Merge pull request #20321 from rust-lang/rustc-pull

Rustc pull update

6 files changed, 23 insertions, 16 deletions

diff --git a/compiler/rustc_mir_transform/src/add_retag.rs b/compiler/rustc_mir_transform/src/add_retag.rs
index 3c29d4624b7..fc08c1df870 100644
--- a/compiler/rustc_mir_transform/src/add_retag.rs
+++ b/compiler/rustc_mir_transform/src/add_retag.rs
@@ -4,7 +4,6 @@
 //! of MIR building, and only after this pass we think of the program has having the
 //! normal MIR semantics.
 
-use rustc_hir::LangItem;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 
@@ -28,7 +27,6 @@ fn may_contain_reference<'tcx>(ty: Ty<'tcx>, depth: u32, tcx: TyCtxt<'tcx>) -> b
         // References and Boxes (`noalias` sources)
         ty::Ref(..) => true,
         ty::Adt(..) if ty.is_box() => true,
-        ty::Adt(adt, _) if tcx.is_lang_item(adt.did(), LangItem::PtrUnique) => true,
         // Compound types: recurse
         ty::Array(ty, _) | ty::Slice(ty) => {
             // This does not branch so we keep the depth the same.
diff --git a/compiler/rustc_mir_transform/src/elaborate_drops.rs b/compiler/rustc_mir_transform/src/elaborate_drops.rs
index b4fa2be1d00..58dff4514a0 100644
--- a/compiler/rustc_mir_transform/src/elaborate_drops.rs
+++ b/compiler/rustc_mir_transform/src/elaborate_drops.rs
@@ -253,8 +253,8 @@ struct ElaborateDropsCtxt<'a, 'tcx> {
 }
 
 impl fmt::Debug for ElaborateDropsCtxt<'_, '_> {
-    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        Ok(())
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("ElaborateDropsCtxt").finish_non_exhaustive()
     }
 }
 
diff --git a/compiler/rustc_mir_transform/src/gvn.rs b/compiler/rustc_mir_transform/src/gvn.rs
index 6657f89ceb5..dc99b67a1e8 100644
--- a/compiler/rustc_mir_transform/src/gvn.rs
+++ b/compiler/rustc_mir_transform/src/gvn.rs
@@ -1542,7 +1542,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
 fn op_to_prop_const<'tcx>(
     ecx: &mut InterpCx<'tcx, DummyMachine>,
     op: &OpTy<'tcx>,
-) -> Option<ConstValue<'tcx>> {
+) -> Option<ConstValue> {
     // Do not attempt to propagate unsized locals.
     if op.layout.is_unsized() {
         return None;
diff --git a/compiler/rustc_mir_transform/src/impossible_predicates.rs b/compiler/rustc_mir_transform/src/impossible_predicates.rs
index 86e2bf6cb3c..b03518de00a 100644
--- a/compiler/rustc_mir_transform/src/impossible_predicates.rs
+++ b/compiler/rustc_mir_transform/src/impossible_predicates.rs
@@ -27,7 +27,7 @@
 //! it's usually never invoked in this way.
 
 use rustc_middle::mir::{Body, START_BLOCK, TerminatorKind};
-use rustc_middle::ty::{TyCtxt, TypeVisitableExt};
+use rustc_middle::ty::{TyCtxt, TypeFlags, TypeVisitableExt};
 use rustc_trait_selection::traits;
 use tracing::trace;
 
@@ -36,14 +36,23 @@ use crate::pass_manager::MirPass;
 pub(crate) struct ImpossiblePredicates;
 
 impl<'tcx> MirPass<'tcx> for ImpossiblePredicates {
+    #[tracing::instrument(level = "trace", skip(self, tcx, body))]
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        let predicates = tcx
-            .predicates_of(body.source.def_id())
-            .predicates
-            .iter()
-            .filter_map(|(p, _)| if p.is_global() { Some(*p) } else { None });
-        if traits::impossible_predicates(tcx, traits::elaborate(tcx, predicates).collect()) {
-            trace!("found unsatisfiable predicates for {:?}", body.source);
+        tracing::trace!(def_id = ?body.source.def_id());
+        let predicates = tcx.predicates_of(body.source.def_id()).instantiate_identity(tcx);
+        tracing::trace!(?predicates);
+        let predicates = predicates.predicates.into_iter().filter(|p| {
+            !p.has_type_flags(
+                // Only consider global clauses to simplify.
+                TypeFlags::HAS_FREE_LOCAL_NAMES
+                // Clauses that refer to unevaluated constants as they cause cycles.
+                | TypeFlags::HAS_CT_PROJECTION,
+            )
+        });
+        let predicates: Vec<_> = traits::elaborate(tcx, predicates).collect();
+        tracing::trace!(?predicates);
+        if predicates.references_error() || traits::impossible_predicates(tcx, predicates) {
+            trace!("found unsatisfiable predicates");
             // Clear the body to only contain a single `unreachable` statement.
             let bbs = body.basic_blocks.as_mut();
             bbs.raw.truncate(1);
diff --git a/compiler/rustc_mir_transform/src/shim.rs b/compiler/rustc_mir_transform/src/shim.rs
index cdbc74cdfa8..6c65b072bec 100644
--- a/compiler/rustc_mir_transform/src/shim.rs
+++ b/compiler/rustc_mir_transform/src/shim.rs
@@ -434,8 +434,8 @@ pub(super) struct DropShimElaborator<'a, 'tcx> {
 }
 
 impl fmt::Debug for DropShimElaborator<'_, '_> {
-    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
-        Ok(())
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
+        f.debug_struct("DropShimElaborator").finish_non_exhaustive()
     }
 }
 
diff --git a/compiler/rustc_mir_transform/src/unreachable_prop.rs b/compiler/rustc_mir_transform/src/unreachable_prop.rs
index 13fb5b3e56f..c417a9272f2 100644
--- a/compiler/rustc_mir_transform/src/unreachable_prop.rs
+++ b/compiler/rustc_mir_transform/src/unreachable_prop.rs
@@ -75,7 +75,7 @@ fn remove_successors_from_switch<'tcx>(
     let is_unreachable = |bb| unreachable_blocks.contains(&bb);
 
     // If there are multiple targets, we want to keep information about reachability for codegen.
-    // For example (see tests/codegen/match-optimizes-away.rs)
+    // For example (see tests/codegen-llvm/match-optimizes-away.rs)
     //
     // pub enum Two { A, B }
     // pub fn identity(x: Two) -> Two {