiler/rustc_mir_transform/src/lib.rs
@@ -467,7 +467,6 @@ pub fn run_analysis_to_runtime_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'
 /// After this series of passes, no lifetime analysis based on borrowing can be done.
 fn run_analysis_cleanup_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
     let passes: &[&dyn MirPass<'tcx>] = &[
-        &add_subtyping_projections::Subtyper,
         &cleanup_post_borrowck::CleanupPostBorrowck,
         &remove_noop_landing_pads::RemoveNoopLandingPads,
         &simplify::SimplifyCfg::EarlyOpt,
@@ -483,6 +482,7 @@ fn run_runtime_lowering_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         // These next passes must be executed together
         &add_call_guards::CriticalCallEdges,
         &reveal_all::RevealAll, // has to be done before drop elaboration, since we need to drop opaque types, too.
+        &add_subtyping_projections::Subtyper, // calling this after reveal_all ensures that we don't deal with opaque types
         &elaborate_drops::ElaborateDrops,
         // This will remove extraneous landing pads which are no longer
         // necessary as well as well as forcing any call in a non-unwinding
diff --git a/compiler/rustc_mir_transform/src/reveal_all.rs b/compiler/rustc_mir_transform/src/reveal_all.rs
index 55f1eac6f84..1626cf3c035 100644
--- a/compiler/rustc_mir_transform/src/reveal_all.rs
+++ b/compiler/rustc_mir_transform/src/reveal_all.rs
@@ -46,16 +46,18 @@ impl<'tcx> MutVisitor<'tcx> for RevealAllVisitor<'tcx> {
                 .filter(|elem| !matches!(elem, ProjectionElem::OpaqueCast(_)))
                 .collect::<Vec<_>>(),
         );
+        self.super_place(place, _context, _location);
     }
 
     #[inline]
-    fn visit_constant(&mut self, constant: &mut ConstOperand<'tcx>, _: Location) {
+    fn visit_constant(&mut self, constant: &mut ConstOperand<'tcx>, location: Location) {
         // We have to use `try_normalize_erasing_regions` here, since it's
         // possible that we visit impossible-to-satisfy where clauses here,
         // see #91745
         if let Ok(c) = self.tcx.try_normalize_erasing_regions(self.param_env, constant.const_) {
             constant.const_ = c;
         }
+        self.super_constant(constant, location);
     }
 
     #[inline]